Net profit is the final "what's left" figure after the business pays for everything it consumed to generate revenue. For subscription merchants the formula is identical to net income; the words are used interchangeably in most contexts. Where the distinction matters, "net profit" tends to be the operational language and "net income" the accounting term.
The formula in full
Net Profit = Revenue − COGS − Operating Expenses − Interest − Taxes
Or, equivalently:
Net Profit = Operating Profit − Interest − Taxes
Both arrive at the same number. The expanded form is more useful for diagnosis (which line is eating your margin?); the compact form is more useful for forecasting (what is your effective tax + interest drag?).
Operational use for subscription merchants
Net profit is what you actually take home. For a subscription business, two characteristics make net profit especially diagnostic:
- It is sensitive to churn. Acquired customers who churn before payback drag net profit into negative territory.
- It lags revenue. Strong subscription growth often shows positive top-line and negative net profit because acquisition spend front-loads while revenue accrues over months.
This is why subscription businesses are often valued on revenue and retention metrics rather than current net profit — investors are pricing the path to profitability, not today's number.
How to actually use the formula
Run net profit monthly, but read it as a 3-month moving average. Subscription monthly numbers swing too much on inventory timing, marketing pulses, and refund cycles. The 3-month view shows the underlying trajectory. Pair it with net profit margin — the percentage view — for comparability across periods of different revenue size.