Calculators

Mortgage Overpayment Calculator — See exactly how much interest and time you save by overpaying your mortgage. Instant amortization schedule plus a clear breakdown of the months you save.

Debt Payoff Calculator: Avalanche vs Snowball — Compare the avalanche and snowball debt payoff strategies side by side. See how much interest you save and how many months sooner you'll be debt-free.

Freelance Hourly Rate Calculator — Calculate your freelance hourly rate accounting for taxes, business expenses, and a profit margin. Find out exactly what to charge to hit your income goal.

Compound Interest Calculator — Calculate compound interest with monthly contributions. See your balance grow year by year and discover exactly how much of your final balance is pure interest. Supports Verifiable Calculation Certificates: pass certify=true to also receive a signed, independently veri

Savings Goal Calculator — Calculate the monthly savings you need to reach any goal. Input your target, current balance, annual rate, and years to see your required monthly contribution.

Car Loan Calculator with Sales Tax and Trade-In — Calculate your exact monthly car payment including sales tax and trade-in. View your full amortization schedule, total interest paid, and cost of ownership.

Break-Even Point Calculator — Calculate your break-even point in units and revenue. Enter fixed costs, variable cost per unit, and price to see exactly when your business turns profitable.

Margin and Markup Calculator — Calculate gross profit, margin percentage, and markup percentage instantly. Enter cost and price to see the right number for your business pricing strategy.

Rent vs Buy Calculator — Compare renting vs buying over any timeline. See which builds more wealth, when break-even hits, and how appreciation and rent increases tip the balance.

FIRE Calculator: When Can You Retire Early? — Calculate your FIRE number and years to early retirement. Enter current savings, annual expenses, and expected return rate to reach financial independence.

Take-Home Pay Calculator (US) — Estimate your US take-home pay for 2026. Enter gross salary and filing status to see federal income tax, Social Security, Medicare, and monthly net income.

Student Loan Payoff Calculator — See exactly how many months until you pay off your student loans, how much extra payments save in interest, and whether refinancing makes financial sense.

APY Calculator: APR to APY Conversion — Convert your nominal rate (APR) to APY instantly. See how compounding frequency—daily, monthly, or quarterly—affects your true annual yield and final balance.

ROI Calculator with Annualized Return — Calculate ROI and annualized return on any investment. Add fees and costs to see true net gain and the real annual growth rate behind the headline number.

Loan Amortization Calculator — Get your full loan amortization schedule instantly. See how each payment splits between interest and principal, and how extra payments cut total interest paid.

Paint Calculator: How Much Paint Do I Need? — Calculate exactly how much paint you need for any room. Enter room dimensions, number of coats, doors, windows, and paint coverage to get total liters and cans.

Mortgage Refinance Calculator — Find out if refinancing your mortgage is worth it. Compare monthly payments, see when you break even, and spot if a lower rate actually costs more overall.

TDEE Calculator: Daily Calorie Needs — Calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor formula. Find your daily calorie needs for fat loss, maintenance, or muscle gain.

Macro Calculator: Protein, Carbs and Fat Targets — Calculate your daily protein, carb, and fat targets from your calorie goal. Choose a preset split or customize macros for your fitness or body-composition plan.

Running Pace Calculator with Race Predictions — Calculate your per-km and per-mile running pace from any distance and time. Get predicted finish times for 5K, 10K, half marathon, and marathon, plus splits.

Rent Affordability Calculator — Find out how much rent you can afford using the 30% rule, 50/30/20 budget, and a cashflow stress test. All three caps side by side so you see the trade-offs.

Mortgage Closing Cost Estimator — Estimate US mortgage closing costs before you buy. See itemized origination, appraisal, title, and prepaid fees with typical ranges and cash to close.

Mortgage Discount Points Break-Even Calculator — Find out if buying mortgage discount points is worth it. See the break-even month and net gain over your planned hold period. Points lose if you sell early.

Home Affordability Calculator — Find out how much house you can afford using the 28/36 DTI rule. Enter income, rate, and debts to get your max loan, price, and a DTI scenarios table. Supports Verifiable Calculation Certificates: pass certify=true to also receive a signed, independently verifiable re

Down Payment Calculator with PMI Threshold — Calculate your down payment amount, loan size, and PMI status instantly. See the dollar gap to 20% equity and compare multiple down payment scenarios.

