The customer acquisition cost formula
CAC = (ad spend + other acquisition costs) / new customers acquired
The calculator above also returns two related numbers:
Cost per lead = (ad spend + other acquisition costs) / leads
Lead to customer rate = new customers / leads
Use the same period for every input. If spend is for October, count the customers and leads from October too. The calculator shows the formula filled in with your numbers, so you can check the math or paste it into a report.
How to calculate customer acquisition cost
- Pick a period. A month or a quarter is common. Short periods are noisy when you win few customers.
- Add up ad spend. Everything you paid ad platforms in that period: Google Ads, Meta Ads, LinkedIn and the rest.
- Add other acquisition costs. Anything you would not have spent if you stopped acquiring customers (see the next section).
- Count new customers. Only customers who paid for the first time in that period. Renewals and upgrades of existing customers do not count.
- Divide. Total cost over new customers is your CAC.
- Add leads if you track them. That gives you cost per lead and the lead to customer rate, which tell you where the cost comes from.
What to include in acquisition costs
A CAC that only counts ad spend is sometimes called paid CAC. It is useful per channel, but it hides the real cost of growth. A fuller (blended) CAC also includes:
- Tools used for acquisition, such as ad management, landing page builders, email and analytics.
- Salaries for the time people spend on marketing and sales. If someone splits their time, count only the share spent on acquisition.
- Agency and freelancer fees for ads, content or design.
- Content and creative production, such as videos and ad creatives.
Leave out costs that serve existing customers, such as support and account management. Those belong to retention, not acquisition. Whatever you choose, keep the same definition every period, or the trend means nothing.
Worked example
This example uses made up numbers to show the math.
A startup spends 4,000 USD on ads in one month. It also pays 1,000 USD for tools and a share of a marketer's time. The ads bring 200 leads, and 20 of them become paying customers.
| Input | Value |
|---|---|
| Ad spend | 4,000 USD |
| Other acquisition costs | 1,000 USD |
| Leads | 200 |
| New customers | 20 |
- Total cost: 4,000 + 1,000 = 5,000 USD
- CAC: 5,000 / 20 = 250 USD per customer
- Cost per lead: 5,000 / 200 = 25 USD per lead
- Lead to customer rate: 20 / 200 = 10%
Counting ad spend alone, CAC would be 4,000 / 20 = 200 USD. The 50 USD difference is the cost the ad dashboard never shows.
CAC vs cost per lead vs cost per activated user
These three numbers measure different points in the same funnel.
| Metric | Formula | What it tells you |
|---|---|---|
| Cost per lead | Total cost / leads | How cheaply you get people to raise their hand |
| Cost per activated user | Total cost / users who reach the activation step | How cheaply you get people to actually use the product |
| Customer acquisition cost | Total cost / new paying customers | What a paying customer costs you |
Cost per lead is the fastest signal but the easiest to game. A campaign with cheap leads that never buy can look great on cost per lead and terrible on CAC. Cost per activated user sits in between and is useful for products with a free trial or a free tier, where activation predicts payment better than signup. Define activation as one concrete step, such as creating a first project.
How to lower customer acquisition cost
- Cut spend that brings no qualified leads. Find the campaigns and keywords that spend without producing leads worth talking to, and pause them first.
- Improve the lead to customer rate. A better landing page, a faster reply to new leads or a clearer pricing page lowers CAC without touching ad spend.
- Fix the funnel step with the biggest drop. Look at your conversion funnels and work on the step where most people leave.
- Tag every link. Untagged traffic shows as direct, so good channels look worse and you may cut the wrong ones. Use the UTM builder.
- Compare channels on the same definition. Paid CAC per channel, blended CAC for the business.
How Orwel ties spend to qualified leads
CAC tells you the total. To act on it you need the number per campaign, and that requires knowing which campaign each lead came from.
Orwel's SDK captures UTM parameters and ad click IDs on landing, keeps the first and last touch across sessions, and attaches them to every conversion. With Google Ads or Meta Ads connected, Orwel syncs campaign cost and ties each lead to the campaign that paid for it. The Campaigns screen shows cost, leads, qualified leads, cost per lead, cost per qualified lead and campaigns that spent with no qualified leads. Each lead also has a score from 0 to 100 and its session history, in leads and intent signals.
Read the guide to UTM tracking and marketing attribution to set it up end to end.