Financial calculators that show their formula
Free calculators for saving, interest, budgeting, investing and credit – with a transparent calculation path, tested examples and clearly stated limits. No product recommendations, no account, no data collection.
- Open formula: every calculator explains how it computes – with variables and examples.
- In your browser: your inputs are neither stored nor transmitted.
- Neutral: no product recommendations, no “current rates”, no advice.
- Tested: every calculation function passes automated tests with edge cases.
Calculators
The portal is launching step by step. Each calculator is tested and reviewed before it appears here – nothing is published until it passes. See the calculator overview or read how we work on the methodology page.
Why you can trust the results
Every calculator is based on an independently tested calculation function: at least five automated tests, edge-case tests and control calculations against independently derived reference values. Assumptions and limits are shown visibly on every calculator page – and where numbers are examples, they are explicitly marked as an example assumption. Your inputs stay in your browser, without an account and without tracking.