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249 free calculators
you can trust.
Financial, health, math and everyday tools — nothing installed, nothing logged. Every result computed entirely in your browser.
- 01
Mortgage
Calculate your monthly mortgage payment, total interest, and see a full amortization schedule. Free, accurate, and runs in your browser.
Calculate → - 02
BMI
Calculate your Body Mass Index (BMI) from height and weight, in metric or imperial units. See your WHO weight category and healthy weight range.
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Percentage
Calculate X% of Y, percentage change between two values, or percentage difference. Three modes in one calculator.
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Tip
Calculate the exact tip and total for any bill. Choose 10%, 15%, 18%, 20%, or enter a custom percentage — instant results with no guessing.
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- 69 tools
Financial
Mortgage, loans, savings and retirement. Accurate tools for real money decisions.
Explore → - 62 tools
Health
BMI, BMR, body composition and fitness. Health estimates that stay in your browser.
Explore → - 47 tools
Math
Percentages, statistics, geometry and number theory. All computed locally.
Explore → - 71 tools
Other
Unit converters, date & time, everyday math, home improvement and developer tools.
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BMI Explained: What Body Mass Index Measures and Its Limitations
Learn what BMI is, how it's calculated, what the WHO categories mean, and where BMI falls short for athletes, older adults, and diverse populations.
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The Power of Compound Interest: How It Grows (and Costs) Your Money
Compound interest grows money exponentially by earning returns on prior returns. See the formula, a worked example, and how it affects savings and debt.
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How Mortgage Payments Work: Principal, Interest & Amortization Explained
A plain-English breakdown of the mortgage payment formula, how amortization shifts your monthly costs over time, and a worked example on a $400,000 loan.
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How Much Should You Save for Retirement? A 401(k) Planning Guide
How much to save for retirement: benchmarks by age, 401(k) contribution rules, employer match, and a worked projection for your retirement balance.