Mortgage PITI Calculator — Calculate your full monthly PITI mortgage payment—principal, interest, property taxes, homeowners insurance, and PMI. Full amortization schedule included.

Balance Transfer Calculator — See how much a 0% balance transfer saves vs staying on your current APR. Enter the fee, promo months, and planned payment to find out if it is worth it.

HELOC Payment Calculator (Draw + Repayment) — Calculate your HELOC draw and repayment payments. See the payment shock when interest-only switches to fully amortized, plus total interest across both phases.

Debt Consolidation Calculator — See how your current debts compare against one new consolidation loan. A lower rate with a longer term can still cost you more — see the true lifetime numbers.

Credit Card Payoff Calculator — Find out how many months until your credit card is paid off — and how the minimum-payment trap costs you decades and multiples of your original balance.

Personal Loan Calculator with APR & Amortization — Calculate your personal loan monthly payment, total interest, and true effective APR including any origination fee. Full amortization schedule included. Supports Verifiable Calculation Certificates: pass certify=true to also receive a signed, indepe

Debt-to-Income (DTI) Ratio Calculator — Calculate your front-end and back-end debt-to-income ratio instantly. See how your debt load compares against the 36%, 43% QM, and 50% lender thresholds.

SaaS MRR Growth Projection Calculator — Model SaaS MRR growth with monthly compounding: add new revenue, subtract churn, apply expansion. See projected ARR and months to any revenue milestone.

CAC : LTV Ratio Calculator — Calculate Customer Lifetime Value, LTV:CAC ratio with poor/fair/good/excellent verdict bands, CAC payback months, and monthly gross profit per customer.

ROAS & Break-Even ROAS Calculator — Calculate ROAS and break-even ROAS instantly. Enter revenue, ad spend, and gross margin to see if your campaign is truly profitable — or just spending to spend.

Churn & Retention Rate Calculator — Calculate monthly and annual customer churn, revenue churn, and net revenue retention. Compounding conversion and implied average customer lifetime included.

CAC Payback Period Calculator — Calculate your CAC payback period with simple and discounted methods. Find the month your customer acquisition cost is fully recovered, plus a cumulative chart.

Burn Rate & Runway Calculator — Calculate startup burn rate and cash runway. Gross vs net burn, default alive or dead verdict, and month-by-month cash balance simulation with revenue growth.

Product Pricing Calculator — Set the right selling price for your product. Enter fully-loaded unit cost — materials, labor, overhead, and platform fees — then choose a target margin.

US Sales Tax Calculator (by State) + Reverse — Calculate US sales tax by state. Add or strip tax from any price. Select a state to prefill the rate; all 50 states included. 2025 base rates — local rates vary

Amazon FBA Profit Calculator — Calculate Amazon FBA net profit, margin, and ROI for any product. Enter price, COGS, and size tier to see the full fee breakdown and your break-even price.

Etsy Fee & Profit Calculator — Calculate Etsy fees, net proceeds, and break-even price for any listing. Fee breakdown always visible: listing $0.20, transaction 6.5%, payment 3%+$0.25.

Ecommerce Profit Margin Calculator — Calculate your true ecommerce profit margin including COGS, shipping, packaging, payment fees, and ad spend per unit. See contribution vs fully-loaded margin.

Solar Panel Savings Calculator — Estimate how much a rooftop solar system saves on your power bill: enter size, sun hours, cost, and any currently applicable credit to see yearly savings and payback.

Solar System Size Calculator (kW Needed) — Find the solar system size you need: enter yearly kWh usage, peak sun hours, and panel wattage to get the required kW and the number of panels it takes.

Appliance Electricity Cost Calculator — Work out what any appliance really costs to run. Enter its watts, hours per day, and your kWh rate to see the cost per day, month, and year at a glance.

EV Charging Cost Calculator — See what it really costs to charge your EV at home or on public chargers. Enter battery size, charge window, and rates for cost per charge and per mile.

Heat Pump vs Furnace Savings Calculator — Compare a heat pump against electric resistance or a furnace. Enter your heating need, COP, and rate to see yearly running cost, savings, and payback.

Home Battery Backup Size Calculator — Size a home backup battery. Enter your essential load in kW and hours of backup to get the kWh needed, how many battery units, and runtime at each load.

Car Affordability Calculator — How much car can you afford? Enter your monthly budget, APR, loan term, and down payment to see your max loan and car price, plus a 15%-of-income rule check.

