How can I check whether my Azure OpenAI GPT-5.4 or 5.6 bill is accurate?

Start with the detailed billing usage report, not just the total in Cost Analysis. Match the resource, deployment, region, model, meter, and UTC time window against Azure Metrics and your API usage logs. Compare input and output quantities separately before checking the prices.

One reported GPT-5.4 case had 2.777 billion billed input tokens versus 417.59 million in Azure Metrics over the same period. That is a substantial gap worth investigating, but it doesn't establish the cause. Check whether reporting delays or differences in what each source measures could explain any part of it, then ask support for a reconciliation of the remaining difference.

Check the meter names and rates as well as token counts. A quantity can look plausible and still produce a surprising bill if the billed rate differs from the published rate you expected. Compare the applicable region and model pricing with the detailed usage lines and the Retail Prices API.

Keep copies of the usage report, the rates you checked, and your calculation. That gives support something specific to investigate rather than just a large total.

For GPT-5.6, pay particular attention to cache charges. One report described a large cache write charge with no cache reads reported. The discussion also noted that GPT-5.6 usage responses do not report cache writes separately, so API logs alone may not let you verify that billed quantity.

Ask support to explain the cache write and read meters and how their quantities were calculated. Zero reported reads and high write charges are worth checking, but they aren't by themselves proof of a billing error.

Open a billing support case with the affected resource, dates, meter lines, and the differences you've calculated. Ask for a technical reconciliation and, if you've been overcharged, a correction or waiver. If the resource is managed through a partner, involve them too.

There are reports of cases taking weeks without a clear reconciliation, so keep the case numbers and updates together. The reports don't establish whether the discrepancies are widespread or intentional.

Don't wait for the invoice to check. Look at budget alerts and Cost Analysis during the billing period, especially after changing models. One reported switch from GPT-5.5 to GPT-5.6 was followed by a much higher daily charge, although that report doesn't explain the cause.