FeaturedUsing an Online Calculator Properly: Rules, Functions and Common Mistakes
How does a calculator actually work? This guide explains order of operations, brackets, percent, memory, rounding and scientific functions — with plenty of examples.
Start calculating right away — by click or keyboard. With correct order of operations, percent, brackets and scientific functions.
Keyboard: digits, + − * / ^ ( ) . % · Enter = result · Backspace = delete · Esc = clear all · s/c/t = sin/cos/tan · r = √ · p = π
Your calculations appear here. The last 20 are kept — only locally in your browser.
For many everyday questions there is a dedicated calculator that handles the formula for you — from percentages to gross-to-net pay to wall area. (110 calculators)
Email history
Was the calculator helpful?
Kaffee ausgeben ☕Calculate percentages with the working: amount, base value, change
Order of operations, percent, roots, powers and scientific functions explained clearly
FeaturedHow does a calculator actually work? This guide explains order of operations, brackets, percent, memory, rounding and scientific functions — with plenty of examples.
Brackets before powers before multiplication before addition: the order of operations with examples, memory aids and the classic pitfalls.
Why does 200 + 10% give 220 on a calculator? The logic of the percent key, discounts, mark-ups and VAT step by step.
What do DEG and RAD mean, when do you need ln instead of log and what are sin⁻¹ and n! for? The key functions at a glance.
Square, exponent, square root and nth root: how to calculate powers and roots on a calculator — including negative and fractional exponents.
Calculate percentages: base value, percentage, change, markup & discount
Calculate now →Add, subtract, multiply, divide, simplify and convert fractions
Calculate now →Proportional, inverse and compound rule of three with step-by-step solution
Calculate now →