Tools that teach
A calculator you understand beats one you just trust.
SumLoft builds clean, fast financial calculators for saving, investing, and loans, each paired with a plain-English guide.
SumLoft calculators and explainers are written by our editorial team, turning intimidating math into steps a reader can follow and check by hand. Figures are illustrative and labelled, and articles are edited by Hamza Hai, MBA. They are educational general information, not financial advice.
Hamza Hai, MBA
Editor, SumLoft
Hamza Hai is the editor of SumLoft. She holds an MBA and reviews the site's articles against our editorial standards, checking that every figure is labelled for what it is, that nothing is presented as verified fact without a source the reader can check, and that the writing stays useful to a non-specialist.
How we build
Every calculator is paired with a guide that explains the formula and the assumptions, so the answer is legible, not magic.
How we make money
At the time of writing this site carries no affiliate links and no advertising. No link earns a commission and no company pays for coverage. If that ever changes, the disclosure page will say so first and any paid link will be marked where it appears.
How we research each walkthrough
Every walkthrough follows the same path from the raw formula to a number you can trust.
- Start from the standard formulaEach walkthrough is built on the same amortization and compound-growth math our calculators run, not a rule of thumb.
- State the assumptions plainlyRates, timelines, and inputs are written out so you can see exactly what drives the result.
- Explain the lever, not just the answerEvery calculator is paired with a guide that explains the formula and the assumptions, so the answer is legible, not magic.
- Label estimates as illustrativeOutputs are estimates for education, not quotes or financial advice, and we say so on every result.