Car Lease Payment Calculator (Money Factor) — Estimate your monthly car lease payment from the cap cost, residual, term, and money factor. See the depreciation and finance split, sales tax, and APR.

Lease vs Buy a Car Calculator — Compare leasing versus buying a car over the same time horizon. See each total cost, the difference, and true net cost per month once resale value is counted.

Car Depreciation Calculator — Estimate what your car will be worth in the years ahead. Enter price and depreciation rates to see a year-by-year value curve, total loss, and percent lost.

Cost Per Mile to Own a Car Calculator — See what your car truly costs to drive: enter yearly fuel, maintenance, insurance, depreciation, and financing interest or lease cost to get your real cost per mile driven.

Gas vs Electric Car Cost Calculator — Compare the yearly fuel cost of a gas car versus an electric car. Enter miles, MPG, and rates to see annual savings, break-even years, and 5-year totals.

Flooring Calculator (Boxes & Cost) — Figure out how many boxes of flooring to buy and what it costs. Enter room length, width, waste percentage, box coverage, and price per box for an estimate.

Tile Calculator (Tiles Needed) — Calculate how many floor or wall tiles you need. Enter room size, tile dimensions, and waste percentage to get total tiles, boxes to buy, and material cost.

Concrete Calculator (Cubic Yards & Bags) — Calculate how much concrete you need for a slab, footing, or pad. Enter length, width, and thickness to get cubic yards, cubic feet, and the exact bag count.

Drywall Sheet Calculator — Calculate how many drywall sheets you need for a room. Enter total wall and ceiling area, waste percent, and sheet size to get sheets, screws, mud, and tape.

Deck Board Calculator (Linear Feet & Boards) — Calculate how many deck boards you need. Enter deck length, width, board width, gap, and board length to get area, linear feet, board count, and total cost.

Fence Calculator (Posts, Panels, Rails) — Calculate fence materials fast: enter your run length, post spacing, and picket width to get exact posts, rails, and pickets, plus an optional total cost.

LLM API Cost Calculator (GPT-4o, Claude, Gemini) — Estimate monthly API costs for GPT-4o, Claude, and Gemini from tokens per request and volume. See input vs output cost split. Prices as of 2025 — verify.

Token Counter & Context-Window Fit Calculator — Estimate the token count of any text with the chars/4 words/0.75 heuristic, check if it fits 8k, 128k, 200k, or 1M context windows, and gauge API cost.

AI Build vs Buy Calculator (API vs Self-Host) — Compare the monthly cost of a hosted LLM API against self-hosting on your own GPUs. Find the break-even token volume and see which option is cheaper for you.

GPU VRAM Calculator (Model Size & GPU Fit) — Calculate the VRAM a large language model needs by parameter count and precision (fp16, int8, int4), then see which GPU it fits — from RTX 4090 to H100.

AI Tool ROI Calculator (Payback on Adoption) — Estimate the ROI and payback of an AI tool: enter hours saved per week, staff count, and cost to see monthly net savings, break-even months, and annual return.

AI Job Exposure Score — An AI job exposure score built from published research (Eloundou et al. 2023, O*NET, Goldman Sachs): estimate your task mix, not a prediction about you.

Salary to Hourly Calculator (and Back) — Convert an annual salary to an hourly wage or an hourly rate back to a yearly salary. Set your hours and weeks to see weekly, biweekly, and monthly pay too.

Overtime Pay Calculator (Time-and-a-Half) — Calculate overtime pay at time-and-a-half or a custom rate. Enter your hourly wage plus regular, overtime, and double-time hours for weekly and annual gross.

Pay Raise Calculator — Calculate your pay raise two ways: the nominal percentage increase and the real, inflation-adjusted raise, plus the annual and per-paycheck dollar gain.

PTO Accrual Calculator — Calculate how much paid time off you accrue each pay period from your annual PTO days, then project your future balance by pay date after the hours you've used.

1099 vs W-2 Rate Calculator — Compare a W-2 job to 1099 contract work: enter salary, employer FICA, benefits, and PTO to see the equivalent 1099 gross rate you need to break even fairly.

True Cost of an Employee Calculator — Calculate the true, fully loaded cost of an employee beyond base salary: add employer FICA, benefits, and overhead to see the total and its multiple of pay.

