Month Over Month Calculator
Measure month-over-month growth for revenue, users, traffic, or any metric. Enter last month's number and this month's number to get the MoM percent change, the raw change, and the annualized rate if you kept that pace for 12 months.
Example: with Last month's value 42000 · This month's value 48300 → Month-over-month change: 15.00% growth.
- Absolute change+6,300
- Annualized (compounded)+435.0% if sustained for 12 months
Computed by the calculator below using its default values. Change any input to see your own numbers.
MoM = (this month − last month) ÷ last month × 100. Annualized compounds that rate 12 times: (1 + MoM)¹² − 1.
What month-over-month growth tells you
Month-over-month (MoM) growth is the fastest feedback loop a business has: it compares this month directly to last month, so you see the effect of recent changes — a pricing test, a campaign, a product launch — without waiting a year. The formula is the plain percent change: subtract last month from this month, divide by last month, multiply by 100.
Small monthly rates compound into large annual ones. A steady 5% MoM is not 60% a year — it is 79.6%, because each month builds on the last. That is why startup investors quote MoM for young companies: at 15% MoM, revenue multiplies 5.35× in a year. The annualized line in this calculator does that compounding for you.
MoM is also noisy. February is short, December is seasonal, and one big invoice can swing a small company's number wildly. Read a single month as a data point, not a verdict — three or more months of direction is a trend.
How it’s calculated
MoM change = (current − prior) ÷ prior × 100. Absolute change = current − prior. Annualized rate = ((1 + MoM/100)¹² − 1) × 100, i.e., the monthly rate compounded for 12 months.
Assumes the prior month's value is positive; percent change from a zero or negative base is undefined. Annualization assumes the same rate repeats every month, which real metrics rarely do.
Monthly growth compounded for a year
| MoM rate | Annualized equivalent |
|---|---|
| 1% | 12.68% |
| 2% | 26.82% |
| 5% | 79.59% |
| 10% | 213.84% |
| 15% | 435.03% |
| 20% | 791.61% |
Computed with (1 + MoM)¹² − 1; rounded to two decimals.
Common mistakes
- Dividing by the new month instead of the old one — the base is always the earlier value.
- Annualizing by multiplying by 12; growth compounds, so 5% MoM is 79.6% a year, not 60%.
- Comparing a 28-day February against a 31-day March without normalizing to daily averages.
- Treating one strong month as a trend — seasonality and one-off deals swing small bases hard.
Frequently asked questions
What is the month-over-month formula?
MoM growth = (this month − last month) ÷ last month × 100. If revenue went from $42,000 to $48,300, that is 6,300 ÷ 42,000 = 15% growth.
How do I annualize a monthly growth rate?
Compound it: (1 + monthly rate)¹² − 1. A 15% MoM pace annualizes to 435%, not 180%, because each month grows on top of the previous month's larger base.
Can MoM growth be negative?
Yes. If this month is lower than last month the formula returns a negative percent — a 15% decline shows as −15%. The math is identical; only the sign changes.
Why is my MoM number so volatile?
Monthly figures carry seasonality, different month lengths, and one-off events. Many teams also track a 3-month average or year-over-year change to separate trend from noise.
MoM vs YoY — which should I use?
MoM shows momentum and reacts fast; year-over-year removes seasonality by comparing the same month last year. Fast-changing startups lean on MoM; seasonal businesses lean on YoY.