Facebook ads cost calculator

The calculator chains three rates. Impressions are the budget divided by CPM, times 1,000. Clicks are impressions times the click-through rate. Results are clicks times your conversion rate. Cost per result is the budget divided by results, and ROAS is revenue (results times order value) divided by the budget.

Take the starting numbers: a 500 budget at a CPM of 10 buys 50,000 impressions. A 1% CTR gives 500 clicks, so 1.00 a click. A 3% conversion rate gives 15 results at about 33.33 each, and with a 50 order value that is 750 of revenue, a ROAS of 1.5. Those starting numbers are examples to show the mechanics, not benchmarks.

In the other direction, 20 sales at the same rates need 20 ÷ 3% = 667 clicks, which is 66,667 impressions at a 1% CTR, so a budget of about 667. The same chain in reverse always lands back on the forward answer.

The definitions follow the Marketing API insights reference on developers.facebook.com (docs/marketing-api/reference/ad-account/insights), read on 7 October 2026. It describes CPM as the average cost for 1,000 impressions, impressions as the number of times your ads were on screen, and CTR as the percentage of times people saw your ad and clicked. A separate link-click CTR counts only clicks on links. Spend is described as an estimated total.

Tip: There is no benchmark built in on purpose. CPM, CTR and conversion rate swing with audience, offer, creative and season, so a number from someone else’s campaign would mislead you. Use your own, or a small test campaign.

A ROAS of 1.5 sounds like profit, but only a share of each sale is left after the cost of the product. If you add a margin, the tool shows the break-even ROAS: one divided by the margin. At a 40% margin that is 2.5, so a ROAS of 1.5 loses money even though revenue exceeds spend.

• Results under 1 mean the budget may buy nothing: the tool flags it rather than showing a rounded zero.
• Rates are held constant. In a live campaign they can move as spend, audience or creative changes.
• It models one step from click to sale. A longer journey, such as a lead who buys weeks later, needs each step entered separately.
• It does not model delivery limits or learning phases, and Meta does not guarantee impressions.

If your ad sends people to Instagram or Messenger conversations instead of a web page, treat the conversion rate as clicks to the sales you close in the chat.