Practical guide · free to read
Your budget starts with your contribution.
Before asking how much to spend, ask how much a sale can fund. A campaign generating sales can lose money. One generating forms can cost more once sales time is included.
The foundation to read before launching on any platform.
- NeedA person to help
- AdA verifiable promise
- PageA consistent answer
- ActionMeasurable success
- ContributionEconomics that work
Build an economic threshold
Use revenue comparable with costs: for example excluding tax when VAT is remitted. Subtract variable delivery costs, service time, commissions, payments, discounts and a realistic return allowance. Do not treat future renewals as certain.
Fictional example: €120 revenue net of tax, €40 variable costs, leaving €80 contribution before advertising. To preserve €20 per sale, €60 remains for media only if other acquisition costs are already allowed for. At €80 media CPA, you break even before fixed costs; that is not profit.
Maximum CPA ≠ target CPA
The economic ceiling is a limit. Choose a more cautious target and reserve room for variation, management and creative. A target CPA bid does not guarantee actual cost.
A lead represents a probability of sale
If 20% of leads become customers and target media CPA is €60, indicative target CPL is €12. Measure this rate on complete cohorts; five inquiries cannot establish a constant.
Fund a specific question
Write your hypothesis: “This demonstration can generate qualified inquiries below my target CPL.” Define the offer, geography, tracking and overall ceiling. Reserve part of the budget for a page correction or creative variant; do not spend everything on media.
Illustration, not a universal recommendation: €300 media at a €60 CPA target implies five expected acquisitions if the target is achieved. This is still a small sample and may produce zero sales. A budget unable to cover your sales cycle may be too small to answer the question; validate the offer another way first.
Ceiling and pacing
Record total spend, period, billing settings and alerts. Average daily budgets can vary by system. On Google, the daily limit is generally twice the average budget and the monthly limit 30.4 times, with exceptions and adjustments: check your campaign rules.
Section sources : Google: spending limits
Decide without a magic rule
Before launch, define immediate stop conditions: broken payment, wrong country, incorrectly counted event, rejected offer or reached spending limit. To judge performance, wait for mature conversions and examine uncertainty. “Stop after 24 hours” does not fit every sales cycle.
Profitable in the dashboard, fragile in reality
A campaign can capture customers who would have purchased without ads. Compare new customers, overall contribution and, when volume permits, a control area or group. Attribution estimates a link; incrementality seeks a causal effect.
Calculate my threshold
Calculate my threshold
Calculate in the currency of your costs. These thresholds assume one sale, comparable revenue and complete variable costs. Creative, management, tools and fixed costs must be funded separately or allowed for in costs. Future rates are hypotheses.
- Contribution before ads
- 80 €
- Maximum media CPA at break-even
- 80 €
- Indicative target media CPA
- 60 €
- Indicative target CPL
- 12 €
- Media break-even ROAS
- 1,50
- ROAS required for the target
- 2,00
Indicative thresholds calculated. Compare them with actual results and other costs before deciding.
The launch plan
The launch plan
List costs
Separate variable costs per sale and fixed test costs. Include creative, management and qualification time in your scope.
Calculate contribution
Use collected revenue after discounts and expected refunds, with a consistent tax basis.
Set target CPA and CPL
Preserve the contribution you need. For leads, use a cautious sale rate observed over the complete cycle.
Limit exposure
Set a media ceiling, review date, alerts and a person responsible for checking spend.
Reconcile records
Compare orders, unique customers, media invoices and test costs. Deduct refunds before the final decision.
Avoid
See mistakes before paying for them
Fictional examples. Corrections illustrate a method without guaranteeing an outcome.
Avoid
€300 media, €900 revenue, 25% contribution before ads: “It works!”
Why it blocks progress
Contribution is €225. After €300 media, it is −€75 before creative, management and fixed costs.
Build instead
At 25% contribution, media break-even ROAS is 4. Preserving profit and funding the rest requires a higher threshold.
What it changes
The target comes from offer economics, not a supposedly good ROAS for everyone.
Avoid
100 leads at €2, but only one sale: report CPL alone.
Why it blocks progress
Media CPA is €200. Time spent calling contacts increases fully loaded cost further.
Build instead
Compare a €10-per-lead campaign producing one sale in five: €50 media CPA before qualification.
What it changes
Sale rate and contribution determine the outcome. Both scenarios are fictional, not benchmarks.
Avoid
“They will pay for 12 months”, so any acquisition below twelve months of revenue seems acceptable.
Why it blocks progress
Churn, unpaid bills, service costs and cash payback can make that assumption dangerous.
Build instead
Base the initial threshold on collected contribution, then add cautious future value when cohorts demonstrate retention.
What it changes
Measured lifetime value, with payback compatible with your cash position.
Read these indicators together
- Contribution before ads
- Relevant net revenue − variable costs. Check omitted fees and returns.
- Media break-even ROAS
- 1 ÷ pre-ad contribution rate, excluding fixed and other acquisition costs. This threshold does not guarantee profit.
- Payback period
- Time required to recover acquisition costs using collected contribution. A good ratio is insufficient if cash arrives too late.
Put it into practice
You have €900 revenue, 25% contribution before advertising and €300 media.
Does ROAS 3 prove profit?
See the reasoning
No. 900 × 25% = €225 contribution before advertising. 225 − 300 = −€75 after media, before other costs. Media break-even ROAS is 1 ÷ 25% = 4.
Pre-launch checklist
Frequently asked questions
What minimum budget makes advertising profitable?
No budget guarantees profitability. Technical minima vary by system. A useful test budget depends on target CPA, sales cycle and the volume needed for a decision; it must remain affordable if lost.
Why is ROAS insufficient?
ROAS does not automatically deduct delivery costs, fees, refunds, creative, management and fixed costs. High revenue can leave negative contribution after advertising.
Official sources
Sources checked: 11 October 2026.
VIFLY editorial method. Examples and test plans are recommendations to adapt to your offer. Interfaces and rules can evolve.