CAGR is the cleanest way to compare growth across companies, products, or time periods of different lengths. Instead of saying "we grew 280% over four years," CAGR translates that into "we grew at 39% per year compounded" — which is directly comparable to any other annual growth rate, anywhere.
The intuition
If your subscription MRR was $100,000 at the start of year 1 and $250,000 at the end of year 4, you grew 150% over four years. But that's not 37.5% per year (150% ÷ 4) — because growth compounds. The actual annual rate that, if applied consistently, would turn $100K into $250K in four years is about 25.7%. That's the CAGR.
When to use CAGR
- Comparing multi-year growth across products, business lines, or competitors.
- Reporting investor-facing growth in fundraising decks and annual reports.
- Forecasting steady-state growth when you have a long enough history to smooth seasonal noise.
- Benchmarking against market growth (e.g., the subscription ecommerce market grew at 16% CAGR from 2018 to 2024 — how did you compare?).
When NOT to use CAGR
- Volatile periods. CAGR smooths everything into a single rate. If 90% of your growth came in one year, CAGR hides that.
- Very short periods. A 6-month CAGR is mostly noise. Use month-over-month or quarter-over-quarter growth instead.
- Forecasting future growth. Past CAGR is a description, not a prediction. Many businesses' growth rates decline sharply as they scale.
- Negative starting values. The math breaks. Use absolute change or a different metric instead.
For subscription merchants
CAGR is most useful when reporting MRR or ARR growth across three years or more. Below that, month-over-month and year-over-year growth rates tell the operating story better. Above that, CAGR becomes the natural lens — and the metric investors will ask for first.
See compound annual growth rate formula for the calculation walkthrough and growth rate for the broader concept.