Ask “what would change?”
Calculate a model, compare assumptions and find a candidate input for a target result.
A fictional one-period project. Price minus variable cost is contribution per unit; fixed cost is deducted once. Fractional units are allowed during numeric search.
Start with the model
Enter rates as decimals (0.06 means 6%). Changing inputs or formulas clears previous results. All calculations stay in this browser.
Use the right question
- Calculate first: read the baseline, units and signs before changing an assumption.
- Work backward: use one changing input and a target result. Review the residual and bounds before applying a candidate.
- Compare forward: use a sensitivity table for one or two independent inputs, or name a set of assumptions together.
- Check the model: a mathematically reached target can still depend on unrealistic inputs. These fictional models have no fees, taxes or uncertainty.
Local model formulas must return finite scalar numbers. No connected sources, volatile functions, external worksheets or dynamic addresses are evaluated. Native Excel search/recalculation parity is not certified.