OpenAI Ultrafast vs Fast vs Standard: Which Should You Use?

Start with your product and plan. The Ultrafast controls described here belong to ChatGPT Work and Codex. OpenAI documents a separate API service tier for developers.

For an eligible ChatGPT account: open Work or Codex, select GPT-6 Astra, then choose Ultrafast in the model picker. Check your selected workspace when an expected option is missing.

OpenAI lists these default Astra Ultrafast token limits:

Treat these as capacity limits for the API. ChatGPT allowances follow separate rules.

The API supports global processing and US data residency. EU and other non-US regional processing endpoints are unsupported. Workspaces that require inference outside the US also lack access; the user's physical location alone does not decide eligibility.

For a planned API rollout, check the limits against your expected traffic before choosing a speed.

Some tasks spend much of their time generating an answer. Others wait for websites, file operations, or outside services. OpenAI's guidance treats model speed, output length, request count, and tool design as separate ways to reduce delays.

Here is a hypothetical example. A task takes 60 seconds: 40 seconds waiting on tools and 20 seconds generating text. If text generation becomes eight times faster, that part falls to 2.5 seconds. The full task still takes 42.5 seconds, assuming everything else stays unchanged.

OpenAI strongly recommends a persistent WebSocket connection for Ultrafast tasks with frequent tool calls. HTTP requests also work.

A WebSocket keeps the connection open across steps. OpenAI's WebSocket guide describes continuing with new input and the previous response ID. This reduces per-turn continuation overhead; a slow external tool still needs its own check.

This is guidance for your own API integration. In Work or Codex, choose an available speed through the product's controls.

Use the time to a correct, usable result when judging the upgrade.

OpenAI distinguishes included subscription allowance, purchased credits, and API charges. Your plan uses its included allowance first, then available credits for eligible usage.

For the same supported model, OpenAI lists these multipliers relative to Standard:

These figures describe usage and charges. They do not predict how much sooner a task will finish. Enterprise usage-based billing follows the workspace's agreement.

Under an equal-workload assumption, an allowance that covers 80 Standard runs would cover about 32 Fast runs or 10 Ultrafast runs. Real task sizes vary, so treat this as a ratio example rather than a promise about your plan.

Decision: Choose a faster mode when the time it saves justifies the extra usage. Keep Standard for work where you can wait.

For GPT-6 Astra, current short-context API text rates are shown below. Every price is in US dollars per million tokens, for prompts with up to 272,000 input tokens.

Keep the model fixed when comparing these rates. Cached input reuses saved prompt content; cache writes create that saved content. Longer prompts, tools, and regional processing can change the bill.

For an illustration with 20,000 ordinary uncached input tokens and 5,000 total billed output tokens, the token charges would be $0.45 on Standard, $0.90 on Fast, and $2.70 on Ultrafast. This calculation excludes cache-write fees, tools, and other charges.

API charges are separate from ChatGPT subscriptions. Codex with your own API key uses API pricing, so the ChatGPT allowance and purchased-credit multipliers above do not apply to that route.