Math & Everyday Calculators
Percentage, fraction, ratio, GPA, grade, tip and random-number tools for quick everyday math.
free tools · no sign-up · works in your browser
Coin Flip — Heads or Tails
Flip a virtual coin and get heads or tails instantly — with a history of your last flips.
Percentage Calculator
Work out what X% of a number is — for discounts, tips, tax, marks or any share of a total.
What Percentage Is X of Y Calculator
Find out what percentage one number is of another.
Average Calculator
Find the average (mean), sum, count and median of up to five numbers — leave the optional fields blank for fewer values.
Margin Calculator
Calculate profit margin and markup percentage from a selling price and cost — for pricing any product or service.
Prime Number Checker
Check whether a number is prime and see its full prime factorization.
Dice Roller
Roll up to 10 virtual dice — d4, d6, d8, d10, d12, d20 or d100 — perfect for board games and D&D.
Percent Off Calculator
Quickly work out the sale price and how much you save when an item is a given percent off.
Discount Calculator
Calculate the sale price and amount saved after a percentage discount.
Tip Calculator
Work out the tip and total bill, and split it evenly between any number of people.
Ratio Calculator
Simplify a ratio to its lowest terms and express it as a decimal and a percentage.
Reverse Sales Tax Calculator
Back out the pre-tax price and the sales tax amount from a tax-inclusive total — handy for receipts and expense reports.
Square Footage Calculator
Calculate the area of a room or space in square feet from its length and width, with conversions to square yards, square meters and acres.
Square Root Calculator
Find the square root, square and cube root of any number instantly.
Percentage Increase / Decrease Calculator
Calculate the percentage increase or decrease between two numbers.
LCM & GCF Calculator
Find the least common multiple (LCM) and greatest common factor (GCF/HCF) of two numbers.
Yes or No Wheel
Can't decide? Ask the wheel — get an instant YES or NO (with an optional Maybe) and settle it.
Random Name Picker
Paste a list of names or options and pick one at random — fair draws for giveaways, teams and classrooms.
Modulo Calculator
Calculate a mod b — the remainder after division — with the floor quotient shown too.
Picking the right percentage or everyday calculator
Percentage questions sound alike but use different formulas, which is why there are several calculators for them. Pick the one that matches how the question is phrased.
- Percentage Calculator: what is X% of Y, such as a share of a bill or a commission on a sale.
- What Percentage Is X of Y Calculator: the reverse question, such as a test score as a percentage of the total marks.
- Percentage Increase / Decrease Calculator: the change from an old value to a new one, such as a price rise. A rise followed by a fall of the same percentage does not bring you back to the start, because the second percentage applies to a different base.
- Discount Calculator: the sale price after a percentage off, and how much you save.
Tip Calculator works out the tip and the total, and splits the bill evenly between any number of people.
Random picks
When a choice needs to be fair rather than calculated, Coin Flip — Heads or Tails settles a two-way decision, Dice Roller covers board games, and Random Name Picker draws a winner or a presenter from a list you paste in.
Every calculation runs in your browser and updates as you type.