The four numbers that matter
Forget elaborate maturity models. Sizing tail-spend leakage only needs four inputs: annual indirect spend, headcount, the share of indirect that lives in the tail, and what tooling you currently run.
Get those four right and you can estimate annual leakage within 15% — enough to justify a real engagement.
- Annual indirect spend (AP-derived, last 12 months in USD)
- Headcount (loose proxy for transaction volume)
- % of indirect that is tail (default to 31% for US mid-market — our 2026 benchmark)
- Current tooling tier (email + sheets / basic P2P / unified platform)
The formula
We compare your current savings rate against the unified-platform ceiling we observe across customers. Email-and-spreadsheet teams average 4.2% savings on tail; basic P2P deployments average 7.3%; unified platforms average 11.4%.
The gap, applied to your tail spend, is your annual leakage.
- tailSpend = indirectSpend × tailPct
- leakagePct = unifiedRate (11.4%) − yourCurrentRate
- annualLeakage = tailSpend × leakagePct
Try it with your own numbers
The calculator below runs the same math live. Adjust the sliders and the monthly, annual and 3-year leakage update instantly. Nothing is sent anywhere — it all runs in your browser.
If the 3-year number makes you uncomfortable, that's the point. Book a free diagnostic and we'll validate the estimate against your actual AP ledger.