Deepak Gupta

Free interactive tool

SaaS Metrics Calculator

Enter a few numbers you already track and see the unit economics investors ask about: LTV on a gross-margin basis, LTV:CAC, CAC payback, churn, retention and where your MRR is heading. Each result is checked against published benchmarks.

Your numbers

Monthly recurring revenue$Active customersMonthly customer churn%Gross margin%

Acquisition

CAC per customer$Monthly sales & marketing spend$Optional. With new customers, derives CACNew customers per monthMonthly expansion MRR%Upsells as a share of MRR

Segmentsets the payback target

LTV:CAC

watch

2.6:1

Target 3:1 or better

CAC payback

risk

19.2 mo

Target under 12 months

Customer lifetime value

$15,600

Gross-margin basis · revenue basis $20,000

CAC

$6,000

As entered

ARR

$576,000

ARPA $400 a month

Customer lifetime

50 mo

Annual churn 21.5%

Gross revenue retention

watch

78.5%

Bessemer: 85 to 90% is typical

Net revenue retention

78.5%

Above 100% means expansion outpaces churn

MRR over the next 24 months$48K today → $68K

Dashed line: where MRR settles ($100,000) when new revenue equals revenue lost to churn, net of expansion.

How each number is calculated

ARPA: MRR ÷ active customers
Customer lifetime: 1 ÷ monthly churn
Annual churn: 1 − (1 − monthly churn)^12, compounded rather than × 12
LTV (gross margin): ARPA × gross margin ÷ monthly churn
CAC: As entered, or monthly sales & marketing spend ÷ new customers
LTV:CAC: LTV ÷ CAC
CAC payback: CAC ÷ (ARPA × gross margin), in months
Gross revenue retention: (1 − monthly churn)^12
Net revenue retention: (1 − monthly churn + monthly expansion)^12
Projection: Each month keeps (1 − churn + expansion) of MRR and adds new customers × ARPA

Retention assumes the customers who churn carry average revenue. Benchmarks come from David Skok's SaaS Metrics guide (LTV at least 3× CAC, payback under 12 months) and Bessemer Venture Partners' Scaling to $100 Million (payback targets by segment, gross retention of 85 to 90%). The watch and risk bands between those lines are rules of thumb, not published thresholds.

FAQ

What is a good LTV:CAC ratio?: David Skok's widely used rule of thumb is at least 3:1, with CAC recovered in under 12 months. The calculator marks 3:1 or better as healthy, 1:1 to 3:1 as watch, and below 1:1 as risk.
Why does LTV use gross margin?: Revenue is not profit. Serving a customer costs hosting, support and payment fees, so LTV is measured on the margin each customer contributes. The revenue-basis figure is shown alongside for comparison.
What is a good CAC payback period?: Bessemer Venture Partners suggests under 12 months for SMB-focused companies, under 18 for mid-market and under 24 for enterprise, measured on gross margin. Pick your segment and the calculator uses that target.
Why is annual churn not monthly churn × 12?: Churn compounds. At 2% a month you lose 2% of a shrinking base each month, which is about 21.5% a year, not 24%. The calculator compounds it.
Is my data stored anywhere?: No. Everything is calculated in your browser. Your numbers only appear in the page address so you can bookmark or share a scenario.