Is target CPA the same as CAC?

No, and the difference matters. CPA (cost per acquisition) here means advertising cost per order — every order, including repeat purchases from existing customers. CAC (customer acquisition cost) means advertising cost per newly acquired customer, which is a higher number because only some orders come from first-time buyers. This calculator is order-level, so it produces a target CPA, not a target CAC.

Should target CPA be per order or per customer?

This calculator works per order, which is the safe default because it only relies on the economics of the order in front of you. Moving to a customer-level target CAC — where you allow yourself to pay more than the first order contributes — requires reliable repeat-purchase and lifetime-value data.

What if my desired margin makes CPA negative?

It means the margin you want is larger than the contribution the order generates before advertising. Either lower the target margin, raise the price, or reduce variable costs — no acquisition budget exists at that combination.

Does target CPA include fixed costs?

No. Set your desired contribution margin high enough that what remains after acquisition covers your fixed costs.

Target CPA Calculator

Target CPA is the most you can pay to acquire an order and still hit the contribution margin you want. Enter the price your customer pays, your variable costs and your desired margin to get the acquisition ceiling your campaigns should respect.

Selling price

€

Price includes VAT?

VAT / sales tax rate

€79.00 including 21% VAT = €65.29 net revenue.

COGS

€

Shipping

€

Packaging & handling

€

Other variable costs

€

Per-order app fees, inserts, returns provision.

Average payment fee

Your average effective transaction rate.

Average fixed payment fee

€

Payment cost: €1.44 per order.

Payment fees vary by payment method, Shopify plan, country, card type and payment provider. Use your average effective transaction fee for the most realistic estimate.

Desired contribution margin

Share of net revenue you want left after advertising.

€21.10

Maximum target CPA

Spending less than €21.10 per acquired order should leave room for your target contribution margin, based on the costs entered.

Net revenue per order: €65.29
Variable costs per order: €31.13
Contribution before advertising: €34.15
Contribution margin before advertising: 52.3%
Break-even CPA (0% margin): €34.15
ROAS needed at this CPA: 3.09×

How we calculated this

Selling price incl. VAT: €79.00
VAT: − €13.71
Net revenue: €65.29
COGS: − €24.00
Shipping: − €4.50
Packaging & handling: − €1.20
Payment fees: − €1.44
Other variable costs: − €0.00
Contribution before advertising: €34.15

Payment fees are charged on the full amount collected from the customer, VAT included. Fixed costs such as salaries, rent and software are not part of this calculation.

What is target CPA?

Cost per acquisition (CPA), also called cost per order, is what you pay in advertising for one order — not per new customer, which is customer acquisition cost (CAC). Your target CPA is the ceiling: the contribution the order generates before advertising, minus the contribution profit you want to keep. Anything spent above it turns a profitable order into an unprofitable one.

How is target CPA calculated?

Contribution before advertising = net revenue − COGS − shipping − packaging − payment fees − other variable costs

Target CPA = contribution before advertising − (net revenue × desired margin)

Net revenue excludes VAT where the selling price includes it, and the desired margin is expressed as a percentage of net revenue so it stays comparable with your contribution margin.

Example

A €79.00 product including 21% VAT gives €65.29 of net revenue. With €31.13 of variable costs, contribution before advertising is €34.15. Wanting a 20% contribution margin means keeping €13.06 per order, so the maximum target CPA is €21.10. If an ad platform reports a cost per purchase above that, those orders are under water.

Why this matters for ecommerce stores

Ad platforms optimise toward whatever CPA target you give them. Setting that target from your margin instead of from habit is the difference between scaling profitably and scaling into a loss you notice a month later.

Frequently asked questions

Is target CPA the same as CAC?: No, and the difference matters. CPA (cost per acquisition) here means advertising cost per order — every order, including repeat purchases from existing customers. CAC (customer acquisition cost) means advertising cost per newly acquired customer, which is a higher number because only some orders come from first-time buyers. This calculator is order-level, so it produces a target CPA, not a target CAC.
Should target CPA be per order or per customer?: This calculator works per order, which is the safe default because it only relies on the economics of the order in front of you. Moving to a customer-level target CAC — where you allow yourself to pay more than the first order contributes — requires reliable repeat-purchase and lifetime-value data.
What if my desired margin makes CPA negative?: It means the margin you want is larger than the contribution the order generates before advertising. Either lower the target margin, raise the price, or reduce variable costs — no acquisition budget exists at that combination.
Does target CPA include fixed costs?: No. Set your desired contribution margin high enough that what remains after acquisition covers your fixed costs.

Your maximum CPA isn't a fixed number.

Connect Shopify to track your real costs and understand how much you can afford to spend acquiring an order.

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Related calculators

Break-even ROAS Calculator — the ROAS you need before ads become profitable
Contribution Margin Calculator — what's left per sale after variable costs
Customer Lifetime Value Calculator — what a customer is worth over their lifetime
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