Ad budget calculator
Budgets set by gut feel are either wasted or starved. Enter the revenue you want from paid and your funnel numbers — get the budget the math actually requires, and whether it clears the learning floor.
How the budget is calculated
The calculator works the funnel backward. Revenue goal divided by average order value gives the orders you need. Orders divided by conversion rate gives the clicks you need. Clicks multiplied by CPC gives the budget — and from there, implied CPA and implied ROAS fall out for sanity-checking:
orders needed = revenue goal ÷ AOV
clicks needed = orders ÷ conversion rate %
budget = clicks × CPC
implied CPA = budget ÷ orders
implied ROAS = revenue goal ÷ budget
learning floor ≈ implied CPA × 30 conversions/monthA $50,000 monthly goal at a $95 AOV needs about 526 orders. At a 2.2% conversion rate that is roughly 23,900 clicks, and at a $1.40 CPC the budget lands around $33,500 — an implied CPA of about $64 and an implied ROAS near 1.5. Whether that plan makes money depends entirely on whether $64 is below your breakeven CPA.
The two checks most budget plans skip
First, profitability: implied CPA must sit below your breakeven CPA (contribution margin per order), or the plan converts ad spend into losses at scale. Run your numbers through the breakeven ROAS calculator and compare. Second, signal: automated bidding needs roughly 30 conversions per month per campaign to optimize. A budget that produces 12 conversions spread across five campaigns gives every campaign starvation-level data — consolidate until each surviving campaign clears the floor.
Budgets are outputs, not inputs
The most common budgeting mistake is treating spend as a fixed input — “we have $10k for ads” — and hoping revenue follows. Healthy accounts invert this: unit economics define the CPA you can afford, funnel math defines the volume available at that CPA, and the budget is whatever captures that volume. When performance holds at target, the budget should grow; when it slips below breakeven, no budget is the right budget until the funnel is fixed.
How much should I spend on ads per month?
Work backward from the revenue you want ads to generate: revenue goal ÷ AOV gives orders needed, orders ÷ conversion rate gives clicks needed, clicks × CPC gives budget. Then sanity-check two things — that the implied CPA is below your breakeven CPA (otherwise the plan loses money), and that the budget clears roughly 30 conversions per month so automated bidding has enough signal to optimize. There is no universal "right" percentage of revenue; the funnel math is the answer.
What is the minimum budget for Google Ads to work?
The practical floor is signal, not spend: Smart Bidding needs roughly 30 conversions per month per campaign to optimize reliably (Google recommends 30-day windows for tCPA strategies). Multiply your realistic CPA by 30 and that is your effective minimum for one properly structured campaign. Spending below the floor is not fatal, but expect slower learning, higher variance, and manual bidding often outperforming automation at that scale.
Why does the calculator warn about a learning floor?
Automated bidding learns from conversion volume. When a budget produces too few conversions per month, the algorithm cannot distinguish signal from noise — targets get missed, performance swings week to week, and the account underperforms what the same spend would do concentrated in fewer campaigns. If your required budget lands below the floor, the fix is usually consolidation: fewer campaigns, broader targeting per campaign, and one clear conversion goal.
Should the budget include all platforms or just one?
Run the calculation per platform, because AOV, conversion rate, and CPC differ meaningfully between Google Search, Shopping, Meta, and Microsoft Ads. A blended calculation hides the fact that one channel may need $8,000 to hit its share of the goal while another needs $20,000. Start from the channel with proven economics, fund it to its learning floor first, then expand.
My required budget is higher than I can afford. What now?
Lower the revenue goal or improve a funnel input — those are the only honest options. Raising conversion rate from 2% to 2.5% cuts the required budget by 20% at identical revenue; landing page and offer work is usually the cheapest budget reduction available. Cutting CPC through better Quality Score and query control helps too, but conversion rate is normally the bigger lever.
Want these numbers computed from your actual account?
The free audit reads your real data and shows where the economics leak — no generic benchmarks, no sales theater.