The CAC Calculator divides what you spent acquiring customers by how many you acquired, and, if you add average revenue per user and gross margin, tells you how many months each customer takes to pay their acquisition cost back. Enter sales expenses, marketing expenses, and the number of new customers from the same period.
How It Works
The calculator also reports a marketing-only CAC (marketing spend divided by new customers) so you can see the paid-demand figure separately from the fully loaded one. With ARPU and gross margin supplied, monthly gross profit per customer is ARPU times margin, and the payback period is CAC divided by that figure. Payback within 12 months rates as the healthy benchmark, 12 to 18 as a warning zone, and beyond that as a problem the verdict text will name.
Parameters
| Input | Required | Meaning | |---|---|---| | Sales expenses | No | Sales salaries, commissions, and tools for the period (defaults to 0) | | Marketing expenses | Yes | Ads, agency, content, and campaign costs | | New customers | Yes | Customers acquired in the same period; at least 1 | | ARPU | No | Average monthly revenue per user, for payback | | Gross margin | No | Percent, for payback |
Worked example
A company spends 70,000 on marketing in a quarter and acquires 250 customers. Fully loaded CAC is 100,000 / 250 = **280. With ARPU of 41.25 of monthly gross profit, so payback is 400 / 41.25 = 9.7 months, inside the healthy band. The two CAC figures answer different questions: 280 evaluates the marketing engine against other channels.
What to include, honestly
Fully loaded CAC includes the people: salaries and commissions of the teams doing the acquiring, agency retainers, advertising, acquisition software, and content produced for acquisition. The two classic cheats are excluding salaries ("our team is a fixed cost anyway") and mismatching periods (this quarter's spend against last quarter's customers). Both make CAC look better while making decisions worse. Early-stage companies sometimes track a marginal CAC (paid spend only) alongside the loaded figure for channel decisions; label which one you are quoting, because the gap between them is commonly twofold.
CAC is half of a ratio
Alone, CAC says nothing about whether acquisition is worth it; the partner metric is lifetime value. The common orientation is LTV to CAC of at least 3 to 1 with payback inside a year for subscription businesses, tighter for low-margin or high-churn models. A 2,000 LTV and ruinous against a $500 one. Pair this calculator with the LTV and churn tools on this site using the same period and customer definition, or the ratio compares strangers.
Limitations
The model treats the period's spend as causing the period's customers, which lags and attribution make approximate; brand spend pays off over quarters, not weeks. It cannot split CAC by channel (compute per channel by entering that channel's spend and customers), and it uses averages, so a mix shift toward enterprise or self-serve customers can move CAC without any efficiency change. Estimates for planning, not audited metrics.
Channel CAC versus blended CAC
Blended CAC hides the channel story. Compute CAC per channel with this same formula (channel spend plus an honest share of team cost, divided by customers attributed to that channel) and a pattern usually appears: one channel at half the blended figure subsidizing another at triple. Budgets follow that table, not the blend. Two cautions keep channel CAC honest: attribution windows must match across channels, and brand or organic customers acquired with no channel should still carry their share of team cost in the blended figure, or the channel table will flatter every paid channel at once.
Frequently Asked Questions
Should CAC include salaries?
For the fully loaded figure investors expect, yes: the acquiring teams' compensation is the largest acquisition cost in most B2B companies. Track a paid-only CAC separately if you need it for channel tuning.
What is a good CAC payback period?
Twelve months or less is the standard SaaS benchmark, and the calculator rates it accordingly. Capital-efficient and bootstrapped companies often demand six months or less; well-funded category leaders may accept eighteen with strong retention evidence.
Why did our CAC jump this quarter?
Usually a mix or timing artifact: a big brand campaign expensed now for later pipeline, a seasonal customer dip, or enterprise mix raising both spend and deal size. Check the per-channel and per-segment CAC before concluding efficiency fell.