Guides
Step-by-step answers about percentages, discounts and tax, with every number worked out by our calculators.
2026-10-22How to Calculate a Percentage: Formulas, Examples and TablesHow to calculate a percentage of a number, what percent one number is of another, and the original number from a percentage — three formulas with worked examples and tables.Read the guide →2026-10-22Percentage Increase Formula: How to Calculate Percent ChangeThe percentage increase and decrease formula with worked examples, a percent change table, percentage points, reversing a change and compound changes over several years.Read the guide →2026-10-22Percent Off Chart: Sale Prices from 5% to 90% OffPercent off chart with sale prices for common discounts, how to work out a discount in your head, double discounts like "extra 20% off", and the percent off between two prices.Read the guide →2026-10-22How to Calculate VAT: Add and Remove 20% VATHow to add VAT to a net price and remove VAT from a gross price at 20% and 5%, why you divide by 1.2 instead of taking 20% off, the 1/6 rule, and VAT tables.Read the guide →