What counts as ad spend
Ad spend is the media cost of advertising: what you pay Meta, Google, TikTok, Apple Ads, ad networks, affiliates and influencers to deliver your campaigns. It excludes the cost of the people and tools that run them. Keeping that line clear makes metrics comparable over time; fully loaded costs belong in CAC and ROI, not in ROAS.
Ad spend in core metrics
Spend is the cost input to almost every UA metric. A worked example for one month:
- Spend: $50,000
- Attributed installs: 25,000, so CPI is $2.00
- Purchasers: 1,000, so cost per purchaser is $50
- D30 revenue: $45,000, so D30 ROAS is 0.9x
If D90 revenue reaches $75,000, D90 ROAS is 1.5x. The same spend looks different at each horizon, which is why ROAS targets always need a day attached.
Planning and allocating spend
- Start from value. A user worth $12 at your payback horizon sets the ceiling on CPI.
- Watch marginal returns. The next $1,000 on a channel matters more than the average. If doubling spend lifts installs by only 40%, marginal CPI has risen sharply.
- Diversify carefully. Test new channels with small budgets and scale what holds ROAS.
- Plan for seasonality. Media gets more expensive in the fourth quarter and festival periods.
- Reallocate weekly. Move budget from campaigns below target to those above it, using consistent attribution.
Tracking spend accurately
Spend from network dashboards is easy to collect but hard to compare, because each network attributes conversions its own way. The fix is to bring spend into the same system that attributes installs and revenue. Linkrunner syncs spend from Meta, Google Ads and Apple Ads and reports CPI, cost per event and ROAS down to ad set, creative and keyword. For quick planning, use the ROAS calculator or compare against cost per install benchmarks.