In Python, load the data with pandas and compute compound monthly growth rate from column totals for the whole period, or row by row for each month. On the sample data it returns 5.91.
CMGR = (Last month ÷ First month)^(1 ÷ Number of months between them) − 1
What you need
Compound monthly growth rate (CMGR) is the steady monthly growth rate that would take you from the first month's value to the last month's value. You need these columns, here from the sample file monthly.csv:
- df["revenue"]: revenue (net of discounts)
Step by step
- Install pandas (pip install pandas) and save monthly.csv next to your script.
- Run the script. The first print shows one row per month, the second the figure for the whole period.
- To use your own data, rename your columns to match, or change the names in the code.
The code
import pandas as pd
df = pd.read_csv("monthly.csv")
first, last = df["revenue"].iloc[0], df["revenue"].iloc[-1]
steps = len(df) - 1 # six months is five steps of growth
cmgr = ((last / first) ** (1 / steps) - 1) * 100
print(round(cmgr, 2))
What you should get
Run against the sample data, the code above returns these values (in percent):
| Month | revenue | cmgr |
|---|---|---|
| 2026-01 | 4,12,000 | — |
| 2026-02 | 4,38,500 | 6.43% |
| 2026-03 | 4,71,200 | 6.94% |
| 2026-04 | 4,55,800 | 3.43% |
| 2026-05 | 5,02,300 | 5.08% |
| 2026-06 | 5,48,900 | 5.91% |
| Whole period | 5.91% |
(₹5,48,900 ÷ ₹4,12,000)^(1 ÷ 5) − 1 = 5.91%
Notes for Python
- Dividing by zero in pandas does not raise an error: it gives inf or NaN. Check with df.replace([float("inf"), -float("inf")], float("nan")) before averaging or plotting.
- For the whole period, sum the columns first and then divide. df[col].mean() of the monthly results weights a small month the same as a large one.
- pct_change(), groupby() and resample() extend the same idea to weekly data, product categories and daily rows.
Where compound monthly growth rate misleads
- Only the first and last values matter. A great first month or a weak last month changes the answer a lot.
- Use full months at both ends; a partial month at the end makes growth look worse.
- To compare with a yearly figure, (1 + CMGR)^12 − 1 gives the annualised rate.
The full explanation, with a calculator, is on the Compound monthly growth rate (CMGR) 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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