Facebook Ads budget calculator

Plan a Meta Ads budget backwards through the impression: conversions → clicks → impressions → spend.

Runs entirely in your browser — nothing is uploaded, nothing is stored. Updated 2026-09-30.

A Meta Ads budget is target conversions ÷ conversion rate ÷ click-through rate × CPM ÷ 1,000. 40 conversions at a 2.5% conversion rate, a 1.2% link CTR and an $11 CPM need 1,600 clicks, about 133,333 impressions and a budget of about $1,467 a month.

Meta sells impressions, so a Facebook Ads cost estimate has to run through them: a budget planned from cost per click alone ignores that the CPM and the CTR are the two numbers you actually influence — the audience sets one, the creative sets the other. The calculator runs the chain from the result you want to the spend it takes, and shows the implied cost per acquisition so you can check it against what your margin can pay before you launch.

Why a Meta budget is planned through the impression

Google Search is bought click by click, so the Google Ads budget calculator plans from cost per click. Meta's auction mostly prices the impression, and the cost per click you see afterwards is the CPM divided by the CTR. Planning from the CPC hides the two levers: a better creative raises CTR and cuts every downstream cost; a narrower audience raises CPM and raises them all.

Change one input at a time above and the effect is exact. At the seed numbers, lifting CTR from 1.2% to 1.5% cuts the budget from about $1,467 to about $1,173 for the same 40 conversions.

Budget for the learning phase, not only the target

Meta says an ad set usually exits the learning phase after about 50 results in the week after its last significant edit (About the learning phase). A plan for 40 conversions a month is roughly 9 a week, so an ad set optimised for purchases would stay in learning; optimising for a more frequent event, such as add to cart, or consolidating ad sets gives the system enough results to stabilise.

That is a planning constraint, not a detail: an ad set that never leaves learning keeps delivering less predictably, and the CPM and conversion rate you planned on will not hold.

Check the implied CPA first

The implied CPA is the plan's real test. If it is above what your margin allows — order value times gross margin, which the CPA calculator works out — no budget makes the plan viable; what changes it is conversion rate, CTR or order value.

Meta's own conversion counts include view-through conversions under default attribution settings and overlap with other platforms, so compare the plan against the conversions your store recorded, not only against Ads Manager.

Computing this from your own accounts

Every calculator on this page takes numbers you typed. The version that keeps working is the one that reads them from the accounts themselves — which is what TableBI is: connect Google Ads, Meta Ads, GA4 or Search Console once, and cpa() becomes a macro you can query from your terminal.

# connect once, then the metric is a standing query
tablebi connect google_ads
tablebi connect meta_ads   # beta: your own or test ad accounts

tablebi ask "WITH w AS (SELECT MAX(date) AS anchor FROM metrics)
   SELECT platform, cpa(SUM(cost), SUM(conversions)) AS cpa
   FROM metrics, w WHERE date > w.anchor - 30
   GROUP BY platform ORDER BY cpa DESC"

# pin the answer to a URL that refreshes itself
tablebi pin --title "Facebook Ads budget calculator by channel"
→ https://you.tablebi.com/d/dsh_…

The pinned answer is a live URL that refreshes on its own — here is one running now. No hosted model does the reasoning; your own Claude Code or Codex drives the CLI, which is why there is no inference bill attached to it.

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