Cost Percent: The Share of Spend a Campaign Eats Up
Cost percent is a budget metric that shows how much of your total spend one campaign, keyword, or group consumes. This guide explains how to read it.
Cost percent is the share of total ad spend that a single campaign, keyword, or group consumes.
What Cost Percent Is
A cost percent is simply one line item divided by the total spend, expressed as a percentage.
It answers the question: where is the budget actually going?
Why It Matters
Spend can concentrate in a few keywords while most campaigns starve. Cost percent exposes that imbalance quickly.
It also reveals which terms are eating budget without producing results.
How to Use It
- Check which keywords claim the largest share of spend.
- Compare each keyword's cost percent with its revenue contribution.
- Shift budget from high-cost, low-return terms.
- Watch cost percent trends when raising or cutting bids.
How to Calculate It
- Divide the keyword or campaign cost by total spend.
- Multiply by 100 to get the percentage.
- Repeat across keywords to rank them by budget share.
- Use the ratio to guide monthly budget reviews.
The data: one keyword eats 40% of a monthly budget.
The check: it also delivers only 8% of conversions.
The move: the team trims its bid and reallocates to cheaper, converting terms.
The lesson: a big share of spend is only fine when it earns a big share of results.
Quick Tip
Review cost percent alongside conversions, not alone, so you cut waste without cutting winners.
Frequently Asked Questions
Cost Percent, Bottom Line
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