About PercentGo

PercentGo is a set of free calculators for the percentage questions people ask every day: a discount in a shop, VAT on an invoice, a pay rise, a test score, a profit margin.

How we keep the numbers right

Every calculator runs on one tested calculation module. Before each release an automated test suite checks known answers — percentages of numbers, reversed percentages, stacked discounts, VAT in and out at each country’s rates, weighted averages and margins.

A calculator, not financial advice

Results are rounded for display only. Tax rates and prices depend on your country and situation; check official sources before you rely on a number for an invoice or a tax return.