What gets used first — my allowance or my prepaid balance?

Rolled-over allowance drains first, then this month's allowance, and your prepaid balance only if you've opted into overflow.

In order: any rolled-over allowance first (it’s the oldest and expires soonest), then this month’s allowance, and only then — if you’ve turned on pay-as-you-go overflow — your prepaid balance, up to the overflow cap you set. AI answers never touch your balance unless you opt in.

The one thing billed to the prepaid balance directly is usage-based GitHub Automations compute: it never draws on the allowance, in any overflow mode.