401(k) Employer Match Calculator — Calculate your 401(k) employer match: enter salary and contribution rate to see the free money you earn, your total yearly savings, and long-run growth.

Roth IRA Growth Calculator — See how a Roth IRA grows tax-free. Enter your annual contribution, expected return, and time horizon to project future value, total paid in, and growth.

CD Ladder Calculator — Build a CD ladder: split your savings across staggered-maturity CDs and see year-one interest, per-rung breakdown, and your blended APY across the whole ladder.

Coast FIRE Calculator — Find your Coast FIRE number: the amount you need invested today so it grows to your FIRE target by retirement with zero further contributions. Mind the gap.

DRIP Dividend Reinvestment Calculator — See how reinvested dividends compound your portfolio. Enter dividend yield, price growth, and yearly contributions to project future value and total growth.

Savings Drawdown Calculator — See how long your savings will last: enter your balance, monthly withdrawal, and expected return to find the months and years until the money runs out.

Retirement Monte Carlo Calculator — Estimate your retirement plan's success probability with 5,000 simulated Monte Carlo market paths, plus a fan chart of percentile balances at every age.

Mulch Calculator (Cubic Yards & Bags) — Calculate how much mulch you need for a garden bed or landscape. Enter area and depth to get cubic yards, cubic feet, and the exact number of bags to buy.

Topsoil Calculator (Yards & Weight) — Work out how much topsoil you need for a bed, lawn, or garden. Enter area and depth to get cubic yards, cubic feet, weight in tons, and the exact bag count.

Grass Seed Calculator — Calculate how much grass seed you need: enter your lawn area in square feet and the seeding rate to get pounds required and bags to buy for new or overseed.

Gravel & Aggregate Calculator (Yards & Tons) — Calculate how much gravel or aggregate you need for a driveway, path, or garden bed. Enter area and depth to get cubic yards, cubic feet, and tons by density.

Fertilizer Calculator (N-P-K Rate) — Work out how much fertilizer to spread: enter your lawn size, target nitrogen rate, and the bag N number to get pounds of product per feeding and per season.

One Rep Max (1RM) Calculator — Estimate your one-rep max from any set using the Epley and Brzycki formulas, then read a full percentage-of-1RM table to set training loads for every lift.

Body Fat Percentage Calculator (Navy Method) — Estimate your body fat percentage with the US Navy tape-measure method. Enter your sex, height, neck, waist, and hip to see body fat and lean body mass.

Ideal Weight Calculator (4 Formulas) — Estimate ideal body weight from your height and sex using four classic formulas (Devine, Robinson, Miller, Hamwi) and see the healthy range, not one number.

Calories Burned Calculator (MET-Based) — Calculate calories burned by activity with the MET formula: enter weight, minutes, and activity to estimate energy spent, and compare exercises side by side.

Heart Rate Zone Calculator — Calculate your five heart rate training zones from your age using the 220 − age or Tanaka formula, with an optional Karvonen resting heart rate refinement.

Calorie Deficit Calculator (Goal Weight by Date) — Set a goal weight and a target date to see the daily calorie deficit you need, your projected weekly loss rate, and whether the pace is safe or too fast.

Recipe Scaler / Serving Size Calculator — Scale any recipe up or down: enter the original and desired servings, and this tool multiplies every ingredient by the exact ratio so amounts stay balanced.

Baking Pan Size Conversion Calculator — Convert a recipe between round, square, and rectangular baking pans. Scale batter by pan area, not diameter, to see the exact ratio and bake-time guidance.

Pizza Dough Calculator (Baker's Percentage) — Calculate pizza dough by baker's percentage: enter ball count, weight, and hydration to get exact flour, water, salt, and yeast weights for your batch.

Turkey Cooking Time & Thaw Calculator — Estimate turkey roasting time by weight, plus refrigerator and cold-water thaw times. Stuffed or unstuffed, always cook to 165°F verified with a thermometer.

Recipe Cost & Cost-Per-Serving Calculator — Cost out any recipe in seconds: enter ingredients, quantities, and unit prices to get total cost, cost per serving, and a suggested menu price by food cost.

Brine Calculator (Salt Ratio by Weight) — Calculate salt and sugar for wet or dry brines by weight: enter water volume or meat weight and a salt percentage to get exact grams and a strength chart.

Depth of Field & Hyperfocal Calculator — Calculate depth of field and hyperfocal distance from focal length, aperture, and subject distance. See the near and far limits of sharp focus in meters.

