The basic calculation
If only revenue matters, the break-even customer loss is 1 − old price ÷ new price. Raising a price from $10 to $12 gives 1 − 10 ÷ 12, or about 16.7%. Revenue would be unchanged if fewer than 16.7% of customers left and all other factors stayed equal.
Include variable costs
Revenue is not profit. When serving each customer has a variable cost, compare contribution margin instead: price minus the variable cost. A price change can improve gross profit even when revenue is flat, or do the opposite if costs also change.
What this estimate leaves out
Customers may downgrade, buy less often, or return later. Competitors may react. Fixed costs, taxes, discounts, and customer-acquisition costs can also change the result. Treat the formula as a scenario to test, not a prediction.
Try your numbers
The Price Increase calculator compares revenue and contribution margin using the assumptions you enter. Check several churn rates before making a decision.