Net Profit Calculator — Methodology

Step-by-step calculation

Walk down the income statement from revenue to net profit after COGS, operating expenses, interest, and tax.

1. 1

   Enter total revenue

   Top-line revenue for the period — typically annual.

2. 2

   Add COGS and operating expenses

   Cost of goods sold first; then operating expenses like rent, salaries, marketing.

3. 3

   Add interest expense

   Total interest paid on any business loans or credit lines in the period.

4. 4

   Confirm the tax rate

   Pre-filled by region. Override if you have a different effective rate.

5. 5

   Read the full waterfall

   Gross profit → operating profit (EBIT) → EBT → net profit, with net margin as a percentage.

Assumptions and overrides

Tax rate pre-fills at headline corporate rates (US 21%, UK 25%, SA 27%). Override for: US state tax additions, UK small profits rate (19% under £50k), SA turnover tax (small business alternative).

Every region default on the calculator is editable. If your effective rate, fee, or threshold differs from the headline figure shown, type your own number into the field — the calculator recomputes instantly without leaving this page.

Primary sources

Region-tagged primary sources for the default rates, thresholds, and benchmarks used in this calculator.

• USAIRS — Form 1120 (US corporate tax 21%)
• UKGOV.UK — UK Corporation Tax rates (25% / 19% small profits)
• SASARS — Corporate Income Tax (27% standard)

Review cadence and corrections

This methodology and the underlying rate defaults are reviewed at least annually, and immediately following any change to the headline rate from IRS, HMRC, or SARS. Every substantive update is recorded on the public changelog. Spotted an error? See the corrections policy for how to report it.

See the full editorial policy for the standards every page on BusCalcTools is held to.