About
Stackyfull publishes payroll and contractor calculators for people running small businesses — owners, bookkeepers, office managers — who need one specific number and need it to be right.
Why this exists
Most calculators on the web are correct on the day they are published and never touched again. Rates change every January, and occasionally mid-year. Nothing on those pages tells you which year’s figures you are looking at, so a number that is quietly two years stale looks exactly like one that is current.
A concrete example, live as this is written: the IRS raised the business mileage rate from 72.5¢ to 76¢ effective 1 July 2026. Large, well-known calculators are still serving 72.5¢ as the 2026 rate. Anyone reimbursing recent travel from those figures is short by roughly 5%.
How these are maintained
Every calculator carries three things:
- A verification date — the day its underlying rates were last confirmed against a primary source, shown on the page rather than buried.
- Its sources — linked directly, and always the issuing authority (IRS, SSA, Department of Labor, state agencies) rather than an article about them. There are 15 across the 8 calculators.
- A review interval — how often that figure must be re-checked. Rates prone to mid-year change are reviewed far more often than stable ones.
An automated check runs against those intervals and fails when a calculator is overdue. When that happens the sources are re-read, the figures corrected, and the date updated. If a date on this site looks old, it is — we would rather show you that than hide it behind a vague “updated for 2026”.
How they are built
Each calculator runs entirely in your browser. Nothing you type is sent anywhere, there is no account, and no email is required. Where a figure is specific to your business — a state unemployment rate, a workers compensation rate — the calculator asks for it rather than assuming a national average, because assuming one produces a confident, wrong answer.
Where competing tools commonly get something wrong, the page says so explicitly and explains why. That is usually the most useful thing on it.
What this is not
These are estimates for planning, not tax or legal advice. See the terms and disclaimer. Corrections are genuinely welcome — if you believe a figure or a rule here is wrong, write to hello@metricmind.io and say which calculator and what it should be. Being told we are wrong is the fastest route to being right.