How the forecast is calculated
Monthly budget = Daily budget × 30.4Clicks = Monthly budget / CPCConversions = Clicks × CVRRevenue = Conversions × Value of one conversionCPA = Budget / Conversions · ROAS = Revenue / Budget30.4 is the average number of days in a month: Google Ads treats the daily budget as an average and caps monthly spend at daily budget × 30.4 (Google Ads Help).
The pessimistic scenario uses the highest CPC and lowest conversion rate; the optimistic scenario the lowest CPC and highest conversion rate. Real results usually fall between the two, but this is not a guarantee.
Where to get the numbers
- CPC range: the low and high "Top of page bid" range for your keywords in Google Ads Keyword Planner. If you have an existing account, the actual CPC of the last 3 months is more reliable.
- Conversion rate: your site's GA4 or Google Ads data. Without data, start with a cautious low value and update after the first month.
- Conversion value: average order value or the average value of a lead (lead-to-sale rate × average deal).
Quality Score directly affects CPC: the more relevant your ad and landing page, the less you pay for the same position — see Quality Score.
Example
The numbers are hypothetical.
- Monthly budget 3,000, CPC 0.50–1.00, CVR 2–4%, order value 80, margin 30%.
- Pessimistic: 3,000 / 1.00 = 3,000 clicks → 60 conversions → 4,800 revenue, CPA 50, ROAS 1.6x.
- Optimistic: 3,000 / 0.50 = 6,000 clicks → 240 conversions → 19,200 revenue, CPA 12.50, ROAS 6.4x.
- Break-even ROAS = 1 / 0.3 ≈ 3.33x. The campaign loses money in the pessimistic case and makes money in the optimistic one — so the outcome depends on how well you manage CPC and conversion rate.
How to use the forecast
- If the pessimistic scenario gives very few conversions (a handful a month), Smart Bidding may not get enough data to learn — start with a narrower keyword set.
- If pessimistic ROAS is below break-even, improving the landing page and offer may pay off more than raising the budget.
- After the first 4–6 weeks, update the forecast with actual CPC and CVR.
- Budget allocation works differently in Performance Max — see running PMax without wasting budget.
Common mistakes
- Planning with a single CPC. Auction prices change daily; a range reflects reality better.
- Borrowing another industry's conversion rate. Insurance, e-commerce and B2B services are not comparable.
- Doubling the budget overnight. Extra clicks usually cost more as budget grows; CPC does not stay flat.
- Presenting the forecast as a promise. It is a planning tool; competition, seasonality and Quality Score change the outcome.
Frequently asked questions
How much budget do I need for Google Ads?
There is no universal amount. Work backwards from your target conversions: conversions needed / CVR = clicks needed; clicks × CPC = budget. This tool shows that calculation in pessimistic and optimistic scenarios.
How does a daily budget translate into monthly spend?
Google Ads caps monthly spend at the average daily budget × 30.4. Some days may spend more than the daily budget, but the monthly limit is not exceeded.
Where do I find CPC?
Google Ads Keyword Planner shows bid ranges per keyword. If your account is already running, recent actual CPC is the more accurate source.
How accurate is the forecast?
Only as accurate as the CPC and conversion rate you enter. Competition, seasonality, Quality Score and the landing page all affect real results, which is why the output is a range.
What if the pessimistic scenario shows a loss?
Raise the conversion rate (landing page, offer), lower CPC (Quality Score, more specific keywords) or start with higher-value products. You can also request a free audit of your account.
Are my numbers stored?
No. The calculation runs in your browser. The result is only sent to ClickOptimize if you submit the "Send the result to an expert" form.