# Volume pricing (https://docs.billwave.example/pricing/volume-pricing)

Volume pricing [#volume-pricing]

`volume` pricing uses the final tier reached to price **all** billable usage.

This is the model people often mean when they say "the more you use, the lower
your unit rate becomes."

Example [#example]

```ts
const agentRuns = metered("agent-runs", { name: "Agent Runs" });

plan("volume", {
  name: "Volume",
  price: 0,
  currency: "USD",
  interval: "monthly",
  features: [
    agentRuns.config({
      usageModel: "usage_based",
      reset: "monthly",
      ratingModel: "volume",
      tiers: [
        { upTo: 1000, unitPrice: 10 },
        { upTo: 10000, unitPrice: 7 },
        { upTo: null, unitPrice: 5 },
      ],
    }),
  ],
});
```

If usage is `1,500`, tier 2 is reached, so all `1,500` units are billed at `7`.

Mental model [#mental-model]

Ask:

* "What band did the customer end up in?"

That final band decides the rate for the full billable quantity.

Included + volume overage [#included--volume-overage]

Volume also works for included usage with chargeable overage:

```ts
agentRuns.limit(1000, {
  overage: "charge",
  ratingModel: "volume",
  tiers: [
    { upTo: 1000, unitPrice: 12 },
    { upTo: 10000, unitPrice: 9 },
    { upTo: null, unitPrice: 6 },
  ],
});
```

If total usage is `1,500`, only the `500` overage units are repriced by the
reached band.

Flat-fee bands [#flat-fee-bands]

Volume tiers can also be flat-only or mixed:

```ts
tiers: [
  { upTo: 100, flatFee: 5000 },
  { upTo: 1000, flatFee: 20000 },
  { upTo: null, flatFee: 50000 },
];
```

In a flat-only volume setup, the reached tier acts like a fixed-price band.

Use volume when [#use-volume-when]

* Entering a better band should reprice all billable usage
* Your pricing table is organized as reached bands
* You want lower effective rates at higher usage without accumulation logic

Compare with graduated [#compare-with-graduated]

See [Graduated pricing](/pricing/graduated-pricing) if you want each tier to
price only its own slice of usage.