CPM, CTR, CPC, CPA and ROAS: practical calculations for Tunisian merchants
These abbreviations do not replace a profit calculation. They help identify which question each number answers. CPM describes exposure cost, CTR relates clicks to impressions, CPC gives the cost of a click, CPA gives the cost of a defined action, and ROAS compares attributed conversion value with advertising spend. The mistake is
These abbreviations do not replace a profit calculation. They help identify which question each number answers. CPM describes exposure cost, CTR relates clicks to impressions, CPC gives the cost of a click, CPA gives the cost of a defined action, and ROAS compares attributed conversion value with advertising spend. The mistake is combining different definitions, periods or currencies and then treating the result as a reliable business decision.
Fix the unit, period and action
Before calculating, record currency, dates and reporting level: campaign, ad set or advertisement. Identify the selected click measure, such as all clicks, link clicks or outbound clicks. For CPA, the action might be a message, submitted order or delivery. Each calculation is possible, but the word acquisition does not automatically mean a customer paid and received a parcel.
For foreign-currency spending, retain the original amount and your actual conversion cost instead of using an invented or remembered exchange rate. Separate payment charges and other expenses when helpful. That explains why the platform’s expenditure may differ from the advertising cost recorded by your business.
Understand the basic formulas
| Measure | Calculation | Does not establish |
|---|---|---|
| CPM | Spend ÷ impressions × 1000 | Orders or profit |
| CTR | Selected clicks ÷ impressions × 100 | Order quality |
| CPC | Spend ÷ selected clicks | Delivery cost |
| CPA | Spend ÷ defined actions | Profit from an unfinished action |
| ROAS | Attributed value ÷ spend | Net margin or collection |
If the denominator is zero, do not record a zero cost. With no orders, cost per order cannot be calculated. State that spending occurred but no such outcome has been observed. A zero cell would misleadingly suggest that acquisition was free.
One fictional example connecting the numbers
Suppose 120 TND buys 20000 impressions and 300 link clicks. CPM is 6 TND, CTR is 1.5% and CPC is 0.400 TND. Suppose there are then 12 submitted orders and 8 deliveries. Advertising costs 10 TND per submitted order or 15 TND per delivery. Spending has not changed; the action name and CPA denominator have.
At 55 TND per order, submitted value is 660 TND, giving a value-to-spend ratio of 5.5. Eight deliveries represent 440 TND, or approximately 3.67 times the expenditure. Do not automatically call the latter the platform’s ROAS unless it genuinely uses that attributed value and definition. Your internal worksheet can call it delivered value divided by advertising spend. These educational figures are not Tunisian advertising prices or performance benchmarks.
Why ROAS cannot establish profit
Suppose each delivered order contributes 18 TND before advertising after certain known costs. Eight deliveries contribute 144 TND, leaving 24 TND after 120 TND in advertising, before expenses not yet included. Failed-delivery shipping or additional charges may reduce or eliminate that remainder. A high value ratio can coexist with a loss because revenue and contribution are different.
Organize orders and costs in Matjri and compare delivery outcomes alongside advertising columns. Check that the purchasing prices and expenses you use are complete. A missing cost is not a zero cost. Likewise, a delivered order does not necessarily mean the courier’s settlement has already reached your account.
A weekly review method
- Align period and currency, then identify the campaign or product.
- Verify click definitions and the commercial action being counted.
- Recalculate ratios from original counts to confirm the denominator.
- Group comparable orders and allow their outcomes to mature.
- Review delivery, commercial contribution and cash before recording one actionable decision.
A rising CPM does not automatically establish failure; response and final outcomes still matter. A falling CPC accompanied by more cancellations has not solved order quality. When advertising reports disagree with order records, examine definitions, attribution and timing rather than adding separate reports as though they independently count the same thing.
Keep a small, understandable worksheet
A beginner’s sheet can contain spend, impressions, defined clicks, orders, confirmations, deliveries, value and known costs. Add a note about changes or missing information, such as delayed settlement, a new image or an unentered cost. Many indicators are not useful if nobody knows what action a change would justify. Select the measure for the question, then inspect the outcome that matters to the business.
Your next step is recalculating one week from raw figures. If you are starting, bring product and order records together in Matjri rather than comparing a known expense with an undocumented commercial result. Clear definitions make arithmetic useful; a foreign abbreviation does not make it reliable on its own.
Frequently asked questions
What is a good CTR in Tunisia?
No single number applies to every product, audience and click definition. Compare similar circumstances alongside delivered orders. A general benchmark is neither a promised target nor independent proof of success.
Is order CPA the final customer acquisition cost?
Only with a clearly stated definition. A submitted order differs from a delivered order, and one customer may order repeatedly. State the denominator so the team understands what the number represents.
Does ROAS mean multiplied profit?
No. It compares attributed value with spending and does not automatically deduct product purchasing, delivery or returns. Calculate contribution and collection separately before increasing your budget or committing more cash.
Sources and review
Editorial review: 15 October 2026. Numerical examples are illustrative learning exercises, not promised results or market prices.