Monthly recurring revenue is the recurring subscription revenue expected in a month — the sum of every active customer's monthly plan value. MRR is the SaaS growth metric because it isolates the predictable recurring base from one-time fees. The calculator builds MRR from your customers and average revenue per customer, then projects the annual figure.

CAC payback estimates the months needed for gross-margin revenue from a customer to cover the cost of acquiring them: CAC divided by (ARPU x gross margin). A $300 CAC with $40 monthly gross profit pays back in 7.5 months. Healthy SaaS benchmarks typically fall between 5 and 12 months of payback.

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SaaS MRR Calculator | Project ARR, LTV, Churn, and CAC Payback

Model the core SaaS unit economics — MRR, ARR, LTV, churn impact, and CAC payback — from customers, pricing, and retention inputs. See how churn erodes growth and what payback your acquisition spend really needs, using the standard simplified formulas.

Last updated: August 2026 · Free · No sign-up required

Project SaaS MRR, ARR, monthly change, estimated LTV, and CAC payback from editable unit-economics assumptions.

How this tool works

MRR is customers multiplied by average revenue per customer. LTV uses ARPU, gross margin, and monthly churn; CAC payback compares acquisition cost with gross-margin revenue per customer.

Worked example

Enter representative inputs, review the result, and adjust assumptions to compare scenarios.

Frequently asked questions

What is MRR?

Monthly recurring revenue is the recurring subscription revenue expected in a month, excluding one-time charges.

How is ARR estimated?

This calculator annualizes current MRR by multiplying it by twelve.

What does churn do to MRR?

Monthly churn reduces the recurring revenue base by the selected percentage before new and expansion revenue are added.

How is SaaS LTV estimated?

The simplified estimate uses ARPU multiplied by gross margin and divided by monthly churn.

What is CAC payback?

CAC payback estimates the months needed for gross-margin revenue from a customer to recover acquisition cost.

Why are these SaaS metrics estimates?

Definitions, cohorts, contracts, annual prepayment, expansion, downgrades, and accounting treatment vary by business.

Quick reference

Metric	Formula	Healthy Benchmark
MRR	Customers × ARPA	Growing monthly
ARR	MRR × 12	—
LTV	ARPA ÷ monthly churn	≥ 3× CAC
CAC payback	CAC ÷ (ARPA × margin)	< 12 months
Net revenue retention	Revenue now ÷ same cohort a year ago	> 100%

domain Core metrics

MRR, ARR, LTV, CAC payback.

monitoring Churn impact

See what churn really costs.

lightbulb Pro tip

Watch CAC payback, not just LTV:CAC.

lightbulb Worked example

200 customers at $50/mo, 2% monthly churn, 80% gross margin, $300 CAC.

Result: MRR $10,000, ARR $120,000, LTV $2,000, payback 7.5 months.

Formula & methodology

Formula: MRR = Active Customers × Average Revenue per Account. ARR = MRR × 12. LTV = ARPA ÷ Monthly Churn Rate. CAC Payback = CAC ÷ (ARPA × Gross Margin).

How the SaaS unit economics are modeled

The tool builds MRR from customers × ARPU, annualizes it to ARR, then applies the standard simplified formulas: LTV = ARPU × gross margin ÷ monthly churn, and CAC payback = CAC ÷ (ARPU × gross margin). Churn is modeled as a monthly decay on the revenue base.

Example: 200 customers at $50/mo with 2% monthly churn and 80% margin give MRR $10,000, LTV $2,000, and a $300 CAC paying back in 7.5 months.

Reading the result: the LTV/CAC ratio — LTV divided by CAC — should exceed 3 for a healthy business model. These are simplified cohort-level formulas; real SaaS metrics vary with expansion revenue and contract terms, so use them for benchmarking and planning rather than exact reporting.

Authoritative source: https://www.investopedia.com/terms/m/mrr.asp

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