Chinese Remainder Calculator

Signed decimal integer, at most 200 digits; no decimal point or exponent notation.
Signed decimal integer, at most 200 digits; no decimal point or exponent notation.
Signed decimal integer, at most 200 digits; no decimal point or exponent notation.
Signed decimal integer, at most 200 digits; no decimal point or exponent notation.
Math

Chinese Remainder with stated conventions, validation and a worked example.

Formula

Solve x≡a (mod m), x≡b (mod n); consistency requires gcd(m,n) to divide b−a.

Example Calculation

Example inputs
  • Residue a: 2
  • Modulus m: 3
  • Residue b: 3
  • Modulus n: 5

x≡2 mod3 and x≡3 mod5 give x=8+15k, for any integer k.

Frequently asked questions

How do I use this calculator?

Enter residue a, modulus m, residue b, modulus n. The result updates automatically. Use Reset to restore the example values.

What method does it use?

Solve x≡a (mod m), x≡b (mod n); consistency requires gcd(m,n) to divide b−a.. Exact integer arithmetic uses BigInt. Enter signed decimal integers of at most 200 digits unless a different limit is stated. Decimal approximations are explicitly labelled. Non-coprime moduli are supported when the congruences are compatible.

Why might a rounded result differ?

The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.

Are my inputs saved online?

No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.

Check the assumptions and units before using this result. Read about calculation methods.