The modulo operation answers one question: after dividing evenly, what is left over? Fourteen divided by 4 gives 3 with 2 left over, so 14 mod 4 = 2. Programmers write it as the percent sign — 14 % 4 — and use it constantly: checking whether a number is even (n % 2 == 0), wrapping an index around an array, or dealing cards in rotation to players. It is division's overlooked sibling, and it shows up far more often than the quotient does.

Everyday cycles are modulo problems in disguise. A parking garage charging in 24-hour cycles, a work schedule rotating every 14 days, or a "every 3rd item free" sale all ask for remainders. Even telling time is modular: minutes wrap mod 60, hours mod 12. This calculator performs the full division breakdown: enter the dividend and divisor, and it reports the quotient, the remainder (a mod b), and the pieces in between — everything you need to verify code logic, split rotations fairly, or check arithmetic homework.

With the pre-filled defaults — Dividend (a) 17, Divisor (b) 5 — the Modulo Calculator returns Quotient 3, Remainder (a mod b) 2. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.