Google Ads Budget Calculator
Work backwards from your sales target. See exactly how much you need to spend — and whether it'll be profitable.
Your Numbers
What You'll Need
How to work out your Google Ads budget
The biggest mistake businesses make is picking a budget out of thin air — "let's try £1,000 a month and see." A budget should be derived from a goal, not guessed. This calculator works backwards from the number of sales or leads you actually want, using only your own numbers — no made-up industry averages.
1. Clicks needed
To get a certain number of conversions, you need enough clicks to produce them at your conversion rate.
Want 50 sales at a 3% conversion rate? You need about 1,667 clicks a month.
2. Required budget
Multiply the clicks you need by what each click costs.
1,667 clicks at £1.50 CPC ≈ £2,500 per month. That's your starting budget to hit the target.
3. Will it be profitable?
Hitting a target isn't enough — it has to pay. The calculator checks your cost per acquisition against your break-even CPA.
Break-even CPA = AOV × Profit margin
Profit after ad spend = (Sales × AOV × Margin) − Budget
If your cost per sale is below break-even CPA, every sale is profitable before other costs. If it's above, you're paying more to acquire a customer than that customer earns you in gross profit — a signal to improve conversion rate or CPC before scaling.
Why your budget might be higher than you'd like
Two inputs do most of the damage: a low conversion rate and a high CPC. Both inflate the spend needed to hit the same target. The good news is both are improvable:
- Lift conversion rate with better landing pages — see our guide to high-converting ecommerce landing pages. Doubling conversion rate halves the budget needed for the same sales.
- Lower CPC by improving Quality Score and adding negative keywords — see why your CPC is high and how to lower it.
This is why optimisation often beats simply adding budget: a tighter account hits the same goal for less.
A note on the estimate
This is a planning model, not a guarantee. Real CPC and conversion rate vary by keyword, device, and season, and Smart Bidding needs a learning period before performance stabilises. Use the output as a starting budget and a profitability sense-check, then refine with real account data. For a wider view of what's realistic, read how much Google Ads should cost.
Related tools
Use the ROAS Calculator to pressure-test return and break-even, or the Ad Waste Calculator to see how much an existing account is leaking each month.
Frequently Asked Questions
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spent properly?
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