What This Calculator Does
MRR (Monthly Recurring Revenue) and ARR (Annual Recurring Revenue) are the two headline metrics for any subscription business. MRR is the normalized monthly subscription revenue, excluding one-time fees and non-recurring charges. ARR is simply MRR multiplied by 12. This calculator builds your current MRR from the four components that move it every month: new business, expansion, contraction, and churn. It then computes ARR, net new MRR, growth rate, gross and net churn rates, and the SaaS quick ratio, so you can see not just where your recurring revenue stands but how it got there.
The headline MRR number alone hides the story. A company adding $50,000 in new business MRR while losing $30,000 to churn is growing, but the growth engine is leaking. A company adding $20,000 in new business and $40,000 in expansion while losing $5,000 to churn is growing faster and more efficiently, because expansion revenue costs far less to generate than new logo acquisition. The waterfall breakdown reveals which parts of the engine are working. According to Benchmarkit's 2026 report covering 342 B2B SaaS companies, expansion now supplies 40% of net-new ARR at the median, up from 30% in 2021.
To understand the churn side of the equation in detail, use our Churn Rate Calculator. For the full picture of how long each customer is worth, our Customer Lifetime Value Calculator ties MRR to long-term profit. And to see how long your cash supports the business while you grow recurring revenue, our Burn Rate Calculator shows runway.
Inputs Required
- New Business MRR: Recurring revenue from brand new customers acquired this month
- Expansion MRR: Additional recurring revenue from existing customers upgrading, adding seats, or moving to higher tiers
- Contraction MRR: Recurring revenue lost from existing customers downgrading or reducing seats (not cancellations)
- Churned MRR: Recurring revenue lost from customers who cancelled entirely
- Previous Month MRR: Total MRR at the start of the month, before any movements
Outputs Provided
- Current MRR: Previous MRR plus net new MRR
- ARR: Current MRR multiplied by 12
- Net New MRR: New plus expansion minus contraction minus churn
- MRR Growth Rate: Net new MRR divided by previous MRR, as a percentage
- Gross Churn Rate: Contraction plus churned MRR divided by starting MRR
- Net Churn Rate: Churned plus contraction minus expansion, divided by starting MRR
- SaaS Quick Ratio: New plus expansion MRR divided by contraction plus churned MRR
- MRR Waterfall: Step by step walk from starting MRR to ending MRR
How the Calculation Works
Net New MRR = New + Expansion - Contraction - Churned
Current MRR = Previous MRR + Net New MRR
ARR = Current MRR x 12
MRR Growth Rate = (Net New MRR / Previous MRR) x 100
Gross Churn Rate = ((Contraction + Churned) / Previous MRR) x 100
Net Churn Rate = ((Churned + Contraction - Expansion) / Previous MRR) x 100
SaaS Quick Ratio = (New + Expansion) / (Contraction + Churned)
MRR is normalized so that every customer is counted at their monthly recurring amount, regardless of billing frequency. An annual contract worth $12,000 per year counts as $1,000 in MRR. A quarterly contract worth $3,000 per quarter also counts as $1,000 in MRR. This normalization lets you compare months apples to apples and track growth cleanly. ARR is the annualized version, used for board reporting, fundraising, and benchmarking against the SaaS growth milestones that investors track.
The SaaS quick ratio measures the efficiency of growth. It compares the MRR you are adding (new plus expansion) to the MRR you are losing (contraction plus churn). A ratio of 4x means you are adding $4 for every $1 lost. Below 2x, growth is barely outpacing leakage. Above 4x is considered strong. The ratio is most useful for spotting when growth is being driven by acquisition masking high churn, or when expansion is doing the heavy lifting.
How to Use the Calculator
- Pull your subscription billing data for the month
- Enter new business MRR from customers who subscribed this month
- Enter expansion MRR from existing customers who upgraded or added seats
- Enter contraction MRR from existing customers who downgraded or reduced seats
- Enter churned MRR from customers who cancelled
- Enter your total MRR at the start of the month
- Review current MRR, ARR, the waterfall, and the churn and growth metrics
Example Calculations
Example 1: Early-Stage SaaS
A SaaS startup starts the month at $50,000 MRR. It adds $15,000 in new business, $3,000 in expansion, loses $2,000 to contraction, and $4,000 to churn. Net new MRR is $12,000. Current MRR is $62,000. ARR is $744,000. MRR growth rate is 24% for the month. Gross churn rate is 12%. Net churn rate is 6%. Quick ratio is 3x. The company is growing fast but churn is meaningful. At this stage, investors expect high growth and tolerate higher churn, but the quick ratio of 3x suggests growth is outpacing leakage comfortably.
