OpenAI
GPT-5.4: price, context window, and caching
The March 2026 flagship that brought GPT-5.3-Codex's coding into OpenAI's main model, now positioned as the more affordable option.
Released March 5, 2026 · Prices as of September 28, 2026
In OpenAI’s words
“A more affordable model for coding and professional work.”
Facts
Specs and prices
| Fact | GPT-5.4 |
|---|---|
| Maker | OpenAI |
| API model id | gpt-5.4 |
| Released | March 5, 2026 |
| Status | Previous generation |
| Context window | 1.05M tokens |
| Max output | 128K tokens |
| Open weights | No |
| Input, per 1M tokens | $2.50 |
| Cache hit, per 1M | $0.25 |
| Cache write, per 1M | $2.50 (same as input) |
| Output, per 1M tokens | $15 |
| Runs in | Codex, Cursor, OpenCode, OpenRouter, and GitHub Copilot |
Standard API rates in US dollars, as published by the maker on September 28, 2026. Batch and priority tiers, taxes, and subscription plans are not included. GPT-5.4: Prompts over 272K input tokens cost 2x for input and 1.5x for output, for the full session.
Good to know
- Retired from Codex for ChatGPT sign-in on August 31, 2026, and still usable in Codex with an API key.
Cost
What typical work costs
Example token counts at GPT-5.4’s published rates. On the agentic session, caching saves $4.50 against billing every token as ordinary input.
| Agentic coding session, 100K input, 400K written to cache, 2M read from cache, 50K output | $2.50 |
|---|---|
| Large one-off review, 150K input with no cache hits, 10K output | $0.53 |
| Output-heavy generation, 30K input, 80K output | $1.28 |
| A month of sessions, 110 sessions: 5 a day, 22 working days | $275.00 |
Prompt caching
How OpenAI bills cached tokens
OpenAI
Prompt caching is on by default. From GPT-5.6 on you can also mark up to four explicit cache breakpoints, while GPT-5.5 and earlier cache automatically only.
From GPT-5.6 on, a cache write costs 1.25x the uncached input price and a cache hit costs 0.1x. GPT-5.5 and earlier add no charge for writing the cache: written tokens are billed as ordinary input, and a hit costs 0.1x on the models compared here.
On GPT-5.6 and later, a cached prefix stays reusable for at least 30 minutes after its last use, and caching starts at 1,024 input tokens.
Source: OpenAI: Prompt caching
GPT-5.4 compared
Claude Sonnet 4.6 vs GPT-5.4
Claude Sonnet 4.6 and GPT-5.4 both charge $15 per million output tokens, so the cost gap lives in cache writes. What that means for sessions and upgrades.
GPT-5.4 vs GPT-5.3-Codex
GPT-5.3-Codex is cheaper per token but takes 272K input tokens at most. GPT-5.4 reaches 1.05M, at higher rates past 272K. Which one fits your codebase.
GPT-5.5 vs GPT-5.4
GPT-5.5 costs exactly twice GPT-5.4 on every rate, and both are leaving Codex sign-in. What the 2x gap means for API users and where Codex points instead.
Your own numbers
See what GPT-5.4 really costs you.
everyaitoken reads your Codex, Cursor, OpenCode, and OpenRouter history on your Mac and prices every request at API rates, with what caching saved or cost. $9 once.