About Percentage Calculator

Supported calculations

The app calculates percent of a number, what percent one value is of another, percentage increases/decreases, directional percentage change, and symmetric percentage difference.

Calculation method

The engine parses ordinary decimal input into exact BigInt rational values instead of using binary floating-point accumulation as calculation truth. Repeating or longer results can be rounded for display and are marked approximate.

Important boundaries

Percentage change uses Original as the baseline and requires Original greater than zero in this version. Percentage difference uses the average-denominator convention and is undefined when both inputs are zero. The app does not provide financial, tax, health, academic, legal, or other professional advice.

Local-first behavior

Entered values and mode drafts live in page memory. The app does not create an account, cloud history, or recovery service. Share App shares the canonical app URL rather than entered values or results.

Privacy, data and limits

Percentage Calculator processes entered values and mode drafts only in the current browser page. It does not upload calculator work or maintain an app-owned calculation history, account, cloud copy, or recovery service.

Results use deterministic decimal/rational arithmetic. Repeating or very long values can be rounded and marked approximate. Percentage change uses Original as the baseline and requires Original greater than zero in this version; percentage difference uses the average-denominator convention and is undefined when both inputs are zero. The app provides general mathematical calculations, not financial, tax, health, academic, legal, or other professional advice. Share App shares only the canonical app URL, not entered values or results.

For platform-wide practices, read the Mycelgrid Privacy Policy and Terms of Use. For a real product problem or accessibility issue, use Contact Mycelgrid.