Calculator
Free maximum purchase / bid calculator
Enter the expected resale proceeds, every cost you expect to pay after purchase, and the minimum profit you want. The result is the maximum purchase price before the deal falls below that target.
Maximum purchase price£260.00
Target profit£40.00
Headroom vs resale86.7%
Why work backwards from resale?
Starting from the current bid and asking whether you can “go a little higher” encourages auction drift. Starting from a defensible resale estimate, costs and target profit gives you a fixed ceiling.
Do not use a full-product resale value for an incomplete listing
Scope matters. Box-only, accessory-only, parts and missing-core-item listings need their own resale evidence before you calculate a ceiling.
Lower the ceiling when evidence is weak
This calculator is pure arithmetic. It does not judge market confidence. If the expected resale value is uncertain, use a more conservative resale input or increase the profit/headroom you require.