Practical guides
Useful explanations, examples, and checks for common everyday tasks.
Format and check JSON safely
Learn how formatting exposes structural mistakes while keeping sensitive samples in your browser.
Read guide →Compound-interest assumptions explained
Understand compounding frequency, nominal rates, and the limits of a simple projection.
Read guide →How to calculate percentages with confidence
Use three common percentage patterns, check the result, and avoid decimal-place mistakes.
Read guide →