In SQL, inventory turnover for the whole period is ROUND(1.0 * SUM(cogs) / SUM(inventory_value), 2) over the monthly table. On the sample data it returns 0.39.
Inventory turnover = Cost of goods sold ÷ Average inventory value (at cost)
What you need
Inventory turnover is how many times you sell through your average stock in a period: cost of goods sold divided by average inventory valued at cost. You need these columns, here from the sample file monthly.csv:
- cogs: cost of goods sold
- inventory_value: average inventory value (at cost)
CREATE TABLE monthly (
month TEXT, -- 'YYYY-MM'
cogs INTEGER,
inventory_value 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(1.0 * cogs / NULLIF(inventory_value, 0), 2) AS inventory_turnover
FROM monthly
ORDER BY month;SELECT ROUND(1.0 * SUM(cogs) / NULLIF(SUM(inventory_value), 0), 2) AS inventory_turnover
FROM monthly;What you should get
Run against the sample data, the code above returns these values:
| Month | cogs | inventory_value | inventory_turnover |
|---|---|---|---|
| 2026-01 | 2,26,600 | 6,10,000 | 0.37 |
| 2026-02 | 2,36,800 | 6,40,000 | 0.37 |
| 2026-03 | 2,59,200 | 6,55,000 | 0.40 |
| 2026-04 | 2,55,200 | 6,90,000 | 0.37 |
| 2026-05 | 2,71,200 | 6,72,000 | 0.40 |
| 2026-06 | 2,90,900 | 7,05,000 | 0.41 |
| Whole period | 15,39,900 | 39,72,000 | 0.39 |
₹15,39,900 ÷ ₹39,72,000 = 0.39
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 inventory turnover misleads
- Value inventory at cost, the same basis as COGS. Using retail value makes turnover look slower.
- Average inventory should be an average over the period, not the closing figure, or one big delivery distorts it.
- Very high turnover can mean you are running out of stock and losing sales. Check stock-outs too.
The full explanation, with a calculator, is on the Inventory turnover 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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