What the Target CPA & ROAS Calculator does
The Target CPA & ROAS Calculator works out the target cost per acquisition (CPA) or target return on ad spend (ROAS) to use in a Google Ads Smart Bidding strategy. It asks for three things, one at a time: what one sale is worth, your gross margin, and how much of the profit you’re willing to spend on ads. For lead generation it adds one more step that most people skip: how many leads actually become paying customers. It then shows your break-even number, your target, the picture of where one sale’s money goes, and exactly what to type into Google Ads.
How do I calculate a target CPA for lead generation?
Your target CPA is the gross profit from one customer, times the share of leads that become customers, times the share of that profit you’ll spend on ads. The Target CPA & ROAS Calculator uses these formulas:
gross profit per customer = average sale × gross marginbreak-even CPA = gross profit per customer × lead-to-customer ratetarget CPA = break-even CPA × share of profit spent on adsminimum daily budget = 3 × target CPA
Worked example: a plumbing company’s average job is $1,500 at a 50% gross margin, so one customer brings $750 of gross profit. Out of 100 leads, 16 become customers. Break-even CPA is $750 × 0.16 = $120: paying more than that for a lead loses money. Spending half the profit on ads gives a target CPA of $60, and a minimum daily budget of $180.
| Step | Formula | Result |
|---|---|---|
| Gross profit per customer | $1,500 × 50% | $750 |
| Break-even CPA | $750 × 16 in 100 leads | $120 |
| Target CPA | $120 × 50% spent on ads | $60 |
| Leads needed per customer | 100 ÷ 16 | 6.3 |
| Minimum daily budget | 3 × $60 | $180 |
Why do most people overestimate how many leads become customers?
Because they quote the share of sales conversations they win, not the share of leads. Google Ads counts every form fill and tracked call, including spam, sales pitches, job seekers, the wrong service, the wrong city, duplicates and people who never pick up. The Target CPA & ROAS Calculator first asks for a gut guess, then checks it in one of two ways: by counting the last 20–50 leads in your inbox, call log or CRM, or, if you don’t have records, by walking the leak one step at a time and multiplying.
In the plumbing example, 8 of every 10 leads are real people asking for plumbing in the service area, the company reaches 5 of every 10 real leads, and it wins 4 of every 10 people it talks to. The owner’s gut says 4 in 10 leads become customers. The math says 0.8 × 0.5 × 0.4 = 0.16, or 16 in 100. Using the gut number would put break-even CPA at $300 instead of $120, so the campaign would happily buy leads at $200 that lose $80 each.
If you count from records and have fewer than 20 leads, the Target CPA & ROAS Calculator warns you that one customer more or less moves the answer a lot.
How do I calculate a target ROAS for ecommerce?
Target ROAS is 1 ÷ (gross margin × share of gross profit spent on ads). Break-even ROAS is 1 ÷ gross margin. Google Ads asks for target ROAS as a percentage, so a ROAS of 5 is typed as 500%.
Worked example: an online store’s average order is $80 at a 40% gross margin, so each order brings $32 of gross profit. Break-even ROAS is 1 ÷ 0.40 = 2.5, or 250%. Spending half the gross profit on ads means paying $16 per order, which gives a target ROAS of $80 ÷ $16 = 5, typed into Google Ads as 500%.
Gross margin is not markup. A product you buy for $50 and sell for $100 has a 100% markup but a 50% margin. Count everything it costs to deliver an order: the product, shipping you pay, payment fees and returns. Don’t subtract rent, office salaries or ads; those come out of what you keep.
How much of my profit should go to Google Ads?
It’s your choice, and the Target CPA & ROAS Calculator offers it as a slider from 10% to 100% of gross profit with three marks:
| Mark | Share to ads | When it fits |
|---|---|---|
| Keep most | 30% | Tight cash or thin margins |
| Split it | 50% | A balanced place to start |
| Break even | 100% | Only if customers come back and buy again |
The share you keep pays for rent, salaries and your own profit. Spending 100% means the first sale earns nothing, which only makes sense when you know from your records that customers buy again.
How do I change my target in Google Ads without breaking the campaign?
Move the target 15% or less at a time, once a week, starting from what conversions cost now. Bigger jumps may restart the learning period, and a target CPA far below today’s cost per conversion can stop the campaign from showing at all. For a campaign that isn’t live yet, type the target from day one, because it is the guardrail on what you pay per lead.
Worked example: leads cost $90 over the last 30 days and the target is $60. The Target CPA & ROAS Calculator schedules $76.50 in week 1, $65.03 in week 2 and $60 in week 3. If today’s cost per lead is above break-even, it says so and links to the PPC Troubleshooter, because a lower target alone won’t fix a campaign that loses money on every lead.
Where to type it: open the campaign, then Settings → Bidding. For leads, choose Conversions, tick Set a target cost per action and enter the target CPA. For sales, choose Conversion value, tick Set a target return on ad spend and enter the target ROAS as a percentage.
Frequently asked questions
How do I calculate my target CPA for lead generation?
Multiply your average sale by your gross margin to get the gross profit from one customer. Multiply that by the share of leads that become customers to get your break-even CPA, the most one lead is worth. Then multiply by the share of that profit you are willing to spend on ads. A $1,500 job at 50% margin, with 16 of every 100 leads becoming customers, gives a break-even CPA of $120. Spending half of it gives a target CPA of $60.
How do I calculate target ROAS?
Break-even ROAS is 1 divided by your gross margin. Target ROAS is 1 divided by your gross margin times the share of gross profit you will spend on ads. At a 40% margin, break-even ROAS is 250%. Spending half of the gross profit on ads gives a target ROAS of 500%, which is what you type into Google Ads.
What close rate should I use for my target CPA?
Use the share of all leads Google Ads counted that became paying customers, counted from your own records, not the share of sales conversations you win. The leads Google counts include spam, wrong services, wrong areas, duplicates and people who never answer. A business that wins 4 of every 10 people it talks to may turn only 16 of every 100 leads into customers.
How fast should I change my target CPA in Google Ads?
Change it by 15% or less, once a week, starting from what conversions cost now. Bigger jumps may restart the learning period, and a target far below today's cost can stop the campaign from showing. If leads cost $90 today and your target is $60, type $76.50, then $65.03 the next week, then $60.
Related: set the campaign up with the Lead Gen Search Campaign Checklist, judge every keyword against your new target with Keyword Triage, and find out why a campaign isn’t hitting it with the PPC Troubleshooter.