Free Online Calculators
Finance, health, time, date, construction, and math calculatorsโorganized by topic so you find the right tool fast.
Each calculator below is its own page with a short how-to, formula notes where relevant, and links to related tools (for example loan vs mortgage or BMI vs body-fat). Most run entirely in your browser, so amounts you type stay on your device.
Not sure where to start? Popular picks include mortgage, percentage, BMI, tip, and loan payment calculators. For background reading, see our percentage guide or the About ToolsOnline page.
Finance Calculators
Money, tips, loans, and savings โeveryday financial math.
Health Calculators
Body metrics, calories, and sleep cycles.
Time & Date Calculators
Add time, count days, and calculate age.
Home Calculators
Floor area, room volume, and watts.
Everyday Calculators
Steps in a mile, and baseball earned run average.
Math & Education Calculators
Percentages, grades, and school math.
Related guide: How to calculate percentages
Calculator FAQs
Which calculator should I use for a home loan?
Start with the mortgage calculator for payment and amortization. Comparing a new rate on an existing loan? Use the refinance calculator.
Are these calculators free?
Yesโno signup, no download. Open a tool and enter your numbers.
Can I use results for taxes or medical decisions?
Use them for estimates and learning. For filing, lending, or clinical choices, verify with a qualified professional.