Proofwell is a collection of free calculators for mathematics, chemistry, physics and biology. It is built for students checking homework, teachers preparing examples and anyone who wants to understand how an answer was reached, not just what it is.
What makes these calculators different
- They show their working. Each result comes with the steps that produced it.
- They explain the method. Every calculator page includes the formula, a worked example and common mistakes.
- They are verified. Each calculator is tested against published reference values before it goes live. Read how we verify results.
- They are free and private. No sign-up is needed, and calculations run in your browser.
Using the results
These tools are designed for learning and for checking your own work. For decisions where an error would have serious consequences, such as clinical, engineering or safety-critical work, verify results independently with a qualified professional.