Hong Life CalculatorsUnderstanding the cost-per-sale (CPS) advertiser cost calculator — concept and principle
In cost-per-sale (CPS) or affiliate marketing, an advertiser pays partners a commission only when a referred customer buys. Many programmes run through an affiliate network or agency that adds its own fee, often expressed as a percentage of the commissions paid. This calculator adds both layers and shows the total cost of the programme and what share of the referred sales it consumes. It works with any currency; the default example uses US dollars.
How it is calculated
Let S be the number of sales, A the average order value, r the partner commission rate in percent and g the network or agency fee as a percentage of commission.
- Partner commissions c = S × A × r/100
- Network fee = c × g/100
- Total cost = c + c × g/100 = c × (1 + g/100)
- Cost as % of sales = total cost ÷ (S × A) × 100, which simplifies to r × (1 + g/100)
The principle
CPS shifts risk from the advertiser to the partner: you pay only for completed sales, so the cost scales with revenue. Because the network fee is charged on top of the commission rather than on sales, it acts as a multiplier. A 30% override on an 8% commission does not cost 30% of sales; it raises the effective rate from 8% to 8 × 1.3 = 10.4% of sales.
Worked example
- Inputs: 400 sales, average order $60, commission 8%, network fee 30% of commission.
- Referred sales = 400 × 60 = $24,000.
- Partner commissions = 24,000 × 0.08 = $1,920.00.
- Network fee = 1,920 × 0.30 = $576.00.
- Total cost = 1,920 + 576 = $2,496.00; cost as % of sales = 2,496 ÷ 24,000 = 10.4%.
How to read the result
Compare the cost as a percentage of sales with your gross margin. If your gross margin is 40%, a 10.4% acquisition cost leaves room for profit; if your margin is 12%, almost nothing is left after fulfilment. Also consider returns and cancellations, since commissions on refunded orders are sometimes reversed and sometimes not, depending on the programme terms.
Common mistakes
- Treating the network fee as a percentage of sales instead of a percentage of commission.
- Using order value including tax and shipping when the commission is paid on the net product amount.
- Forgetting fixed costs such as platform setup fees, monthly minimums or bonus payments to top partners.
- Assuming all affiliate sales are incremental; some customers would have bought anyway.
Frequently asked questions
What is a network override?
It is the network's or agency's fee, charged as a percentage of the commissions you pay to partners, on top of those commissions.
Is CPS the same as affiliate marketing?
Affiliate marketing usually uses CPS, but programmes can also pay per lead or per install. CPS specifically means payment per completed sale.
How do I set a sustainable commission rate?
Work backwards from your gross margin: decide what share of each sale you can spend on acquisition, then divide by (1 + network fee) to find the maximum partner commission.
Sources: Paul W. Farris et al., Marketing Metrics: The Definitive Guide to Measuring Marketing Performance (Pearson)