Advertising budget discussions often start with a sum: how much should we allocate to Google Ads or Meta Ads each month? But that figure alone does not tell you whether it is enough for your business goal or what customer acquisition cost your company can afford.
It is better to work backwards: establish an affordable customer acquisition cost, then estimate the number of leads and clicks required. After that, add agency or freelancer fees, content production, measurement setup and other expenses.
Let’s walk through a hypothetical example and identify what to check before launch.
What an advertising budget includes
For planning purposes, divide your costs into several categories.
Some costs arise at launch; others recur each month. Show them separately: analytics may not need to be set up again, while advertising materials may require regular updates.
Clarify whether the estimate includes taxes, fees, paid tools and content production. The amount described as the “advertising budget” should have a clear breakdown.
Establish an affordable customer acquisition cost first
Basing the calculation on order revenue alone is risky. That revenue also has to cover the product or service delivery, shipping and other costs associated with the sale.
For an initial estimate, use this approach:
Amount remaining from an order before acquisition costs = order revenue − variable costs of fulfilling the order.
The business still needs some of that amount for fixed costs and profit. You cannot allocate all of it to advertising if you expect a positive financial result from the first purchase.
Hypothetical example. A customer pays €800 for a service. Fulfilling the order costs €400. That leaves €400 before acquisition costs. The company decides to retain at least €100 towards fixed costs and its desired financial result.
The maximum total acquisition cost it can afford for this customer is therefore:
€800 − €400 − €100 = €300.
This is an internal planning limit for the example, not a recommended benchmark for every business. All amounts and conversion rates here and below are hypothetical: they are not agency prices, market averages or client results.
If you plan to recover acquisition costs through repeat purchases, use actual data on repeat orders, their profitability and timing. Expected future purchases do not replace the funds needed to pay for the launch now.
Calculate your budget backwards from sales to clicks
For advertising that brings visitors to a website, you can use this sequence:
Clicks → leads → new customers.
In this model, a lead is a genuine enquiry from a potential buyer. Repeat messages from the same person, spam and technical tests should not increase your count of new leads.
You need four inputs:
- How many new customers you want to acquire.
- What proportion of leads become customers.
- What proportion of advertising clicks generate a lead.
- The average cost per click.
The formulas are:
- Required leads = target number of customers ÷ lead-to-customer conversion rate.
- Required clicks = required leads ÷ click-to-lead conversion rate.
- Media budget = required clicks × average cost per click.
Use percentages as decimals: 20% is 0.20 and 5% is 0.05. Round fractional numbers of leads and clicks up.
Continuing our hypothetical example, the company wants 10 new customers. Assume that 20% of enquiries become customers, 5% of advertising clicks generate a lead and the average click costs €1.50.
- Leads: 10 ÷ 0.20 = 50.
- Clicks: 50 ÷ 0.05 = 1,000.
- Media spend: 1,000 × €1.50 = €1,500.
With these inputs, media spend would be €30 per lead and €150 per new customer. But that is not the full acquisition cost yet.
The calculation shows which conditions need to hold for you to reach the goal. It does not guarantee that an advertising platform will deliver enough clicks at your chosen price or that visitors will buy at the assumed conversion rate.
For leads generated through instant forms or messages, the journey is different. Start with the estimated cost per enquiry and the enquiry-to-customer conversion rate. For an online store without an enquiry stage, you can calculate the path directly from a click to a purchase.
Add service-provider fees and launch preparation
Let’s build a cost estimate for the same hypothetical example. Assume that all costs below relate to the chosen campaign and a comparable period, and that any additional charges are already included in the line items.
If the company actually acquires 10 new customers and spends €2,850, acquisition cost under this estimate would be €285 per customer.
That is within the chosen €300 limit, but leaves little headroom. If the entire contingency is also spent and the company acquires the same 10 customers, the figure rises to €315 and exceeds the limit.
The reserve does not automatically become an expense. It helps plan the funds you need available; include only the amount used in your actual customer acquisition cost.
Recalculate the estimate for the next period: one-off work may be complete, but new materials, improvements and lead-handling costs may arise. If your company has other acquisition costs, add them to the calculation.
