Target CPA Calculator

What is cost per acquisition?

Cost per acquisition (CPA) — also called cost per lead or cost per conversion — is the amount you pay in advertising to generate one new customer or lead. It is one of the most direct measures of ad efficiency: if your CPA is lower than what a customer is worth to you, your campaigns are working. If it is higher, you are paying to acquire customers at a loss.

The CPA formula is straightforward: total ad spend divided by the number of conversions in the same period. A $5,000 monthly ad budget that generates 50 leads has a CPA of $100. Whether that number is good or bad depends entirely on what those leads are worth to your business — which is what the calculator above is designed to tell you.

Cost per acquisition formula

The basic cost per acquisition formula is:

CPA = Total Ad Spend ÷ Total Conversions

That formula tells you what you did spend, not what you should spend. To set a target CPA that protects your margins, you need to work backward from your job value, delivery costs and profit goal — which is exactly what the calculator above does.

For service businesses, the more useful version of the formula accounts for your close rate. Not every lead becomes a customer, so you need to factor in how many leads it takes to close one job before you know what a lead is actually worth.

How to calculate cost per lead

Cost per lead is CPA applied at the top of the funnel — the amount you pay to generate an inquiry, form fill or phone call, before any sales process happens. The cost per lead formula is:

Cost per Lead = Total Ad Spend ÷ Total Leads Generated

The critical variable that connects cost per lead to profitability is your close rate. A $50 cost per lead sounds cheap, but if only 5% of leads convert to customers, your real cost per customer is $1,000. This calculator uses your close rate to show you the maximum you can pay per lead while still hitting your margin target — not just the maximum per customer.

What is a good average cost per lead?

Average cost per lead varies significantly by industry, market and how leads are defined. For local service businesses — HVAC, roofing, plumbing, home services — CPLs typically range from $30 to $150 depending on competition and geographic market. Higher-ticket services like legal, financial or healthcare can see CPLs of $100 to $500 or more.

The more useful benchmark is the number this calculator produces for your specific business. A higher-than-average CPL is still profitable if your job value and margins support it. A below-average CPL is still a problem if your margins are thin and your close rate is low.

What is price per lead?

Price per lead and cost per lead are often used interchangeably. In paid advertising contexts, cost per lead typically refers to what you actually paid. Price per lead may refer to what a lead generation service charges you upfront — a flat fee per inquiry regardless of whether that lead converts. The profitability math works the same way: multiply the price per lead by your close rate to find your true cost per customer, then compare that against your job value and delivery costs.

How to use a target CPA to set Google Ads budgets

Once you know your target CPA, you can work it into your Google Ads setup in two ways. The first is manually — if your target CPA is $80 per lead and you want 30 leads per month, your budget ceiling is $2,400 per month. The second is using Google’s Target CPA bidding strategy, which tells the algorithm what you want to pay per conversion and lets it optimize bids across auctions automatically.

Target CPA bidding works best when a campaign has at least 30–50 conversions in the past 30 days. Before that threshold, the algorithm does not have enough data to bid efficiently. You are often better off starting with Maximize Conversions and a manual budget cap, then switching to Target CPA once conversion data has accumulated.