Basic Calculator
Everyday arithmetic — add, subtract, multiply and divide with chained operations, percentages, square roots, squares and reciprocals, a memory register (MC / MR / M+ / M−), and a running history tape.
Built by Suhaib Hassan. Our methodology.
Operates like a physical calculator: each operator is applied left to right as you enter it (not full algebraic order of operations) — the same convention as every handheld calculator.
Fast everyday arithmetic with a memory register and a visible history tape, so you can check your last few steps.
Calculator
Use the calculator to the left — every completed calculation appears here and in the history tape below.
History tape
Every calculation you complete, most recent first.
How the buttons work
- Chain operations: each operator applies immediately to the running total, left to right — like every physical calculator, not full algebraic PEMDAS (so 2 + 3 × 4 gives 20, not 14; use = after each step if you want to control the order yourself).
- √, x², 1/x: apply instantly to the number currently on screen.
- MC / MR / M+ / M−: clear, recall, add-to, or subtract-from the memory register.
- C clears the current entry only; AC clears everything, including memory-pending operations.
By Suhaib Hassan · Reviewed 29 September 2026 · How CalculatePilot verifies formulas →
Frequently asked questions
Why does 2 + 3 × 4 give 20 instead of 14?
Simple calculators evaluate strictly left to right as you press keys — 2+3 is computed as soon as × is pressed (=5), then 5×4=20. Scientific calculators and algebra follow order of operations (PEMDAS) instead, which would give 2+(3×4)=14. Use our Scientific Calculator for expression-based PEMDAS evaluation.
What does the % key do?
It divides the number currently on screen by 100 — so 50 % becomes 0.5, ready to use in a further calculation (e.g. for "20 × 15 %" to find 15% of 20).
What's the difference between C and AC?
C (Clear) resets only the number you're currently typing, keeping any pending operation and running total. AC (All Clear) resets everything back to zero, including memory-pending calculations (but not the M register).
Can I use negative numbers and decimals?
Yes — use ± to flip the sign of the current entry, and the decimal point key for fractional values, exactly as on a physical calculator.
How precise is the arithmetic?
It uses IEEE 754 double-precision floating point (about 15–17 significant decimal digits) — the same standard used by virtually all calculators, spreadsheets and programming languages.
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