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Ad Budget Calculator

What a budget actually buys, step by step from spend to clicks to orders to revenue — using your numbers, not a benchmark.

✓ Recalculates as you type✓ The formula is printed on the page✓ Your figures never leave the tab

The plan

Cost per click and conversion rate should come from your own reporting, not from a published figure.

Budget currencyCost per click currency

Conversion rate%Average order value currency

Method

The arithmetic

The forecast is a chain of four multiplications, kept deliberately shallow so every step can be checked by hand. The budget buys clicks at your cost per click, a share of those clicks convert, each conversion is worth the average order value, and the resulting revenue over the budget is the ROAS. Cost per acquisition falls out of the same chain as budget over conversions.

clicks = budget ÷ CPC · conversions = clicks × CVR% · revenue = conversions × order value · ROAS = revenue ÷ budget · CPA = budget ÷ conversions

Worked example

One run through the numbers

A budget of 5,000 at a cost per click of 2.50 buys 2,000 clicks. At a 3% conversion rate that is 60 orders, and at an order value of 120 that is 7,200 of revenue — a ROAS of 1.44 and a cost per acquisition of 83.33.

Swap in your own figures — the result recalculates as you type.

Before you act on this

Where this number misleads

That worked example is not a success. A ROAS of 1.44 is below the 2.5 that a 40% gross margin requires, so on those assumptions the plan loses money before a single ad runs. A forecast that cannot show you a loss is not worth running — check the target against your break-even ROAS before committing the budget.
Every input should come from your own reporting. Cost per click and conversion rate vary so widely between markets, offers, and seasons that a figure borrowed from an article is closer to a guess than to data, and it will be the guess that decides the answer.
Cost per click is not fixed as budget grows. Increasing spend generally means bidding into less qualified inventory, so the real cost per click drifts up and the real conversion rate drifts down at exactly the moment the plan assumes both hold. Model the increase at more than one cost per click before believing the top line.
The chain assumes one order per conversion and no repeat purchase. Where customers come back, the first-order ROAS understates the campaign, and the honest version of the comparison is an acquisition-cost one rather than a revenue one.
Average order value hides its own distribution. If a handful of large orders pull the average up, the median customer is worth less than the forecast assumes, and the campaign needs the large orders to keep arriving at the same rate.

Asked often

Ad Budget Calculator: questions that come up

How much should I spend on ads?

This tool will not answer that, because the answer depends on figures only you have. What it does is turn a candidate budget into the clicks, orders, and revenue it implies, so you can see whether that revenue clears your break-even threshold before you commit rather than after.

Why is my real cost per acquisition higher than the forecast?

Usually because the conversion rate used was measured on a warmer audience than the ads will reach, or because the cost per click rose as budget increased. Re-run the forecast with the numbers the campaign actually produced in its first week rather than the ones it was planned with.

Should the budget include agency and creative costs?

Not in this chain — it models media only, which is what buys the clicks. Add those costs separately when comparing against break-even, because a plan that clears break-even on media alone can still lose money once production is counted.

Can I use this for impression-based buying?

Yes, but start a step earlier. Convert the CPM and click-through rate into a cost per click first with the CPM, CPC and CTR tool, then bring that figure back here.

Carry on

The next number

Run the numbers →