Modulus Calculator
An = x mod(C)
Modular Arithmetic at a Glance
The modulo operation returns the remainder after division: a mod b is what is left when a is divided by b as many whole times as possible. 17 mod 5 is 2, because 5 fits into 17 three times (15) and 2 is left over. The same idea powers a huge range of everyday systems - clock arithmetic, weekdays, cyclic gear indexing, checksums, and the number theory behind modern cryptography.
The Remainder Table for an
Instead of showing just the final answer, the calculator walks through every step of the exponentiation. For each power from 1 up to n it lists the computation a^i, subtracts the nearest lower multiple of c, and prints the remainder in modular notation - for example 3² = 9, 9 - 7 = 2, so 3² ≡ 2 mod 7. The final row is highlighted so the result of an mod c is easy to spot, and the whole table is worth keeping for homework, proofs, or documentation.
Where Modulo Is Used in Engineering and Programming
In programming, the remainder operator cycles an index (i % n), detects even and odd values, and validates checksums such as ISBN and credit-card numbers. In mechanics, modular arithmetic describes rotary indexing: a fixture with 12 stations advanced 5 steps each cycle lands on predictable positions, and gear-tooth meshing repeat patterns modulo the tooth count. Because the tool computes an mod c directly, exponents that would overflow a normal calculator are handled step-by-step in the remainder table.
Frequently Asked Questions
What does the Modulus Calculator do?
It computes modular arithmetic results including a^n mod c and remainders, useful for programming, cryptography, and number theory.
How do I use it?
Enter values for a, n and c to compute a^n mod c, or enter a dividend and divisor to find the remainder.
Is it free?
Yes. This Kod5 tool runs in the browser, requires no installation, and is free to use.
Mechanical Engineering Example: CNC Rotary Indexing
A rotary indexing fixture on a CNC machine has 12 equally spaced positions (0–11). The machining controller advances 5 positions per cycle. Which position does the fixture land on after the 4th cycle?
Calculate: 54 mod 12 = 625 mod 12 = 1 → the fixture is at position 1.
Set A = 5, n = 4, C = 12 in the calculator above to verify. This pattern is used in rotary indexing heads, bolt-hole drilling sequences, and cyclic gear engagement analysis.