Twin prime pair checker

Client

Twin primes like (11,13) sit two apart and both pass primality. Enter any pair to validate—great for conjecture demos.

How to use

Provide two integers. Both must be prime and |a−b| must equal 2.

About Twin prime pair checker

Test whether two integers form a twin prime pair (both prime, difference 2)—local trial division. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.

How to use this page

Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.

(11, 13) is a twin prime pair.

Nearby workflows on Toolcore

  • Prime number checker — Test whether a whole number is prime—BigInt trial division in your browser, no upload. when units or numeric output should be checked on a related calculator.
  • Prime factorization — Factor whole numbers into prime products—BigInt trial division in your browser, no upload. when units or numeric output should be checked on a related calculator.
  • Math expression evaluator — Evaluate basic + − × ÷ arithmetic with parentheses in your browser—no variables. when units or numeric output should be checked on a related calculator.
  • Collatz sequence — Generate the 3n+1 Collatz sequence from a starting integer until it reaches 1—local BigInt steps. when units or numeric output should be checked on a related calculator.

Common use cases

  • Check candidate pairs from sieve output.
  • Illustrate gaps in prime distributions.

Common mistakes to avoid

  • Pairs differing by 1

    Only (2,3) would be adjacent; twin primes require gap 2.

FAQ

Is (2,3) counted?

Gap is 1, so this tool reports they are not twin primes by the ±2 rule.

More tools

Related utilities you can open in another tab—mostly client-side.