How to Calculate MRR Growth: SaaS Formula

The Basic MRR Growth Formula

The simplest way to measure MRR growth is the month-over-month rate: MRR Growth Rate = (Ending MRR − Starting MRR) / Starting MRR. If you start January at $40,000 MRR and end at $44,000, your growth rate is 10%. But this single number hides the machinery underneath, so serious SaaS operators break growth into its moving parts.

Net New MRR is the absolute dollar change: Net New MRR = New MRR + Expansion MRR − Contraction MRR − Churned MRR. Tracking net new MRR in dollars alongside the percentage rate matters because a 20% rate on a $10k base ($2k added) is a very different business signal than 20% on a $1M base ($200k added). Our MRR Growth Projector models both simultaneously.

Worked Example: Breaking Down a Month

Consider a SaaS that starts the month at $100,000 MRR:

• New MRR: $18,000 from 36 new customers
• Expansion MRR: $6,000 from upgrades and seat additions
• Contraction MRR: −$2,500 from downgrades
• Churned MRR: −$7,500 from cancelled accounts
• Net New MRR: $18,000 + $6,000 − $2,500 − $7,500 = $14,000
• Ending MRR: $114,000
• Growth rate: $14,000 / $100,000 = 14%

This breakdown tells a richer story than "14% growth": the company added $24,000 of gross new revenue but lost $10,000 — meaning churn is eating nearly 42% of growth. That insight points straight at retention work, which our Churn Rate Calculator can help quantify.

CMGR: Smoothing Growth Over Time

Month-to-month growth bounces around, so founders use the Compound Monthly Growth Rate (CMGR) to measure the smoothed trend: CMGR = (Ending MRR / Starting MRR)^(1 / months) − 1. If MRR grows from $50,000 to $150,000 over 12 months, CMGR is ($150k/$50k)^(1/12) − 1 ≈ 9.6% per month.

CMGR is the number investors quote in pitch decks ("we've grown at 10% CMGR for the past year") because it is honest about compounding. A useful rule of thumb: 10% monthly growth doubles revenue roughly every 7.3 months (the Rule of 72 applied monthly). For longer-range modeling, see our guide to MRR Forecasting Methods.

Growth Efficiency: How Hard Are You Working for It?

Raw growth does not show what it cost. Two metrics add that context:

• Quick Ratio: (New MRR + Expansion MRR) / (Contraction MRR + Churned MRR). Above 4 is generally considered strong; below 2 suggests growth is being washed out by churn.
• Burn multiple: Net burn / Net new ARR. It answers "how many dollars did we burn to add one dollar of ARR?" Lower is better; healthy efficient growers often run under 2.

Pairing growth with efficiency keeps you honest: 15% monthly growth funded by unsustainable spending is not a strategy, it is a countdown. For the retention side of the equation, read our SaaS Churn Benchmarks.

Working Backwards From Your ARR Target

Growth math is most useful in reverse: start with the goal and derive what each month must deliver. Suppose you are at $400,000 ARR ($33,333 MRR) and target $1M ARR in 12 months. You need $600,000 of net new ARR — $50,000 of net new MRR per month on average. But churn takes its cut first: if monthly revenue churn runs 3% on a growing base averaging ~$55,000 MRR, you lose roughly $1,650/month to churn, meaning gross additions must average about $51,650/month.

This reverse math exposes whether a target is realistic. Needing $52,000/month of gross new MRR with a $2,000 average contract means 26 net new customers monthly after accounting for expansion — do you have the pipeline and sales capacity for that? If the required customer count exceeds your historical best by 5x, the target (or the plan) needs revising before the year starts, not in month nine.

• Set the ARR goal and convert to required monthly net new MRR.
• Add back expected churn to get required gross additions.
• Convert to customers using realistic average contract values.
• Sanity-check against capacity: pipeline, sales headcount, and historical conversion.

Run these scenarios interactively in our MRR Growth Projector, then formalize the plan with our MRR Forecasting Methods guide.

Conclusion

Calculate MRR growth as both a percentage and an absolute dollar figure, decompose it into new, expansion, contraction, and churned MRR, and smooth it with CMGR before quoting it anywhere important. Growth you can decompose is growth you can manage — and growth you can defend in front of investors. Start modeling with the MRR Growth Projector and validate your pricing with SaaS Pricing analysis.