How this calculator works
| Metric | Formula |
|---|---|
| Clicks needed | target leads ÷ conversion rate |
| Monthly budget | clicks × cost per click |
| Cost per lead (CPL) | budget ÷ leads |
| ROAS | (leads × close rate × revenue per customer) ÷ budget |
| Break-even ROAS | 1 ÷ gross margin |
| Maximum profitable CPC | conversion rate × close rate × revenue per customer × gross margin |
Worked example
With these inputs:
- Currency: USD ($)
- Target leads per month: 50
- Landing page conversion rate: 4%
- Average cost per click: 2.5
- Lead-to-customer close rate: 20%
- Average revenue per customer: 5,000
- Gross margin: 60%
Monthly ad budget: $3,125. 50 leads a month at a 4% conversion rate and $2.50 CPC needs about $3,125 a month in Google Ads spend.
| Clicks needed | 1,250 |
|---|---|
| Cost per lead | $62.50 |
| Daily budget | $103 |
| New customers per month | 10 |
| Customer acquisition cost | $313 |
| Revenue from ads | $50,000 |
| ROAS | 16x |
| Break-even ROAS | 1.67x |
| Gross profit after ad spend | $26,875 |
| Maximum profitable CPC | $24.00 |
Open this example in the calculator
How to set a Google Ads budget
- Start from the outcome: how many leads or sales do you need each month?
- Look up the cost per click for your main keywords and locations in Google Ads Keyword Planner.
- Use your website’s current conversion rate, or a conservative estimate if you have none yet.
- Calculate the budget, then check it against break-even ROAS before spending.
- Run for 4–6 weeks, replace the estimates with real numbers and re-plan.
ROAS vs break-even ROAS
ROAS (return on ad spend) is revenue divided by ad spend. A ROAS of 4x means every 1 spent brought in 4 of revenue.
Break-even ROAS is the point where gross profit exactly covers ad spend: 1 ÷ gross margin. With a 60% margin you break even at about 1.67x; with a 25% margin you need 4x. Comparing the two tells you whether to scale a campaign or fix it.
The levers that lower cost per lead
- Landing page conversion rate — doubling it halves the cost per lead at the same CPC.
- Keyword intent — terms like "hire", "cost" or "near me" convert better than broad research terms.
- Negative keywords — stop paying for searches that will never convert.
- Quality Score — relevant ads and fast pages lower the CPC you pay for the same position.
- Conversion tracking — feed real leads and sales back into Google Ads so bidding optimises for revenue, not clicks.
Open this calculator with your numbers
Every option can be set in the web address, so you can bookmark a scenario or send it to a colleague. AI assistants such as ChatGPT, Gemini, Claude and Perplexity can use the same parameters to open this calculator with your numbers and the result already on the page.
| Parameter | What it sets | Accepted values |
|---|---|---|
currency |
Currency | one of USD, INR, AED, GBP, EUR |
leads |
Target leads per month | number from 1 to 1000000, default 50 |
conversion_rate |
Landing page conversion rate | number from 0.1 to 100 (%), default 4 |
cpc |
Average cost per click | number from 0.01 to 100000 (in the chosen currency), default 2.5 |
close_rate |
Lead-to-customer close rate | number from 0 to 100 (%), default 20 |
deal_value |
Average revenue per customer | number from 0 to 1000000000 (in the chosen currency), default 5000 |
margin |
Gross margin | number from 1 to 100 (%), default 60 |
Also available as plain text for AI assistants and a free JSON API (OpenAPI spec).
Last reviewed by the Infikey Technologies team.
Disclaimer
This calculator is provided free for general information and planning only. Results are estimates based on the inputs you enter and the assumptions described on this page, reference data such as published prices may change, and actual costs and outcomes will differ. Nothing on this page is financial, legal, tax, investment or other professional advice. Infikey Technologies Private Limited, Infikey Technologies LLC and their directors, employees and affiliates make no warranty, express or implied, about the accuracy, completeness or suitability of this tool or its results, and accept no liability for any loss or damage, direct or indirect, arising from its use or from reliance on its results. Verify all figures independently and seek professional advice before making any decision. Use of this tool is at your own risk.