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THE SUMFIZZ LIBRARY

Everyday arithmetic calculators

Explore 25 free tools for everyday arithmetic. Find percentage of a number, percentage change, percentage difference and more. Each calculator explains its inputs and method, with examples you can try using your own numbers.

THE SUMFIZZ LIBRARY

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25 calculators

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Percentage of a number

A percentage is a fraction of 100.

Everyday arithmetic

Percentage change

Use the original value as the denominator.

Everyday arithmetic

Percentage difference

Percentage difference uses the mean of the two values as its baseline, rather than treating either value as the original.

Everyday arithmetic

Reverse percentage

Divide the final amount by one plus the percentage change.

Everyday arithmetic

Percentage points

Subtract percentages for percentage points.

Everyday arithmetic

Discount and sale price

Apply the discount to the original price.

Everyday arithmetic

Successive discounts

Apply discounts in sequence.

Everyday arithmetic

Tip and bill split

The tip applies to the entered bill.

Everyday arithmetic

Unequal bill split

Split shared charges evenly and apply the same tip percentage to each resulting share.

Everyday arithmetic

Unit price comparison

Use the same quantity unit for both packs.

Everyday arithmetic

Proportional allocation

Each allocation equals the total multiplied by its weight divided by all weights combined.

Everyday arithmetic

Ratio simplifier

Divide every term by the greatest common divisor.

Everyday arithmetic

Ratio scaling

Distribute the required total in proportion to the entered ratio.

Everyday arithmetic

Average calculator

The arithmetic mean is the sum divided by the number of values.

Everyday arithmetic

Weighted average

Multiply each value by its corresponding weight, add the products, then divide by the sum of the weights.

Everyday arithmetic

Rounding calculator

Rounds using JavaScript number formatting.

Everyday arithmetic

Significant figures

Significant figures count meaningful digits starting with the first nonzero digit.

Everyday arithmetic

Fraction arithmetic

Use exact integer fractions for the selected operation.

Everyday arithmetic

Mixed number converter

For this non-negative mixed number, multiply the whole part by the denominator and add the numerator.

Everyday arithmetic

Decimal to fraction

Converts a finite decimal string exactly, including a leading minus sign.

Everyday arithmetic

Coin flipper

Each flip uses one bit from the browser’s cryptographic random generator.

Everyday arithmetic

Random name picker

Selects one entry uniformly using rejection sampling over browser-generated random integers.

Everyday arithmetic

Order of operations

Supports numbers, parentheses and + − × ÷ ^.

Everyday arithmetic

Change-making calculator

Uses standard GBP coin and note denominations, rounding both entered amounts to pennies.

Everyday arithmetic

Expense settlement

Enter people in the same order in both lists.

Everyday arithmetic