Ad Budget Calculator — How Much to Spend on PPC Ads
Work backwards from a sales goal to the ad budget you need: orders, clicks, monthly and daily budget, CPA, expected ROAS and profit after ad spend for Google, Meta or any pay-per-click campaign.
How it works
Orders = revenue goal ÷ average order value · Clicks = orders ÷ conversion rate · Monthly budget = clicks × CPC · Daily budget = monthly ÷ 30.4 · CPA = budget ÷ orders = CPC ÷ conversion rate · ROAS = revenue ÷ budget · Break-even ROAS = 1 ÷ gross margin · Profit after ads = revenue × margin − budget
Instead of guessing a budget, start from the result you want. Every order needs a number of clicks set by your conversion rate, and each click costs your average CPC, so the budget follows directly. Google Ads uses 30.4 as the average days per month when it turns a daily budget into a monthly limit. The campaign is profitable when ROAS beats the break-even ROAS of 1 ÷ gross margin; use your own historical CPC and conversion rate for the most realistic plan.
Worked example
To make $20,000 a month at an $80 average order you need 250 orders. At a 3% conversion rate that is 8,333 clicks, and at $0.80 per click the monthly ad budget is $6,666.67 — about $219.30 per day. Each order costs $26.67, ROAS is 3.00× against a break-even of 2.50× (40% margin), leaving $1,333.33 of gross profit after ads.
Sources: Google Ads Help — About average daily budgets (30.4 days) · Google Ads Help — Cost per click (CPC)
Frequently asked questions
How do I calculate my advertising budget?
Divide your revenue goal by the average order value to get orders, divide orders by your conversion rate to get clicks, and multiply clicks by your average cost per click. $20,000 ÷ $80 = 250 orders ÷ 3% = 8,333 clicks × $0.80 = $6,667.
How do I set a daily budget?
Divide the monthly budget by 30.4, the average number of days in a month that Google Ads uses. A $6,667 monthly budget is about $219 per day.
What is a good ROAS for my ad budget?
Any ROAS above 1 ÷ gross margin is profitable before fixed costs. At a 40% margin you break even at 2.5× and a 3× ROAS leaves profit; at a 25% margin you need at least 4×.
What percentage of revenue should go to advertising?
Many small businesses spend roughly 5–10% of revenue on marketing overall, but a paid-ads budget should be set by unit economics: the CPA you can afford is the gross profit you make per order (or per customer over their lifetime).
Related calculators
Planning estimate only. Real results depend on your actual costs, prices, taxes and market — check the figures with your accountant or adviser before making business decisions.