Customer acquisition cost: how to calculate it and what it should be

Aug 18
3 min read

Updated: 4 days ago

Introduction

Customer acquisition cost is what you spend, on average, to turn a stranger into a paying customer. It is one of two numbers that decide whether growth makes you money — the other being what a customer is worth once you have them.

Plenty of businesses track cost per click or cost per lead instead. Those are easier to see and much less useful, because neither tells you whether the customers you are buying cost less than they return.

1. How to calculate customer acquisition cost

The formula is straightforward:

Customer acquisition cost = total acquisition spend ÷ new customers acquired

Spend $3,000 in a month and gain 60 new customers, and your acquisition cost is $50.

The arithmetic is not where people go wrong. The inputs are.

2. The costs most businesses leave out

An acquisition cost built only from ad spend will always look better than reality. Include:

Ad spend — the obvious component.
Tools used specifically to acquire customers.
Agency or freelancer fees attributable to acquisition work.
Staff time spent on acquisition, at a realistic hourly cost.
Discounts on first purchase, which are an acquisition cost even though they never appear as one. A $10 introductory offer given to 60 new customers is $600 of acquisition spend.

That last item is the one most often missed, and it is frequently large enough to change the answer.

3. Count new customers, not orders

If a customer buys three times in the month you measured, they are one acquired customer, not three. Counting orders will understate your cost, sometimes dramatically.

Also fix your attribution window before you start. Someone who first saw an advert in March and bought in May belongs to whichever month your rule assigns them to — but the rule has to exist and stay consistent, or the number will move for reasons that have nothing to do with performance.

4. What a healthy acquisition cost looks like

There is no universal benchmark, and any article quoting one is guessing about your business. The only meaningful comparison is against your own customer lifetime value.

Work out the gross profit an average customer produces over their whole relationship with you. Acquisition cost must sit below that figure, and comfortably below it — a common working rule is a third or less, which leaves room for overheads and for the estimate being wrong.

If a customer produces $150 in gross profit, then $50 acquisition cost is sound, $100 is fragile, and $150 is a business that grows and loses money at the same time.

5. How to bring it down

There are three routes, and only one of them is about advertising.

Improve conversion before improving traffic

If your landing page converts 2% and you lift it to 3%, acquisition cost falls by a third with no change in spend. This is usually the cheapest available improvement and it is where most businesses look last.

Sharpen the offer

A weak offer makes every channel expensive. If acquisition cost is high across all channels, the problem is rarely the channels — it is that what you are proposing is not compelling enough at the price.

Reduce the discount you lead with

Since first-purchase discounts are acquisition spend, a smaller introductory offer that still converts lowers the number directly. Test this rather than assuming a deeper discount is needed.

Only after those three is bidding and targeting optimisation worth much attention.

6. Segment it, or it will mislead you

A single blended acquisition cost hides everything useful. Calculate it per channel, and where possible per customer type.

Blended $50 might be one channel producing customers at $22 and another at $140. The average looks acceptable while half your budget loses money. You cannot see that without splitting the number, and you cannot split it without the instrumentation to record where each customer came from.

Conclusion

Customer acquisition cost is only meaningful next to customer lifetime value. On its own it is a figure without a pass mark.

Calculate it honestly — including discounts and staff time — count customers rather than orders, split it by channel, and compare it to the gross profit a customer actually produces. Then improve conversion and the offer before touching bids, because those two move the number further for less money.