Mathlean · Online math workspace
Prime-counting function calculator
Count primes no greater than an input bound.
How to use this calculator
Replace 100 in PrimePi; there are 25 primes at most 100.
Tap the math below to edit it and see the result. Once a result is ready, press Tab on a hardware keyboard to accept it. Outside a matrix, Return completes the line; the phone math keyboard has the same Return action.
Try it here
Interactive tools require JavaScript. You can read the guide and example without it.
What to know
Prime-counting is different from requesting the nth prime. Large bounds may exceed the computation budget.
Mathlean combines visual mathematical input with computation and canvas tools. Results depend on the expression and available engine support; check important answers independently.