CAC & Payback Calculator
What each new customer costs to win, channel by channel — and how fast they pay it back.
CAC by channel
| Channel | CAC | Payback | LTV:CAC | Spend | New customers |
|---|
The bar compares each channel’s CAC with the dearest one. Payback is in months, from the gross margin of the revenue per customer. Under the spend and the customers: each channel’s share of the total.
How this was calculated
Source: David Skok, SaaS Metrics 2.0 – Detailed Definitions (CAC, months to recover CAC, LTV:CAC).
Results are estimates for general information and planning, not financial advice. Banks and institutions may calculate differently (rounding, fees, rate changes). Confirm figures with your lender or a qualified adviser before deciding.
About the CAC & Payback Calculator
Customer acquisition cost (CAC) is what it costs to win one new customer. Enter what you spent on each channel in a month (or a quarter or a year) and the new customers each one brought, plus the team, tools and agency costs that belong to no single channel and the customers who came on their own. The calculator gives the blended CAC — all sales and marketing spend ÷ all new customers, the definition David Skok uses — the paid CAC of your channels, and each channel’s CAC side by side.
With the monthly revenue per new customer and your gross margin it adds the months to recover CAC, LTV:CAC from your churn (or an LTV you know) and how much new ARR each unit of spend bought, against Skok’s guidelines: payback under 12 months and LTV:CAC above 3.
How to use it
- Choose the period your figures cover and your currency.
- For each channel, enter the spend and the new customers it brought in the period. Add or remove channels as you need.
- Enter the other sales and marketing costs — salaries and commissions, tools, agencies, content — and the new customers without a paid channel (organic, direct, referrals).
- For the payback and LTV:CAC, enter the monthly revenue per new customer, the gross margin and the monthly churn (or an LTV you know).
- Read the blended and paid CAC, the payback and the channel table; Copy summary or Download CSV.
Examples
Google Ads 12,000 → 48 customers · Meta Ads 8,000 → 25 · LinkedIn Ads 6,000 → 10 · Events 4,000 → 7
Blended CAC = 50,000 ÷ 125 = 400 Paid CAC = 30,000 ÷ 90 = 333.33 By channel: 250, 320, 600 and 571.43
Months to recover CAC = 400 ÷ (50 × 75%) = 10.7 (paid: 8.9) LTV = 37.50 ÷ 3% = 1,250 → LTV:CAC 3.13 New ARR 125 × 50 × 12 = 75,000 → 1.5 per 1 spent
Common uses
- Compare channels and move budget to the ones that win customers cheaply.
- Report CAC, payback and LTV:CAC to investors with the working shown.
- Check that a price or a margin change keeps the payback within 12 months.
- See how much the team’s costs add to the CAC of your ads alone.
Blended, paid and channel CAC
- Blended CAC = all sales and marketing spend ÷ all new customers. It includes salaries, commissions, tools and agencies, and customers who came without an ad. This is Skok’s definition: “Sum of all Sales & Marketing expenses ÷ No of new Customers Added”. It is the figure to use for unit economics and payback.
- Paid CAC = spend on channels ÷ the customers those channels brought. It leaves out organic customers and the team’s costs, so it is lower — it shows what one more customer costs through ads.
- Channel CAC = one channel’s spend ÷ its customers, to move budget towards the channels that win customers cheaply.
Count the costs and the customers of the same period. Skok also suggests that early on you take only part of the salaries of people hired ahead of growth, so the CAC shows what it will be at scale.
Months to recover CAC
Months to recover CAC = CAC ÷ (monthly revenue per customer × gross margin). It says how long a new customer’s margin takes to pay back what they cost to win, and so how much cash growth ties up. Skok’s guideline is under 12 months; he adds that land-and-expand enterprise businesses can work at around 20. The gross margin matters: at 40% margin the same customer takes twice as long to pay back as at 80%.
This payback ignores churn. Customers who leave before the payback never pay back; the LTV calculator shows a churn-adjusted payback.
Source: David Skok, SaaS Metrics 2.0 – Detailed Definitions.
LTV:CAC and new ARR per unit of spend
With a monthly churn the calculator works out a simple LTV — monthly revenue × gross margin ÷ churn — and LTV:CAC, which Skok suggests should be above 3. The new ARR per 1 spent is the annual recurring revenue of the customers won (customers × monthly revenue × 12) ÷ all sales and marketing spend. Skok’s sales efficiency is the same idea with expansion revenue included, measured against the previous quarter’s spend because deals take time to close. Ignoring gross margin, 1.0 means a 12-month payback and 0.5 a 24-month one.
Limitations
- Customers are counted where you attribute them. If several channels touch the same customer, the channel CACs depend on your attribution model; the blended CAC does not.
- Spend and customers should be for the same period; with long sales cycles, compare a period’s customers with the spend of the period before.
- Every channel gets the same LTV here. If customers from some channels churn faster or pay more, work their LTV out separately.
- Payback uses one average revenue per customer; discounts, free trials and annual prepayments change the cash timing.
Privacy
Everything is worked out in your browser. The spend, customers and revenue you enter are never uploaded.
Frequently asked questions
How do you calculate customer acquisition cost?
Divide all sales and marketing spend in a period by the new customers won in that period: 50,000 ÷ 125 = 400. That is the blended (fully loaded) CAC. Paid CAC divides only the channel spend by the customers from those channels.
What is the difference between blended and paid CAC?
Blended CAC counts every cost of winning customers — ads, salaries, tools — and every new customer, organic ones too. Paid CAC counts only the spend on paid channels and the customers they brought, so it is usually lower and shows the cost of one more customer through ads.
What is a good CAC payback period?
David Skok’s guideline is under 12 months, using gross margin: CAC ÷ (monthly revenue per customer × gross margin). He notes that land-and-expand enterprise businesses can work at around 20 months.
Should salaries be part of CAC?
For the blended CAC, yes: the salaries and commissions of the sales and marketing team are part of what it costs to win customers. Enter them under other sales and marketing costs. Skok suggests counting only part of the salaries of people hired ahead of growth when you are small.
What is a good LTV:CAC ratio?
Above 3 in Skok’s guideline. Below 1 each customer costs more to win than they bring in. The LTV calculator works out the LTV three ways and shows the highest CAC that still gives 3:1.