About WrenchMath
Brian Maldonado is a software engineer. He built WrenchMath because the calculators he found online for small-engine and powersport work were almost universally unsourced and untested: pages that display a number with no explanation of where the formula came from, no indication that anyone had verified it, and no update history. That is not a good foundation for work where a lean jetting error can destroy an engine or a wrong premix ratio can damage a two-stroke in a single tank.
How the formulas are verified
Every calculator on this site starts with a primary source. For engine and drivetrain formulas that means manufacturer operator's manuals or published service references. For physics-based calculations (air density, atmospheric correction factors, the gas laws) it means peer-reviewed references and established meteorological standards (NWS, WMO). A formula is not added until there is a citable, traceable source for it. The formula is then implemented in Go, the same language used for the build system, and the build system runs a parity check: every formula is implemented twice, once in the page logic and once in a separate verification package, and a machine check proves they agree to within one part per billion (1e-9) before any page ships. Pages carry a last-reviewed date so you know how recently the content was checked; "last reviewed" means the source was re-read and the parity check re-run on that date, not just that the page was touched.
Sources and corrections
Source citations appear on every calculator page. If you see a formula without a citation, that is a bug; please report it. If you believe a formula produces a wrong result, include the inputs you used and the result you expected; that makes the error reproducible. Confirmed corrections are applied promptly and the page's last-reviewed date is updated. Every report is read.