Example 2: Mature SaaS
An established SaaS company starts the month at $1,000,000 MRR. It adds $25,000 in new business, $40,000 in expansion, loses $10,000 to contraction, and $15,000 to churn. Net new MRR is $40,000. Current MRR is $1,040,000. ARR is $12,480,000. MRR growth rate is 4% for the month, or roughly 48% annualized. Gross churn rate is 2.5%. Net churn rate is negative 1.5%, meaning expansion more than offset churn. Quick ratio is 4.6x. This is a healthy mature SaaS business with negative net churn, which is the gold standard. The SaaS Capital 2026 survey puts median NRR at 103% for private B2B SaaS, so this company is above the median.
Real World Scenarios
Spotting a Leaky Bucket
A SaaS company reports 8% month-over-month MRR growth, which looks strong. But the waterfall shows $30,000 in new business and $22,000 in churned MRR against a starting base of $200,000. Net new MRR is $8,000, a 4% growth rate, not 8%. The headline growth was inflated by counting new logos without netting churn. The quick ratio is 1.36x, well below the 4x threshold for strong growth. The company is spending heavily on acquisition to replace revenue leaking out the back door. The fix is retention work, not more ad spend. The calculator makes the leak visible in a way the headline MRR number does not.
Modeling ARR Milestones
A founder wants to project when the company will reach $10M ARR, a milestone investors track. Current MRR is $400,000 ($4.8M ARR). Monthly net new MRR is averaging $40,000, a 10% monthly growth rate. At that rate, MRR reaches $833,000 in 7 months, crossing $10M ARR. But growth rates decay as the base grows. ChartMogul's 2025 growth report shows the median startup takes just over 5 years to reach $10M ARR, with best-in-class companies reaching it in 2 years and 9 months. The founder uses the calculator to model different growth rate scenarios and set realistic milestones for the board.
Expansion Versus New Logo Strategy
A SaaS company at $2M ARR is deciding whether to invest in a sales team for new logos or a customer success team for expansion. It runs two scenarios. Scenario A: $30,000 new business, $10,000 expansion, $15,000 churn. Net new MRR is $25,000, quick ratio 2.7x. Scenario B: $15,000 new business, $35,000 expansion, $8,000 churn. Net new MRR is $42,000, quick ratio 6.25x. Scenario B produces more net new MRR at a lower acquisition cost, because expansion revenue from existing customers costs roughly a quarter of what new logo acquisition costs. The company invests in customer success first, then layers on sales once the expansion engine is proven.
Common Mistakes to Avoid
- Counting non-recurring revenue in MRR: Setup fees, professional services, and one-time purchases are not recurring. Including them inflates MRR and makes growth look stronger than it is. Only count subscription revenue that will recur next month
- Ignoring annual contract normalization: An annual contract billed at $12,000 per year counts as $1,000 MRR, not $12,000. Failing to normalize monthly makes MRR swing wildly based on billing frequency rather than actual growth
- Reporting gross churn without net churn: Gross churn shows how much you are losing. Net churn shows the net effect after expansion. A company with 5% gross churn but 8% expansion has negative net churn, which is excellent. Reporting only gross churn hides this
- Confusing MRR growth with ARR growth: A 10% MRR growth in one month is not 120% annual growth. Compounding changes the math. 10% monthly compounds to about 214% annually. Track both the monthly rate and the annualized trend to avoid overstating growth to investors
Limitations of This Calculator
This calculator computes MRR and ARR from a single month of movements. It does not handle multi-year contracts with ramp pricing, usage-based billing that fluctuates month to month, or deferred revenue recognition under ASC 606. It uses a simple starting MRR plus net new MRR approach, which works for most subscription businesses but may not match GAAP revenue recognition. The churn and growth rates are point-in-time monthly figures, not annualized or compounded. The SaaS quick ratio is most meaningful when tracked over multiple months, not as a single snapshot. For board reporting or audited financials, use dedicated subscription analytics tools like ChartMogul, Maxio, or Stripe Billing reports.
Authoritative Research & Resources
- Investopedia - Annual Recurring Revenue (ARR) - A reference defining ARR, how it relates to MRR, and why investors use it to value subscription businesses.
- ChartMogul - MRR Guide - ChartMogul, which tracks 2,500+ SaaS businesses, explains the four MRR components and how to use the waterfall for operational decisions.
- SaaS Capital - 2026 B2B SaaS Benchmarks - SaaS Capital's annual survey of over 1,000 private B2B SaaS companies, with median ARR growth, NRR, and GRR benchmarks by company size.