What this tool does
This is a free, browser-only SaaS metrics calculator. It takes six inputs any SaaS founder or operator already knows — customer count, average revenue per customer, monthly churn rate, gross margin, CAC and net-new customers per month — and turns them into the eight numbers investors and operators actually track: MRR, ARR, ARPU, churn rate, LTV, CAC, the LTV:CAC ratio, CAC payback period and quick ratio. Unlike a plain formula sheet, every result is labeled good, watch or red flag against real sector benchmarks, and the tool projects your MRR forward 12 months so you can see where your current churn and growth rate actually lead.
How to use it
Fill in your active customer count and average monthly revenue per customer (ARPU) — these two alone produce MRR and ARR. Add your monthly churn rate and gross margin to unlock LTV. Add CAC (blended sales + marketing spend divided by new customers acquired) to get the LTV:CAC ratio and CAC payback period. Add net-new customers per month to see quick ratio and the 12-month MRR projection table. Every field recalculates live — there is no submit button and nothing leaves your browser.
The formulas behind each metric
MRR = customers × ARPUARR = MRR × 12LTV = (ARPU × Gross Margin %) / Monthly Churn Rate— gross-margin-adjusted lifetime value in currency, not monthsLTV:CAC = LTV / CACCAC Payback (months) = CAC / (ARPU × Gross Margin %)Quick Ratio = (Net-new customers/mo × ARPU) / (MRR × Monthly Churn Rate)— new MRR added versus MRR churned in the same month
Example 1 — healthy mid-market SaaS
Input
Customers: 400 ARPU: $79/mo Monthly churn: 3% Gross margin: 80% CAC: $450 Net-new customers/mo: 30
Output
MRR = 400 × 79 = $31,600 ARR = 31,600 × 12 = $379,200 LTV = (79 × 0.80) / 0.03 = 63.20 / 0.03 = $2,106.67 LTV:CAC = 2,106.67 / 450 = 4.68 : 1 → good (≥3, below the 5+ "maybe underspending" zone) CAC payback = 450 / (79 × 0.80) = 450 / 63.20 = 7.12 months → good (<12) Quick ratio = (30 × 79) / (31,600 × 0.03) = 2,370 / 948 = 2.50 → growing net of churn (>1)
Example 2 — leaky bucket, too expensive to acquire
Input
Customers: 150 ARPU: $25/mo Monthly churn: 8% Gross margin: 65% CAC: $380 Net-new customers/mo: 8
Output
MRR = 150 × 25 = $3,750 ARR = 3,750 × 12 = $45,000 LTV = (25 × 0.65) / 0.08 = 16.25 / 0.08 = $203.13 LTV:CAC = 203.13 / 380 = 0.53 : 1 → red flag (losing money per customer acquired) CAC payback = 380 / (25 × 0.65) = 380 / 16.25 = 23.4 months → red flag (>18) Quick ratio = (8 × 25) / (3,750 × 0.08) = 200 / 300 = 0.67 → shrinking (<1): churn is outrunning new bookings
Benchmarks — what counts as good
| Metric | Red flag | Watch | Good |
|---|---|---|---|
| LTV:CAC ratio | < 1:1 | 1–3:1 | ≥ 3:1 (5:1+ may mean under-investing in growth) |
| CAC payback period | > 18 months | 12–18 months | < 12 months (<6 excellent, PLG-typical) |
| Monthly churn — enterprise | > 2% | 1–2% | < 1% |
| Monthly churn — SMB / mid-market | > 7% | 3–7% | < 3% |
| Quick ratio | < 1 (shrinking) | 1–4 | > 4 |
| Gross margin | < 60% | 60–75% | > 75% |
These bands are directional, drawn from widely cited SaaS benchmark studies — always compare against your own segment (enterprise vs. SMB vs. consumer subscription behave very differently) rather than treating any single number as a universal pass/fail.
FAQ
What is a good LTV:CAC ratio for a SaaS company?
3:1 or higher is the widely used baseline for a healthy SaaS business: every dollar spent acquiring a customer returns at least three dollars of gross-margin lifetime value. Above 5:1 is excellent but can also signal under-investment in growth, since you could likely spend more on acquisition and still be profitable. Below 3:1 means acquisition is expensive relative to what customers return, and below 1:1 you are losing money on every customer you sign.
How is LTV calculated in this tool?
LTV = (ARPU × Gross Margin %) / Monthly Churn Rate. This is the standard gross-margin-adjusted formula: it multiplies average revenue per user by your gross margin to get gross profit per customer per month, then divides by monthly churn rate to get the expected number of months a customer stays, producing lifetime gross profit. Omitting gross margin overstates LTV because it counts revenue you never actually keep.
What counts as a healthy monthly churn rate?
It depends heavily on who you sell to. Enterprise SaaS with annual contracts typically runs under 1% monthly churn (under 12% annual). Mid-market and SMB SaaS commonly sees 2-5% monthly churn. Self-serve, low-price or consumer subscription products often run 5-10% monthly and can still be viable if CAC is low and LTV:CAC still clears 3:1. There is no single universal target — benchmark against your own segment, not SaaS overall.
What is CAC payback period and why does it matter?
CAC payback period is how many months of gross profit from a customer it takes to recover what you spent acquiring them: CAC / (ARPU × Gross Margin %). Under 12 months is considered healthy for most SaaS, under 5-6 months is excellent and typical of efficient product-led-growth motions, and over 18 months is a red flag because it ties up cash for a long time and makes the business fragile to churn shocks before payback completes.
What is quick ratio in a SaaS context?
SaaS quick ratio (popularized by SaaStr) measures growth efficiency: new MRR added divided by MRR lost to churn in the same period. This tool computes it as (net-new customers/month × ARPU) / (MRR × monthly churn rate). A quick ratio above 4 is considered excellent, above 1 means you are still growing net of churn, and below 1 means churn is outrunning new bookings and MRR is shrinking.
Does this tool store or upload my numbers?
No. Every calculation — MRR, ARR, LTV, CAC payback, quick ratio and the 12-month projection — runs in plain JavaScript in your browser. Nothing is sent to a server, there is no signup, and the page keeps working with your network disconnected, which makes it safe to plug in real unreleased revenue and cost figures.
Why does the 12-month projection sometimes flatten out instead of growing forever?
The projection applies churn to your existing customer base every month and then adds your net-new customers/month on top. If churn (in customers) roughly equals or exceeds new customers added, the customer count — and therefore MRR — approaches a steady state or declines instead of compounding, which is exactly what happens in a real leaky-bucket SaaS business until acquisition outpaces the leak.