How to Calculate Rate of Growth Without Lying to Your Board
Three formulas cover 95% of the cases. The other 5% is where founders accidentally fabricate hockey sticks. We walk through both.
The Basic Growth Rate Formula
When someone asks how to calculate rate of growth, they usually mean this: how much bigger is a number today versus a number from before? The formula is almost embarrassingly simple.
Growth Rate = ((Ending Value − Starting Value) / Starting Value) × 100
Example: Shopify’s revenue went from $5.6B in 2022 to $8.88B in 2024. (8.88 − 5.6) / 5.6 × 100 = 58.6% growth over that two-year window. Clean number, honest story.
That formula works for revenue, users, email subscribers, MRR, ARR, active installs, or any other count. The inputs change. The math stays the same.
Month-Over-Month vs. Year-Over-Year
This is where most founders mess up. The formula is identical, but which window you pick decides whether your chart looks exciting or flat.
- MoM: compare this month to last month. Noisy, but fast signal.
- YoY: compare this month to the same month a year ago. Smooths out seasonality.
- Trailing 3-month average: our favorite for SaaS MRR. Kills the end-of-quarter spikes.
A client of ours was reporting 34% MoM growth in December 2025. Beautiful. Then January came in at −18%. Turned out they had pulled Q1 renewals forward. If they had been reporting YoY from the start, the board would have seen a steady 22% trend instead of whiplash.
Our rule of thumb: if your product has any seasonality (and almost every B2B product does), default to YoY for headline numbers and keep MoM as a diagnostic. Investors know this. Board members usually do too. Reporting MoM as your hero metric signals that you are hiding something or new to the role.
CAGR: When You Span Multiple Years
Compound annual growth rate is how to calculate rate of growth when the window covers more than 12 months. It tells you the constant annual rate that would get you from A to B over N years.
CAGR = ((Ending Value / Starting Value) ^ (1/N)) − 1
Using the Shopify numbers: (8.88 / 5.6) ^ (1/2) − 1 = 0.26 or 26% CAGR. Notice how 58.6% total growth translates to a calmer 26% annual figure. That is the number you want for a five-year forecast.
CAGR gets abused more than any other growth metric. Analysts use it to make lumpy businesses look smooth. The CAGR between 2020 and 2024 might be 31%, but if all of that growth happened in 2021 and the company has been flat for three years, the 31% CAGR tells an expensive lie. Always show the raw annual numbers next to the CAGR so the reader can spot the shape.
The Four Traps That Ruin Growth Numbers
We have audited over 60 pitch decks in the last two years. The same mistakes show up.
- Cherry-picked start date: measuring from the company’s worst month makes any recovery look like a rocket
- Mixing units: sign-ups, activated users, and paying customers are three different curves
- Ignoring churn: gross MRR growth minus churn is what actually matters
- Small-base illusion: going from 4 customers to 8 is 100%, but it is still 8 customers
A Series A founder we worked with learned this the hard way when an investor ran the numbers with churn included and the 340% “growth rate” dropped to 44% net. The term sheet disappeared the next week.
The honest version of every growth number has three parts: the metric, the window, and the base. “We grew 40% YoY in paying customers from a base of 420” is a sentence an investor can trust. “We grew 40%” is a sentence that makes them open a second spreadsheet.
A Quick Calculator for Marketing Teams
If you run paid acquisition at WebCoreLab or anywhere else, you want these four numbers on one line in your weekly report:
- Revenue growth YoY (main headline)
- New customer growth MoM (leading indicator)
- Pipeline CAGR over trailing 12 months (smooths seasonality)
- Net revenue retention (the honesty check)
If all four move in the same direction, your marketing is actually working. If only the first one moves, you are probably pulling forward demand.
The Spreadsheet We Hand Clients
When a client asks us how to calculate rate of growth for their specific setup, we usually send a three-tab Google Sheet. Tab one: raw monthly numbers. Tab two: auto-calculated MoM, YoY, trailing 3-month, and rolling CAGR. Tab three: a chart that a non-finance exec can read in 10 seconds.
Boring, but it has closed more funding conversations than any pitch template we have seen.
If you want a fast way to sanity-check any growth claim you see in a pitch deck or press release, ask three questions. What was the base? What was the window? And what happens if we strip out one-time events like acquisitions or price hikes? Most “triple-digit growth” claims fall apart inside 90 seconds of that check. The ones that survive are worth the premium on the term sheet.
