1001 Pro Calculators and Tools

1001 Pro Calculators and Tools puts 1,001 calculators across 28 categories into one Android app, with no adverts on any tier and full offline use. It covers finance, tax, mortgages and loans, health and fitness, engineering, construction, conversions, maths and everyday sums. Every result shows its working, and the arithmetic is exact rather than rounded, tested against published worked examples. 250 calculators are free permanently, with no account or sign-in, and nothing entered in the app is sent anywhere.