What this site does
Three browser calculators cover proposed scope changes, markup versus margin and cost to complete. Each exposes the formula, input boundaries and a worked example. Examples are fictional and do not represent customer results.
Who built it
This is an independent software project by a software engineering student. It was built with AI-assisted development, code review and automated calculation tests. The site does not claim contractor, accounting or financial-advisory credentials.
Calculation methodology
Money is read as integer cents. User percentages are read as basis points. Price floors round upward to the next cent; displayed percentages round separately. We accept at most two decimal places, reject non-finite and out-of-range inputs, and clear an old result as soon as inputs change. The currency selector relabels the amounts; it performs no foreign-exchange conversion.
Impact inputs are limited to an absolute value of 10,000,000.00 each. Target margin must stay below 100%. Markup supports 0–1,000%. A zero denominator gives an undefined ratio rather than a misleading zero percent.
What remains your judgement
The tools do not know whether a scope is complete, a commitment is cancelled, tax is recoverable or an estimate is realistic. They cannot recommend an appropriate target margin. Compare results with your records before making an agreement.
Corrections and advertising
Report a calculation problem with synthetic numbers through the contact page. These free tools use Google AdSense. Google determines whether ads are shown and where they appear. Any ads shown are separate from calculator results. See the privacy notice for details.