Supplier cost change calculator

Your cost changed.
What happens to your margin?

Compare one item's old and new cost, then see the selling price needed for your target gross margin.

No sign-upNo file uploadCalculates in your browser

1. Enter your figures

Use the same currency, tax basis and unit for every amount. The starting figures are fictional.

Labels only; no currency conversion.
Greater than zero. Use a net selling price consistently.
0% to less than 100%. Margin is a share of selling price.
Same units and period before and after. This does not forecast sales.

2. Review the impact

Fictional example · selling price held unchanged

Current gross margin20%JPY 250.00 gross profit / unit
After cost change12%JPY 150.00 gross profit / unit

−8 percentage points of gross margin

Selling price for 20% gross marginJPY 1,375.00

A calculated price to review, not a prediction that customers will accept it.

Cost change per unit
+JPY 100.00 (+10%)
Markup on cost, before → after
25% → 13.64%
Gross profit change per unit
−JPY 100.00
Gross profit change at 2,000 units
−JPY 200,000.00

At the unchanged selling price and assumed quantity. This is a scenario, not a realised result or a sales forecast.

Margin and markup are different.

Gross margin divides gross profit by the selling price. Markup divides the same profit by cost. A 25% markup gives a 20% margin, not 25%.

Gross margin = (price − cost) ÷ price
Markup = (price − cost) ÷ cost

Gross profit here is revenue less the unit cost you enter. It does not include any overhead or other costs you have left out.

What price preserves the target?

Divide the proposed cost by the share of revenue left after your target margin. For a 20% margin, divide cost by 0.80.

Target price = new cost ÷ (1 − target margin)

JPY 1,100 ÷ 0.80 = JPY 1,375 in the fictional example. Review tax, fees, rounding and customer demand before changing a real price.

Limits and assumptions
  • No tax, exchange-rate or pack-size conversion. Align these yourself before comparing.
  • No live price updates, stock changes, accounting entries or connections to a shop or ERP.
  • Results are rounded for display; calculations use unrounded values. A displayed target price is not a rounded price recommendation.
  • Zero current cost has no defined percentage cost change or markup. Zero proposed cost cannot produce a target below 100% at a positive selling price.
  • Your inputs are not saved. Closing or reloading this page restores the fictional example.

Next step · compare a price list

More than one item to review?

FOCUS Margin Desk compares old and new supplier CSVs, flags mismatches and lets you review proposed prices before exporting. Try up to 25 rows per input table. Your business files stay on your computer.

Try Margin Desk free