Translate a supplier letter into a till decision
A 10% cost increase does not mean the selling price must rise by 10%. VAT and the existing product margin change the relationship. This calculator compares the old and new GP on the same selling price, then finds the price required for your chosen target.
What the result cannot predict
The model holds volume, mix and waste constant. It does not estimate customer response, competitor pricing or whether the item helps sell other profitable products.
This is the bridge to the paid product. A margin book would update one supplier cost and show every affected pint, serve, cocktail or dish that has dropped below target.