About Us

SumFrog builds fast, free online calculators and original data resources. Every tool shows its exact formula, a worked example, and the official sources behind any rates or reference values it uses.

We built SumFrog because too many calculator sites hide their math. Our rule: if we can't cite it, we don't publish it.

SumFrog is built and maintained by Leemingoo, an independent developer and data publisher. Every formula and tax figure on this site is verified against primary sources — IRS, SSA, and state revenue publications — before it goes live, and each page shows its sources and last-updated date.