Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
CAC payback period
7.7
Monthly gross profit per customer
$1,170
Annual gross profit per customer
$14,040
CAC used in calc
$9,000
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How to use this
- 1Enter fully loaded cac per customer ($).
- 2Enter annual contract value (acv) ($).
- 3Enter gross margin (%).
- 4Read your cac payback period on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
CAC payback period tells you how many months of gross margin from a customer it takes to recover the fully loaded cost of acquiring them. It's the metric that determines how much cash you tie up before a customer becomes cash-flow positive on your books, which matters enormously for how fast you can reinvest in growth without external capital. Best-in-class SaaS runs 5-12 month payback; 12-18 months is workable for enterprise motions with high ACVs and strong retention; beyond 24 months, the capital intensity of growth becomes hard to sustain without either raising more money or slowing down. Payback period and LTV:CAC measure related but distinct things — payback is about cash-flow timing and capital efficiency, while LTV:CAC is about lifetime unit economics. A company can have a great LTV:CAC ratio and still run out of cash if payback period is too long relative to its burn rate and fundraising cadence.
Worked example
Using the values the calculator loads with:
Inputs
- Fully loaded CAC per customer: 9000 $
- Annual contract value (ACV): 18000 $
- Gross margin: 78 %
Results
- CAC payback period: 7.7
- Monthly gross profit per customer: $1,170
- Annual gross profit per customer: $14,040
- CAC used in calc: $9,000
What each field means
Inputs
- Fully loaded CAC per customer ($)
- The fully loaded cac per customer used in the calculation, measured in $. Starts at 9000 $ so you have a working example on load.
- Annual contract value (ACV) ($)
- The annual contract value (acv) used in the calculation, measured in $. Starts at 18000 $ so you have a working example on load.
- Gross margin (%)
- The gross margin used in the calculation, measured in %. Starts at 78 % so you have a working example on load. Accepted range: 1–100 %.
Results
- CAC payback period
- Returned as a length of time and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly gross profit per customer
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual gross profit per customer
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- CAC used in calc
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What's considered a good CAC payback period?
5-12 months is excellent, typical of efficient PLG or SMB motions with fast sales cycles. 12-18 months is fine for mid-market or enterprise where deal sizes are bigger. Beyond 18-24 months, you're tying up a lot of cash per customer and need strong balance sheet or funding to sustain growth at scale.
Should CAC payback use gross margin or full revenue?
Always use gross profit, not revenue — you can't spend the cost-of-goods-sold portion of revenue on anything, including recovering CAC. Using raw revenue overstates how fast you actually recoup acquisition spend and can mask a hosting-cost or support-cost problem hiding inside gross margin.
How does payback period interact with churn?
If your average customer churns before payback completes, you never recover the acquisition cost at all — you lost money on that customer. Compare payback period against your average customer lifetime; payback should be comfortably shorter, ideally by 2-3x, to leave room for actual profit.
What counts as fully loaded CAC?
All sales and marketing costs (salaries, commissions, ad spend, tools, events) divided by new customers acquired in the period — not just ad spend or commission alone. Leaving out salaries or overhead is the most common way companies understate CAC and overstate payback efficiency.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
LTV:CAC Ratio Calculator
Compare the lifetime value of a customer against what it costs to acquire them.
Sales Magic Number Calculator
Measure how much new ARR your sales and marketing spend produces.
SaaS Gross Margin Calculator
Calculate true gross margin including hosting, support, and infrastructure costs.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). CAC Payback Period Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/cac-payback-period
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/cac-payback-period" target="_blank" rel="noopener">CAC Payback Period Calculator — RevenueLab</a> (2026).</p>
Source: [CAC Payback Period Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/cac-payback-period) (2026).