Cost per lead is your ad spend divided by the number of leads it produced. Enter your own numbers below to also see your cost per sale and the most it makes sense for you to pay per lead before the sale stops being worth it.
By Ryan Richardson · Updated 7 October 2026
Divide total ad spend by the number of leads it produced: cost per lead = ad spend ÷ leads. Spend $2,000 on ads and get 40 leads, and your cost per lead is $50. That is the whole formula. Everything else on this page, cost per sale and break-even cost per lead, is the same division applied one step further down the funnel.
There is no number that is good on its own. A $50 cost per lead is cheap if the lead buys a $5,000 service and expensive if it buys a $50 product. What matters is your break-even cost per lead: average sale value, multiplied by gross margin, multiplied by close rate. Pay less than that and the lead is worth acquiring. Pay more and you are funding growth out of your own margin. Comparing your cost per lead to an industry average without knowing your own break-even number tells you very little, because the average hides exactly the three figures that decide whether a lead is cheap or expensive for your business.
Cost per lead is spend divided by leads. Cost per sale, sometimes called customer acquisition cost (CAC), is spend divided by the number of sales those leads produced. Cost per sale is always the higher number, because not every lead buys. In the worked example below, a $50 cost per lead becomes a $200 cost per sale once a 25% close rate is applied. Tracking cost per lead alone can hide a close-rate problem; tracking both numbers together shows whether a rising cost per lead is a rising cost per sale, or a cheaper lead that converts worse.
A cheaper lead that closes worse is not cheaper once you look at cost per sale; check that number before calling any change a win. Six things tend to move cost per lead, roughly in this order: the offer itself, who you are targeting, the page the lead lands on, the price and how it is framed, the proof you show, and how well you follow up afterwards. Most accounts have one of those six clearly holding the other five back. Send your numbers for a free teardown if you want a second opinion on which one is yours, or read the book for the full method behind each lever.
$2,000 of ad spend produces 40 leads, a 25% close rate, a $3,000 average sale and a 50% gross margin. Cost per lead is $2,000 ÷ 40 = $50. Cost per sale is $2,000 ÷ (40 × 25%) = $200. Break-even cost per lead is $3,000 × 50% × 25% = $375. At $50 a lead, there is $325 of room before the ads lose money.