15 free tools
Free Online Calculators
Quick calculators for the everyday sums that are easy to get slightly wrong in your head. Enter your numbers and the answer updates instantly.
Calculators
Calculate a percentage of a number, percentage change and what percent one value is of another.
Find your age in years, months and days from a date of birth.
Calculate sale price, discount amount and final savings.
Calculate Body Mass Index from height and weight.
Simplify a ratio and find the missing value when you scale it up or down.
Find the average, sum and count of a list of numbers.
Generate random whole numbers in any range, with or without duplicates.
Count the days between two dates, or add and subtract days, weeks, months or years.
A countdown timer with presets, pause and resume, and an optional alarm sound.
A stopwatch with lap times and millisecond display that stays accurate in background tabs.
See how savings grow with compound interest, from annual to daily compounding.
Estimate the monthly payment, total cost and total interest of a fixed-rate loan.
Calculate a GPA on the 4.0 scale from course grades and credits.
Find the hours, minutes and seconds between two times, even across midnight.
Work out the tip, the total and each person’s share when splitting a bill.
About these calculators
Use the Percentage Calculator to work out a share of a total, the percentage change between two values, or what percent one number is of another. When shopping, the Discount Calculator turns a percentage off into a sale price and the amount you save. The Average Calculator finds the mean, sum and count of a list, and the Ratio Calculator simplifies ratios and scales them, for example to keep a 16:9 aspect ratio. For money, the Compound Interest Calculator shows how savings grow, the Loan Calculator estimates a fixed-rate monthly payment and the Tip Calculator splits a bill fairly.
For dates, the Age Calculator gives an exact age in years, months and days, and the Date Calculator counts the days between two dates or adds weeks and months to one. The Online Timer and Stopwatch handle countdowns and lap times, and stay accurate when you switch to another tab. The Time Duration Calculator finds the hours and minutes between two clock times, even across midnight. A GPA Calculator, BMI Calculator and Random Number Generator round out the set.
Each calculator shows a worked example and explains its formula, so you can check how a result was reached. They are meant for everyday estimates, not financial, legal or medical advice.
Frequently Asked Questions
How accurate are these calculators?
They use standard JavaScript number arithmetic, which is accurate for everyday values. Results are rounded for display, so very large numbers or long decimals may show small rounding differences.
Do the calculators save my numbers?
No. Values stay in the page while you use it and are not sent to a Usevanta server. Refreshing the page resets them.
Can I use the calculators on my phone?
Yes. The calculators work in modern mobile browsers, and number fields open a numeric keyboard where the browser supports it.