Calculate Prime Numbers
Quickly create a sequence of prime numbers. Runs entirely in your browser, so your data never leaves your device.
Output
The result appears here as you type.
How to use Calculate Prime Numbers
- 1. Set how many primes to generate. Enter the How many primes value to decide the length of the list. Nothing needs to be pasted, since the primes are generated using a sieve of Eratosthenes.
- 2. Set a starting point and separator. Use Start from to begin the list at a specific number instead of 2, and choose the Separator that joins the resulting values.
- 3. Copy the prime list. Copy the resulting sequence of prime numbers from the output for your math assignment, cryptography exploration or programming reference.
When to use Calculate Prime Numbers
Calculate Prime Numbers generates a sequence of primes starting from any point you choose, computed with a sieve of Eratosthenes rather than trial division. It is for anyone who needs a verified list of primes without writing a sieve themselves.
- Testing a primality-checking algorithm. A developer implementing their own prime sieve or primality test for a coding assignment wants a trusted reference list to compare their program's output against.
- Finding primes within a specific range. You need all primes starting from a number like 1000 for a number theory exercise and want to skip the small primes you already know.
- Building a math class handout on primes. A teacher preparing a lesson on prime numbers wants a clean, correctly generated list to print for a worksheet or classroom activity.
- Exploring prime gaps. You are studying the gaps between consecutive primes and want a longer list than is convenient to compute by hand to look for patterns.
Examples
The first ten primes
Output
2, 3, 5, 7, 11, 13, 17, 19, 23, 29
About the Calculate Prime Numbers tool
Calculate Prime Numbers does its work locally, right in the browser. Quickly create a sequence of prime numbers. There is no upload step, no queue and no account, and your data never travels over the network.
It belongs to the Number Tools collection on EditSafely, a set of 194 small, focused Number utilities that share the same instant, private workspace.
You can shape the output with 3 settings, including How many primes, Start from and Separator, and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
Running locally also makes the tool fast and dependable: results appear as you type or drop a file, there is no server outage that can take it down mid-task, and confidential data can be processed without a second thought.
Frequently asked questions
Does Calculate Prime Numbers cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Does the generator send anything to a server?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How do I get a different result?
Run the generator again. Each run is computed fresh on your device, and any options you change are applied to the next result immediately.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.