Impression discrepancy calculator
Two numbers in, one answer out: how many impressions were billed and never measured, what they cost, and where that sits against the thresholds the industry uses.
Pixtru guides · updated
The formula
discrepancy = (billed − measured) ÷ billed
cost of the gap = (billed − measured) × CPM ÷ 1,000
"Billed" is the count on the invoice, usually the DSP's. "Measured" is the count from the system you are checking it against: your ad server, or your verification vendor. Compare the same dates, in the same time zone, from finished reports.
The thresholds it checks
| Threshold | Where it comes from | What it means |
|---|---|---|
| 10% | The 4A's/IAB Standard Terms and Conditions | If the invoicing count is lower than the other by more than this over the invoice period, the parties reconcile. |
| 20% | Google's help pages for Campaign Manager 360 and Display & Video 360 | What Google calls a normal variance between its count and a third party's. |
Neither threshold says the impressions below it were delivered. See what gap is acceptable.
Once you have the number
A percentage says how much is missing, not where it went. The next step is to split it — by creative, site, browser and hour — and then to find the stage each impression stopped at: never served, never measured, not measurable, not viewable, or invalid. Why the numbers do not match walks through each, and when the tag never fires covers the largest.