Customer Acquisition Cost Calculator

Ask how much it costs to win a customer and the usual answer is ad spend divided by sign-ups. That number is real, but it leaves out the salespeople, the marketing team, the tools and the agency that also went into every new customer, and it can be several times too low. Customer Acquisition Cost Calculator adds those costs back and shows both figures side by side, so you can see how much the simple version flatters you.

Enter ad spend, then each other sales and marketing cost for the same period as its own line, and the number of new customers you won. You get the fully-loaded CAC, the ad-only CAC, paid CAC if you know how many customers came from ads, and the months it takes a customer to pay back their CAC if you add revenue and gross margin. A bar for every cost line shows where each customer's cost actually goes.

Worked Example: A SaaS Month

The page opens on one month for a software company: 12,000 USD of ads, plus 18,000 of sales salaries, 9,000 of marketing salaries, 1,500 of tools and 3,000 of agency fees, for 85 new customers. Fully-loaded CAC is $511.76 (43,500 ÷ 85). Ad-only CAC is $141.18, which “leaves out 72.4% of the real cost”. Forty customers came from ads, so paid CAC is $300.00. At 120 a month per customer and an 80% margin, payback takes 5.3 months. Sales salaries turn out to be the biggest line, $211.76 of every customer's cost.

Press Load Sample for an online shop in euros, where ads are most of the cost and the gap is 30.9%, and then a business selling to companies, in pounds, where salaries and events push CAC to £7,375 and the ad-only figure misses 83.1%. Copy summary gives one paragraph with all the figures and how they were reached, ready for a report.

The Four CAC Formulas

• Fully-loaded (blended) CAC = all sales and marketing costs ÷ new customers. This is the number to compare with customer lifetime value.
• Ad-only CAC = ad spend ÷ new customers. Useful for media buying, misleading as the cost of growth.
• Paid CAC = ad spend ÷ customers that came from paid ads. It shows what ads cost when the free customers are taken out.
• CAC payback = fully-loaded CAC ÷ (monthly revenue per customer × gross margin). Without a margin the tool assumes 100%, which shortens the payback.

The arithmetic was checked against exact fractions in Python on 284 random combinations of costs and customers. To set CAC against lifetime value, the Customer Lifetime Value Calculator works out LTV three ways and the LTV to CAC ratio.

Limits of One CAC Number

• Timing: costs and customers must cover the same period. A long sales cycle means this month's spend wins next quarter's customers, so a single month can look worse or better than it is.
• Salaries: count only the share of each person's time spent winning new customers, not account management or support.
• Customers: new customers must be a whole number of at least 1. A paid-customer count above the total is refused with “Customers from paid ads cannot be more than all new customers.”
• Amounts can include thousands separators such as 18,000, but not a currency sign: $12k returns “Ad spend must be a number without a currency sign, such as 12,000 or 1500.50.”