Google Ads budget: how much should you spend per month?

Setting a Google Ads budget is guesswork for many B2B teams. You pick a round figure that feels safe, switch the campaign on and hope something comes out of it. That is exactly the wrong order. A budget is not a starting point, it is an outcome. You work it backwards from what you actually want: a certain number of customers per month. In this article we show how to get from your lead target, your cost per lead and your margin to a realistic monthly budget, and how to adjust that budget afterwards based on the numbers that genuinely matter for your pipeline.

This is part of the broader question of how paid search works. Read our pillar what is SEA first if you want to cover the basics of search advertising.

Start with your goal, not with an amount

The mistake almost everyone makes: the conversation starts with “we have 2,000 euros per month”. That figure comes from nowhere. It says nothing about how many customers you need, and therefore nothing about whether it is enough.

Turn the reasoning around. Start at the bottom of your pipeline and work upwards:

• How many new customers do you want per month from Google Ads?
• How many quotes or demos do you need to close those customers?
• How many leads do you need to get to those quotes?

Only once you have those numbers do you know how many leads your campaign has to deliver each month. That number is your starting point. If you want to do that calculation separately first, read how many leads do you need to sharpen your goal before you commit a single euro of budget.

The calculation: lead target times cost per lead

As soon as you know how many leads you need per month, you only need one more number: your cost per lead, or CPL. That is what you pay on average to bring in one enquiry through Google Ads.

Your CPL is built from two things you either see or estimate in your campaign:

• the average cost per click (CPC) for your keywords
• the percentage of visitors who actually fill in a form (your conversion rate)

A simple example to show the logic, not to serve as a benchmark: suppose a click costs you 4 euros and 1 in 25 visitors submits an enquiry. Then 25 clicks together cost 100 euros and deliver one lead. Your CPL in that case is 100 euros. If you need 20 leads per month, you land on a rough media budget of 2,000 euros.

That figure is not a promise, it is a guideline. Your real CPC and conversion rate depend on your industry, your keywords and the quality of your landing page. But the method stays the same: lead target times CPL gives you a first, evidence-based monthly budget instead of a finger-in-the-air number. If you would rather not calculate by hand, use our Google Ads budget calculator, which runs this chain for you. And if you want a substantiated forecast up front, building a budget forecast with Keyword Planner helps.

Test your budget against your margin

A budget that delivers enough leads is not automatically a good budget. The second test is your margin. Because if every customer costs you more to win than they bring in, you are buying losses.

So run the numbers all the way down to customer level:

• What does an average customer bring you in gross margin, not in revenue?
• How many leads do you need for one customer?
• So what is the maximum a customer may cost you to stay profitable?

Suppose a new customer brings you 1,500 euros in gross margin and you close one customer out of 10 leads. Then one customer costs you 10 times your CPL. At a CPL of 100 euros that is 1,000 euros in acquisition cost for a customer worth 1,500 euros in margin. That works. If your CPL rises to 200 euros, that same customer costs 2,000 euros and you lose money on every deal.

This test determines whether your budget should go up or down. If you have a lot of margin per customer and a long customer lifetime, you can bid more aggressively and spend more. If your margins are thin, you first need to improve your conversion rate or your targeting before you open up the budget. That is exactly why, when clients outsource Google Ads to us, we always start with the value of a customer and not with click volume.

Why a budget that is too small does not accelerate

Many teams commit a minimal budget “to test” and conclude after two weeks that Google Ads does not work. The problem often is not the channel, but the scale.

Google Ads optimises itself based on conversion data. With too little budget, the algorithm gets too few signals to learn who does and does not convert. You then pay for clicks during a period in which the system is still searching, and you pull the plug just before it could have delivered something. If you are starting with a limited budget anyway, read how to use Google Ads for small businesses smartly without crippling your learning phase.

A workable budget has to be big enough to collect enough conversions within a reasonable timeframe. Exactly how much that is depends on your CPL and your goals, but the rule is clear: count on a learning period and do not judge on one bad week. If you want to understand the numbers that really drive your budget, read Google Ads costs and how a bidding strategy spreads your budget across the searches that deliver the most.

Steer on pipeline, not on clicks

You now have a budget that is well founded: it follows from your lead target, your CPL and your margin. But the work only starts once the campaign is live. A budget is not a setting you choose once, it is a dial you adjust monthly based on real results.

The trap is that you start steering on the wrong numbers. Clicks, impressions and cost per click look busy in a dashboard, but they say nothing about whether your euros are turning into deals. A day with lots of cheap clicks feels like a win, while those clicks may not have produced a single enquiry.

So connect your campaign to what happens after the click. With offline conversion tracking and lead-to-deal attribution you see not only which clicks became a lead, but which leads actually became customers. Then you steer your budget towards the keywords and campaigns that build pipeline, and away from the searches that only push up your click counter. That is how paid search becomes the fast acquisition layer of your growth engine and not a cost item you feed on gut feel.

That is the difference between a budget you defend on your cost per click and a budget you defend on your revenue.

Ready to justify your budget?

You do not set a good Google Ads budget on gut feel, but by working backwards from your lead target, your cost per lead and your margin per customer. If you are investing in SEO alongside ads, weigh up how you split your SEO and SEA budget across both channels. Want to get that clear for your situation and tie your budget to deals instead of clicks? Get in touch and we will run the numbers with you.