Crop Factor / Equivalent Focal Length Calculator — Convert focal length to a full-frame equivalent by crop factor. Enter focal length, aperture, and sensor to get equivalent focal, aperture, and field of view.

Print Resolution & Max Print Size Calculator — Find the largest quality print from your photo pixels, or the DPI a chosen print size lands at. Enter pixel size and a target size or DPI to check the fit.

Time-Lapse Calculator (Interval, Clip, Storage) — Plan a time-lapse: enter shoot length, shot interval, playback fps, and file size to see how many frames you shoot, your clip length, and storage needed.

Aspect Ratio Calculator (Resize & Crop) — Simplify an aspect ratio and resize while keeping it. Enter width and height to get the ratio like 16:9, then a new width to solve the matching height.

Dog Age Calculator (Human Years, Size-Adjusted) — Convert your dog age into human years the AKC way, adjusted for body size — not the old myth of multiplying by seven. Enter age and size for a real estimate.

Dog & Cat Food Portion Calculator — Estimate how much to feed a dog or cat from ideal weight and activity using the vet RER formula. Enter weight and food calories to get daily cups to serve.

Puppy Adult Weight Predictor — Predict your puppy adult weight from its current weight and age in weeks, with a size-class note. Enter the numbers to see the grown-up size to expect.

Pet Cost Calculator (First-Year & Lifetime) — Add up the true cost of a pet: first-year and lifetime. Enter monthly food, vet, insurance, and supplies plus setup cost to see what it really adds up to.

Aquarium Volume & Stocking Calculator — Work out your fish tank volume and stocking capacity. Enter length, width, and height in inches to get gallons, litres, inch-of-fish, and heater wattage.

Required Savings Calculator — Find the monthly savings needed to reach a goal: three deterministic return scenarios plus an inverse Monte Carlo rate sized for your chosen success odds.

Purchase Impact Calculator — See the true cost of any purchase: what the price would grow to if invested, how many days of work it represents, and how far it pushes back your FIRE date.

Hire vs Outsource Calculator — Compare the fully loaded cost of an in-house hire against outsourcing to an agency or freelancer, with a break-even hours line showing when hiring wins.

Global Hiring Cost Calculator — Compare the annual cost of a US W-2 employee against an international contractor or an EOR hire, including employer taxes, benefits, and platform fees.

AI Automation Payback Calculator (Process ROI) — Estimate the payback of automating a process with AI: task volume, time saved, review effort, and API costs give net monthly savings and break-even months.

LLC vs Sole Proprietor Calculator — Compare a sole proprietorship with an LLC: formation and annual state costs, self-employment tax on both, and the estimated savings of an S-corp election.

Pricing Strategy Calculator — Model a price change before you commit: see the maximum volume you can lose and stay profitable, plus predicted demand and profit at a chosen elasticity.

Lead Gen Budget Calculator — Work out your lead generation budget: leads needed for a customer goal, the implied CAC against your LTV target, and the maximum cost per lead to pay.

LLM Self-Host vs API Cost Calculator — Find the monthly token volume where self-hosting an LLM on rented GPUs beats paying per token for an API. Compare costs, GPUs needed, and breakeven point.

Fine-Tuning Cost Calculator — Estimate what a fine-tuning run costs: GPU-hours for a self-managed cluster versus per-token managed API pricing, with wall-clock time and the cheaper path.

RAG Cost Calculator — Estimate what a RAG pipeline costs: one-time corpus embedding, monthly vector storage, and per-query LLM generation from verified 2026 provider prices.

AI Agent Cost Calculator — See what an AI agent really costs per successful task: steps, tokens, model pricing and success rate turn dashboard cost per run into the true unit cost.

Prompt Caching Savings Calculator (LLM API Costs) — Estimate how much prompt caching cuts your LLM API bill: monthly input tokens, cacheable share, and hit rate give per-model savings, cache writes included.

LLM Throughput & GPU Sizing Calculator — Estimate how many GPUs your LLM needs: concurrent users and target tokens per second become cluster size, monthly cloud cost, and real utilization at load.

Tiered Commission Calculator (USD) — Calculate tiered sales commission in USD: a base rate up to a threshold, a higher rate above it, plus any settlement adjustment. See the exact per-tier math. Supports Verifiable Calculation Certificates: pass certify=true to also receive a signed, independently v