Free online calculators you can trust
40 fast, accurate calculators for money, health, math and dates — each with the formula explained and worked examples.
💰 Finance
All finance calculators →Loan Calculator
Monthly payment, total interest and amortization schedule.
Mortgage Calculator
Full monthly housing payment with taxes, insurance and PMI.
Compound Interest Calculator
Growth of savings with compounding and contributions.
Retirement Calculator
Project your nest egg and retirement income.
Auto Loan Calculator
Car payment with trade-in, tax and fees.
Savings Goal Calculator
Monthly saving needed to reach a goal.
Credit Card Payoff Calculator
Months to debt-free and total interest.
Debt-to-Income Ratio Calculator
Front-end and back-end DTI for lenders.
Inflation Calculator
Future cost and lost purchasing power.
ROI Calculator
Total and annualized return on investment.
Simple Interest Calculator
Interest on principal without compounding.
Salary to Hourly Calculator
Annual salary ↔ hourly, weekly and monthly pay.
House Affordability Calculator
Maximum home price by income and debts.
CAGR Calculator
Compound annual growth rate between two values.
❤️ Health & Fitness
All health & fitness calculators →BMI Calculator
Body mass index with healthy weight range.
Calorie Calculator
Daily calories to maintain, lose or gain weight.
BMR Calculator
Calories burned at complete rest.
Body Fat Calculator
Body fat % from tape measurements.
Ideal Weight Calculator
Ideal body weight by four clinical formulas.
Macro Calculator
Daily protein, carbs and fat in grams.
Due Date Calculator
Estimated due date and current week of pregnancy.
Pace Calculator
Running pace, finish time or distance.
➗ Math
All math calculators →Percentage Calculator
Three percentage problems, solved with steps.
Percentage Change Calculator
Percent increase, decrease and difference.
Fraction Calculator
Fraction arithmetic with simplified results.
Standard Deviation Calculator
Standard deviation, variance, mean and median.
Quadratic Equation Calculator
Roots, discriminant and vertex with steps.
GPA Calculator
Semester and cumulative GPA on a 4.0 scale.
Final Grade Calculator
Score needed on the final exam.
Ratio Calculator
Simplify ratios and solve proportions.
🔁 Conversions
All conversions calculators →📅 Date & Time
All date & time calculators →Age Calculator
Exact age and days to next birthday.
Days Between Dates Calculator
Days, weeks and months between two dates.
Date Calculator
Add or subtract time from a date.
Time Duration Calculator
Hours and minutes between two times.
Hours Worked Calculator
Weekly timesheet with breaks and pay.
Business Days Calculator
Working days between dates, excluding holidays.
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Tested for accuracy
Every calculator is checked against known values and published formulas before it goes live.
Formulas explained
See exactly how each result is calculated, with worked examples you can follow.
Private by design
Calculations run in your browser. What you type is never sent to our servers.
Fast on any device
Lightweight pages that load instantly and work perfectly on phones.