Free Ad Spend Forecaster
Model how scaling your ad budget impacts CPA and ROAS with diminishing returns.
Current Performance
How many times current spend to forecast
Forecast
Forecast uses a logarithmic diminishing returns model. Actual results vary by channel and market.
Forecasting Ad Spend: Understanding Diminishing Returns
Every paid channel has diminishing returns — as you increase spend, your CPA rises and ROAS declines. The question is not whether this happens, but at what rate. This forecaster uses a logarithmic model to project how your key metrics change as you scale from your current spend level to 2x, 3x, or beyond.
- Project how CPA and ROAS change at different spend levels
- Model diminishing returns before committing additional budget
- Identify the optimal spend level for your margin targets
- Make data-informed scaling decisions instead of guessing
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Ad Spend Forecaster FAQ
As you increase ad spend on a channel, each additional dollar becomes less efficient. Your CPA rises and ROAS drops because you exhaust the highest-intent audiences first and must reach less qualified prospects.
Stop scaling when your CPA exceeds your target threshold or when ROAS drops below profitability. This calculator helps you identify that inflection point before you overspend.
The logarithmic diminishing returns model is a reasonable approximation for most platforms (Google, LinkedIn, Meta). However, actual diminishing returns vary by channel, audience size, and creative quality.
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