Free Online Calculators for Finance, Health, Math, Conversions & More
47 calculators with instant results, the formula behind every answer and worked examples you can check.
Featured calculators
per month on a $320k loan
Mortgage Calculator
Monthly payment with tax, insurance and total interest.
for 70 kg at 175 cm
BMI Calculator
Body mass index and a healthy weight range for your height.
is 15% of 80
Percentage Calculator
Percent of a number, percent share and percent change.
Currency Converter
Convert between major world currencies.
Scientific Calculator
Trigonometry, logarithms, powers and roots with a keypad.
Browse by category
Every calculator, grouped the way you'd look for it.
Financial Calculators15 tools
Plan mortgages, loans, savings and investments with clear payment breakdowns.
Health & Fitness Calculators11 tools
Estimate body measurements, daily energy needs, pregnancy dates and training zones.
Math Calculators11 tools
Solve percentages, fractions, statistics and geometry, with the working shown.
Conversion Calculators10 tools
Unit conversion made simple: convert metric and imperial units, temperatures, currencies and data sizes instantly.
Most popular
Understand the numbers, not just the answer
Each calculator explains how it works, shows the formula it uses and walks through an example. Our guides go further, covering the ideas behind mortgages, interest, body measurements and units.
Read the guidesHow to read an amortization schedule, row by row
A plain-English walkthrough of a real 30-year amortization schedule: what each column means, when principal overtakes interest, and what extra payments change.
48 vs. 60 vs. 72-month car loan: what each term really costs
Monthly payment vs. total cost on 48, 60, 72 and 84-month car loans, the negative equity trap, and when a longer term can still make sense.
How much to invest each month to reach $1 million
The monthly amount needed to reach $1 million by age and return, what fees and inflation do to it, and how existing savings change the plan.
How to calculate the square footage of a room
Measure any room in square feet, including L-shaped and irregular spaces, convert to square meters, and work out how much flooring to order.
Frequently asked questions
Are the calculators free to use?
Yes. Every calculator is free, works in your browser and needs no account.
How accurate are the results?
Calculations use standard published formulas and are accurate for the numbers you enter. Real-world figures such as loan offers or health measurements can differ, so treat results as estimates.
Do you store the numbers I enter?
No. Calculations run on your device and the values you type are not sent anywhere.
Can I use the calculators on my phone?
Yes. Every page is built for small screens first, with number keyboards on mobile and large touch targets.
Can I suggest a new calculator?
Yes. Use the contact page to tell us what you need. Construction, business, tax and crypto calculators are already planned.