Where to get cost-per-click and conversion estimates
The best starting point is your own data for a comparable product, market, source and period. Account separately for new and repeat enquiries, as well as changes to the offer and landing page.
If you do not have data yet, use preliminary estimates and clearly label them as assumptions. In Google Ads, Keyword Planner helps research searches and obtain performance forecasts under selected conditions. A forecast does not replace live campaign data or confirm future sales.
Do not copy cost-per-click and conversion figures from someone else’s case study without checking their relevance. A different market, language, product price or lead-handling process can substantially change the calculation.
For an international business, it helps to calculate budgets separately by market and language. Otherwise, an average may hide a segment that consumes budget but brings few suitable customers.
Check several scenarios
One figure creates a false sense of precision. Calculate what happens if conversion rates turn out lower or higher than expected.
Below are three hypothetical scenarios for a target of 10 new customers, all with the same €1.50 cost per click. Only conversion rates change.
This table does not estimate the likelihood of each scenario or show the full budget: team costs and preparation need to be added separately. Handling costs may also increase when you receive more leads.
If the cautious scenario is financially unacceptable, reconsider the goal or launch conditions. You could choose one product and market, improve the offer, limit the test or first check how enquiries are handled. Increasing the budget alone does not fix a weak conversion rate.
How to account for agency or freelancer fees
A specialist may charge a fixed fee, an hourly rate, a percentage of media spend or a combination of these. When comparing proposals, look at the scope and total cost at your planned budget.
Before starting, clarify:
- whether initial setup is charged separately from ongoing management;
- which channels, markets and campaigns are covered;
- whether copy, banners, video and their updates are included;
- who sets up analytics and lead delivery;
- whether website improvements are included;
- how additional tasks and costs are approved;
- what access and reports the client receives.
For percentage-based fees, clarify the amount used as the calculation base and whether a minimum fee applies. For hourly work, agree on an estimate, time tracking and what happens if the agreed scope is exceeded.
Show media spend and service-provider fees as separate line items. Also establish in advance who pays for media placement and who controls the advertising account, analytics and payment details.
How to launch within the agreed budget
Agree on the amount available to test the hypothesis, the evaluation period and the conditions for pausing. Do not spend the entire available reserve simply because the first few days produce few leads.
Before launch, check the enquiry journey: the form submits correctly, the lead reaches the team, its source is recorded and a responsible staff member can contact the person.
Check the advertising platform’s budget rules too. In Google Ads, for example, an average daily budget does not mean identical spending every day. For most campaigns, the daily spending limit can be twice the average daily budget, and the monthly limit is 30.4 times that budget when it remains unchanged throughout a full month. Additional conditions apply when you change budgets and for certain campaign types. See Google Ads’ spending-limit documentation.
If a sale takes several weeks, a lead generated this month may become a customer later. Compare the costs and results of the same group of acquired leads after allowing enough time for sales to conclude, rather than dividing this month’s spend by all this month’s sales from different sources.
Advertising reports also depend on the period during which a conversion is counted after an ad interaction. Google Ads explains this in its conversion-window documentation. Agree on measurement rules and reconcile results with actual enquiries and orders in your CRM.
Increase spending after checking lead quality, acquisition cost and the team’s capacity to handle a greater volume. Average acquisition cost may change as budgets grow, so update the model using new data.
A checklist before approving the budget
- The product, market and new-customer target are defined.
- Order fulfilment costs and an affordable acquisition cost are calculated.
- The sources of cost-per-click and conversion estimates are identified.
- Required leads, clicks and media spend are calculated.
- Service-provider fees, materials, measurement and lead handling are included.
- One-off costs, recurring costs and unused contingency are separated.
- Fees, paid tools and the estimate’s tax treatment are clarified.
- The cautious scenario and funds available before customer payments arrive are checked.
- Rules for spending, pausing and revising the budget are agreed.
- There is a defined method for connecting costs to suitable leads and new customers.
At iuntsevich.cz, you can discuss advertising setup and management based on your product, market and website readiness. The scope and terms of cooperation appear in our advertising commercial offer. Agree on media spend and any additional tasks before launch.
A useful budget calculation makes assumptions, costs and the conditions for affordable acquisition clear. After launch, replace assumptions with actual data and adjust the plan.