---
title: Billing and Cost
description: Credits, usage, and how analysis is billed.
type: doc
icon: credit-card
sidebar:
  label: Billing and Cost
  order: 1
  icon: credit-card
search:
  tags: [platform]
---
Amplifier pricing is based on **audio tokens**. Charges are **flat per call** — audio duration does not affect cost. `GET /v2/account/credits` returns that balance: **1 credit = 1 token**.

## When charges apply

You are charged when analysis runs. Inconclusive results and quality flags still bill.

## Token rates

| API call | Tokens | With diarization |
|---|:---:|:---:|
| **Model API** (`/v2/models/{model_name}/analyze`) | 75 | 125 |
| **Sign API** (`/v2/signs/{sign_name}/analyze`) | 50 | 100 |

Diarization is a flat **+50 tokens** on the base rate ([Speaker diarization](/guides/audio-requirements#speaker-diarization)). Token price: **$0.002 per token** ($10 = 5,000 tokens).

## Example calculations

| Scenario | Tokens | Cost |
|---|---|---|
| `pulse` model bundle, no diarization | 75 | $0.15 |
| `stress` sign, no diarization | 50 | $0.10 |
| `pulse` model bundle + diarization | 125 | $0.25 |
| `stress` sign + diarization | 100 | $0.20 |

## Group and longitudinal calls

Each Longitudinal analyze endpoint bills like its non-group Model or Sign counterpart. Raw and longitudinal forms cost the same. Groups API lifecycle, membership, and trajectory/aggregate reads consume no credits. See [Longitudinal concepts](/guides/longitudinal#concepts).

## Credits

Read the remaining balance with `GET /v2/account/credits` — [Account API](/reference/account). Analyze endpoints return `402 Payment Required` when the balance is 0 — [Errors](/reference/errors).