Percentages and tax

Percentage increases, discounts, VAT in and VAT out — the arithmetic everybody thinks they know until a 20 per cent rise followed by a 20 per cent fall does not return them to where they started.

Loans and credit Budgeting and saving Percentages and tax Health calculators Everyday money

3 guides

A paper invoice, pen and small calculator on a wooden desk under soft natural light.

Adding and Removing VAT: A Plain Guide for Online Calculators

Learn how to add and remove VAT correctly: why you divide by 1 + rate, the four-unit mistake, and the margin-versus-markup trap on the same invoice.

Percentages and tax 8 min read

A supermarket shelf showing two different pack sizes of the same product with price labels underneath.

Sale Maths: Online Calculators for Stacked Discounts and Real Savings

Learn how retailers phrase discounts so you can check the real saving instantly with online calculators and unit-price comparisons.

Percentages and tax 8 min read

A wooden desk with a notebook, a basic calculator, a pen and a coffee cup, seen from above in soft daylight.

Percentage Calculations Explained: Online Calculators and Four Sums

Learn the four percentage calculations everyone confuses, with worked examples and formulas so you pick the right base every time.

Percentages and tax 8 min read