GCD & LCM calculator
ClientEnter two whole numbers to get their greatest common divisor and least common multiple—useful for fraction reduction and scheduling problems.
GCD and LCM together
The greatest common divisor (GCD) uses the Euclidean algorithm on BigInt values; the least common multiple (LCM) is (a / GCD) × b. Both accept non-negative integers—use Math evaluator for general expressions or Percentage calculator for ratio word problems.
- GCD
- 6
- LCM
- 144
Nearby workflows on Toolcore
- Integer base converter — when you need binary or hex views of the same values.
- Roman numerals — for classical notation instead of gcd/lcm arithmetic.
Common use cases
- Reduce ratio pairs before coding a gear or pulley problem.
- Find a common cycle length for two repeating events.
- Check homework GCD/LCM steps quickly.
Common mistakes to avoid
Negative numbers
Only non-negative integers are accepted—use absolute values first.
FAQ
How large can inputs be?
Arbitrary-precision BigInt is used—very large integers are supported until the browser runs out of memory.
Common search terms
Phrases people search for that match this tool. See the full long-tail keyword index.
- gcd lcm calculator online
- greatest common divisor least common multiple
- euclidean gcd lcm tool browser
- find gcd and lcm of two numbers
More tools
Related utilities you can open in another tab—mostly client-side.
Integer base converter
ClientWhole numbers in radices 2–36: binary, octal, decimal, hex (optional 0x), custom bases; BigInt-sized strings, local only.
Roman numerals converter
ClientArabic integers 1–3999 ↔ classical Roman letters (IV IX XL XC CD CM)—canonical spelling only, in browser.
Percentage calculator
ClientPercent of a value, ratio to percent, and percent change—no server round-trip.
Math expression evaluator
ClientEvaluate basic + − × ÷ arithmetic with parentheses in your browser—no variables.