Ask most agency owners how the business is doing and they'll quote revenue. Ask an agency-finance specialist and they'll ask for Agency Gross Income first — because revenue includes money that was never really the agency's to keep.
The formula
AGI = Gross Billings − Pass-Through Costs
Pass-through costs are the media spend, freelancer fees, and third-party tools you bill the client for but don't actually earn a margin on. A $50,000/month retainer with $30,000 of ad spend passed through isn't a $50,000 engagement — it's a $20,000 one. Every profitability ratio that matters (utilisation, realization, delivery margin) should be calculated against that $20,000, not the $50,000.
Why this matters more in 2026
Agencies running media buying, paid social, or programmatic alongside creative or strategy work often have pass-through costs that dwarf their actual fee. Reporting against gross revenue in that setup doesn't just overstate the business — it makes hiring, pricing, and capacity decisions look safe when they aren't.
What to do with AGI once you have it
AGI is the denominator for the ratios that actually predict agency health: delivery margin (AGI minus direct delivery cost, divided by AGI — healthy agencies run 50-65%), and break-even AGI (fixed overhead plus target owner pay, divided by delivery margin %). Revenue can't answer either question honestly.
Run the free Agency Financial Health Check — it calculates your real AGI, utilisation, and margin numbers from six inputs, no email required. If you want to track this every month rather than as a one-off snapshot, the Agency Financial Operating System is a real 11-sheet spreadsheet built around exactly this formula.
