In SQL, contribution margin for the whole period is ROUND(100.0 * (SUM(revenue) - SUM(cogs) - SUM(shipping_cost) - SUM(marketing_spend)) / SUM(revenue), 2) over the monthly table. On the sample data it returns 10.01.
Contribution margin = (Revenue − COGS − Shipping − Marketing) ÷ Revenue × 100
What you need
Contribution margin is the share of revenue left after the costs that grow with each sale: cost of goods, shipping and, for online brands, marketing. You need these columns, here from the sample file monthly.csv:
- revenue: revenue (net of discounts)
- cogs: cost of goods sold
- shipping_cost: shipping cost
- marketing_spend: marketing spend
CREATE TABLE monthly (
month TEXT, -- 'YYYY-MM'
revenue INTEGER,
cogs INTEGER,
shipping_cost INTEGER,
marketing_spend INTEGER
);Step by step
- Load monthly.csv into a table called monthly. The table only needs the month column and the columns below.
- Run the first query to get one row per month.
- Run the whole-period query. It adds up each column first and divides once; averaging the monthly results gives a different, usually wrong, answer.
The queries
SELECT
month,
ROUND(100.0 * (revenue - cogs - shipping_cost - marketing_spend) / NULLIF(revenue, 0), 2) AS contribution_margin
FROM monthly
ORDER BY month;SELECT ROUND(100.0 * (SUM(revenue) - SUM(cogs) - SUM(shipping_cost) - SUM(marketing_spend)) / NULLIF(SUM(revenue), 0), 2) AS contribution_margin
FROM monthly;What you should get
Run against the sample data, the code above returns these values (in percent):
| Month | revenue | cogs | shipping_cost | marketing_spend | contribution_margin |
|---|---|---|---|---|---|
| 2026-01 | 4,12,000 | 2,26,600 | 49,100 | 96,000 | 9.78% |
| 2026-02 | 4,38,500 | 2,36,800 | 52,400 | 1,02,000 | 10.79% |
| 2026-03 | 4,71,200 | 2,59,200 | 56,800 | 1,18,000 | 7.89% |
| 2026-04 | 4,55,800 | 2,55,200 | 54,000 | 99,000 | 10.44% |
| 2026-05 | 5,02,300 | 2,71,200 | 59,200 | 1,24,000 | 9.54% |
| 2026-06 | 5,48,900 | 2,90,900 | 64,200 | 1,31,000 | 11.44% |
| Whole period | 28,28,700 | 15,39,900 | 3,35,700 | 6,70,000 | 10.01% |
(₹28,28,700 − ₹15,39,900 − ₹3,35,700 − ₹6,70,000) ÷ ₹28,28,700 × 100 = 10.01%
Notes for SQL
- Integer columns divide as integers in PostgreSQL, SQLite and SQL Server, so 3 / 4 gives 0. Multiplying by 1.0 (or 100.0) first makes the division decimal.
- NULLIF(x, 0) turns a zero denominator into NULL, so the query returns NULL for that row instead of failing with a division-by-zero error.
- Tested on SQLite and DuckDB. SUM, NULLIF and ROUND work the same in PostgreSQL, MySQL and BigQuery; SQL Server uses TOP instead of LIMIT where a query has one.
Where contribution margin misleads
- Definitions vary. Some include payment fees and packaging, some exclude marketing (often called CM1, CM2, CM3). State which costs you subtract.
- Marketing spent this month brings customers who buy next month too, so monthly contribution margin swings with campaign timing.
- Returns and undelivered COD orders carry shipping both ways. Include return shipping if it is material.
The full explanation, with a calculator, is on the Contribution margin page.
Same metric, other tools
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About the data on this page
The figures come from a small made-up dataset, printed above in full so you can check every number by hand. Download it as monthly.csv. The results are computed from those rows when the page is built, and the Excel formulas, SQL and Python on these pages are run against the same rows before publishing, so the code and the answers agree.
To get these numbers from your own data without writing formulas, try AnalyzeIt: ask in plain words and it shows the working behind every figure.
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