How much budget do you need for online marketing? Plan backwards from your goal

Plan backwards from your goal: multiply your target number of enquiries by your expected cost per enquiry, then add management costs. That gives you a budget that matches your actual need, instead of a number borrowed from somewhere else. Start with a limited test budget over at least 90 days, measure your real cost per enquiry, and scale what measurably works.

In this article we show how the backwards calculation works in practice, with a worked example, what the difference is between media budget and management, which channels to fill in which order, and which KPIs actually matter.

#How do I calculate my online marketing budget backwards?

Most businesses start from a number that came from somewhere, "what the others spend on marketing", and are surprised when the results do not match. Better: start from the goal. You know how many additional enquiries per month you need and what an order is worth on average. From that, the budget follows.

#A worked example

Suppose a trade business in Dresden needs 10 additional qualified enquiries per month to fill its capacity. Cost per enquiry varies widely by industry and competition. We will use €50 as a working figure, a pure assumption that you should verify with your first test.

Two things about this example: every number is deliberately marked as an assumption. You only learn your real cost per enquiry once the channel has been running. And: €500 of media budget is a realistic starting point for a single channel, running two channels in parallel would scale the budget accordingly.

#What do I need to add on top of the ad budget?

The pure media costs, the ad spend you plan with Google or Meta, are only part of the budget. On top of that:

• Setup: tracking, pixels, conversion events, campaign structure. One-off, usually in the first month.
• Ongoing management: campaign fine-tuning, A/B tests, optimisation, reporting.
• Creative production: ad copy, images, occasionally video.

The digital marketing service from €890 per month plus ad spend includes setup and ongoing management. For planning, that means: calculate the media budget and management separately, but together in one plan. Plan for at least 90 days, below that, the numbers are usually too thin for reliable conclusions.

#Which channels in which order?

Not every industry needs the same channels, but a sensible order does exist, and the order matters because it concentrates your budget and improves measurability. If you spread your budget across three channels from day one, you end up with too little data on each channel for reliable conclusions.

The order:

1. Google Ads (search): your customers actively search for solutions, intent is highest here. The starting channel in most B2B and service contexts.
2. Meta Ads (Facebook & Instagram): reach and visibility, well suited for local audiences and industries with a visual pitch. Often the second channel.
3. SEO: in the long run often the cheapest channel per enquiry, but it takes time to show results. Worth it when you plan beyond 6 months.
4. Email / retargeting: reactivate existing contacts, follow up on enquiries. Cheap, but dependent on the data you already have.
5. LinkedIn / niche channels: only if your audience is actually there.

#Which KPIs actually matter?

"Likes", "reach", "impressions", the classic social media metrics feel good. But they say little about whether your budget actually brings new enquiries.

The KPIs that matter for budget steering:

• Enquiries per month: the primary goal. Everything else is a means to an end.
• Cost per enquiry: your steering metric. If it does not come down below the working figure over 90 days, the strategy needs adjusting.
• Return per euro (simplified ROI): orders × average order value ÷ total budget.
• Enquiry quality: how many of the enquiries actually turn into orders? A low cost per enquiry is of little use if the enquiries are not qualified.

Reach and engagement are not irrelevant, but they are metrics for evaluation, not for budget steering.

A common mistake: steering the budget by the wrong metrics. If you count likes every week, you optimise for image, not for revenue. It is better to review KPIs monthly. Over shorter periods, the numbers are too noisy for reliable decisions. What matters in the evaluation:

• When is the data sufficient? At least 90 days of campaign runtime before you can make a reliable statement about cost per enquiry.
• What is the difference between a click and an enquiry? A click is cheap; an enquiry costs. Between the two sit load time, form length and the relevance of the landing page.
• How do you measure quality? A simple rule: after 30 days, note for every enquiry whether it was qualified or not. After 90 days you have a number that tells you whether you are addressing the right audience.

#Checklist: planning your online marketing budget

• Target number of enquiries per month is set (from capacity or revenue planning)
• Average order value and expected margin contribution are known
• An assumed cost per enquiry is defined (and marked as an assumption)
• Media budget is calculated separately from management
• A test phase of at least 90 days is scheduled
• The primary channel is chosen (highest intent)
• Tracking and conversion events are set up before the campaign starts
• KPI targets are defined: enquiries per month and maximum cost per enquiry
• A buffer (e.g. 15 %) for the learning phase is included in the budget

#Conclusion: plan backwards, test within limits, scale with data

Your online marketing budget follows from your goal, not from an industry norm. The backwards calculation with target enquiries, expected cost per enquiry and management is the foundation. A test budget over at least 90 days gives you the data to decide on: what works measurably, what does not?

And if you are not sure whether your cost-per-enquiry assumptions are realistic: talk it through with us: we will run the numbers for you and show which channels make the most sense for your audience.