Every calculator you need, beautifully simple.
Mortgages, tax, BMI, pregnancy, fractions, subnets and more — accurate results in seconds, on any device.
Financial Calculators
View allMortgage Calculator
Monthly home loan payment with taxes, insurance and a full amortization schedule.
Loan Calculator
Repayments, total interest and schedule for any personal or business loan.
Auto Loan Calculator
Car loan payment including trade-in, deposit, sales tax and fees.
Interest Calculator
Simple or compound interest on a balance with optional regular deposits.
Payment Calculator
Find the payment for a set term, or the term for a set payment.
Retirement Calculator
Project your retirement savings and see if they will last.
Amortization Calculator
Full monthly amortization schedule with extra repayments.
Investment Calculator
Grow an investment with regular contributions and see the yearly breakdown.
Inflation Calculator
Future cost and lost purchasing power from inflation.
Finance Calculator
Time value of money: solve for FV, PV, payment, periods or rate.
Income Tax Calculator
Income tax and take-home pay for Australia, Sri Lanka and the USA.
Compound Interest Calculator
See how compounding and monthly deposits grow your savings.
Salary Calculator
Convert pay between hourly, daily, weekly, monthly and yearly.
Interest Rate Calculator
Find the real interest rate from the loan amount and payment.
Sales Tax Calculator
Add or remove sales tax, GST or VAT from a price.
Fitness & Health Calculators
View allBMI Calculator
Body Mass Index with WHO category and healthy weight range.
Calorie Calculator
Daily calories to maintain, lose or gain weight.
Body Fat Calculator
Estimate body fat % with the U.S. Navy tape-measure method.
BMR Calculator
Basal metabolic rate with three scientific equations.
Ideal Weight Calculator
Ideal body weight from four classic formulas.
Pace Calculator
Running pace, finish time or distance — with race predictions.
Pregnancy Calculator
How far along you are, trimester and key milestones.
Pregnancy Conception Calculator
Estimate when conception happened from a due date or last period.
Due Date Calculator
Estimated due date from last period, conception or IVF transfer.
Math Calculators
View allScientific Calculator
Full scientific calculator with trig, logs, powers and history.
Fraction Calculator
Add, subtract, multiply and divide fractions and mixed numbers.
Percentage Calculator
Percent of, percent change, increase/decrease and more.
Random Number Generator
Secure random numbers in any range, with or without repeats.
Triangle Calculator
Solve any triangle from three sides or angles, with a diagram.
Standard Deviation Calculator
Standard deviation, variance, mean, median and more.
Other Calculators
View allAge Calculator
Exact age in years, months and days, plus next birthday.
Date Calculator
Days between dates, or add/subtract days, weeks, months.
Time Calculator
Add or subtract days, hours, minutes and seconds.
Hours Calculator
Weekly timesheet: hours worked, breaks, overtime and pay.
GPA Calculator
Grade point average on a 4.0 scale with credits.
Grade Calculator
Weighted course grade and the final exam score you need.
Concrete Calculator
Concrete volume for slabs, footings and columns, plus bags.
Subnet Calculator
IPv4 network, broadcast, host range and mask from CIDR.
Password Generator
Strong, random passwords generated securely on your device.
Conversion Calculator
Convert length, weight, temperature, area, volume and more.
Why people use CalcPrime
Instant results
Answers update as you type — no submit buttons, no page reloads.
Private by design
Every calculation runs on your device. Nothing you enter is sent or stored.
Web + Android app
Use it in any browser or install the Android app, which also works offline.
Trusted formulas
Standard published formulas and 2026 tax tables, with the method explained.