Model Tracker
GPT-5.3-Codex
GPT-5.3-Codex is an AI model made by OpenAI. OpenAI released it on 5 February 2026. Its context window is 400,000 tokens.
GPT-5.3-Codex is an AI model made by OpenAI. OpenAI released it on 5 February 2026. Its context window is 400,000 tokens. Its longest answer is 128,000 tokens. Through the API it costs $1.75 per 1M tokens for input and $14.00 per 1M tokens for output. Its knowledge cutoff is 31 August 2025.
- Released
- 5 February 2026 — openai.com, read 19 October 2026
- Status
- Not confirmed: two readings disagree: deprecated and ga
- Takes
- Not confirmed: two readings disagree: text, image, code and text, code
- Returns
- Text, Code — openai.com, read 19 October 2026
- Open weights
- Not confirmed: The maker's pages reviewed do not state whether the model's weights are open or downloadable.
- Licence
- Not confirmed: The maker's pages reviewed do not name a licence for this model.
- Context window
- 400,000 tokens — developers.openai.com, read 19 October 2026
- Longest answer
- 128,000 tokens — developers.openai.com, read 19 October 2026
- Knowledge cutoff
- 31 August 2025 — developers.openai.com, read 19 October 2026
- API price, input
- $1.75 per 1M tokens — developers.openai.com, read 19 October 2026
- API price, output
- $14.00 per 1M tokens — developers.openai.com, read 19 October 2026
- Where
- API, Consumer app — openai.com, read 19 October 2026
- Parameters
- Not confirmed: The maker's pages reviewed do not publish a parameter count for this model.
- Model card
- Not confirmed: two readings disagree: https://deploymentsafety.openai.com/gpt-5-3-codex and https://openai.com/index/gpt-5-3-codex-system-card/
Benchmarks
Measured by others, not by the maker: each score with the name the measurer gives the model and the setting it ran, its day and its licence.
Epoch AI
- Epoch Capabilities Index, GPT-5.3 Codex: 156.8 (152.9–160.5), as of 19 October 2026
- SWE-bench Verified, gpt-5.3-codex_high: 74.8% (± 2.0), run 25 February 2026
Epoch AI, ‘Capabilities & benchmarking’, epoch.ai/benchmarks, CC BY 4.0: Epoch AI’s own runs and its Capabilities Index. Data · CC BY 4.0
Questions
When was GPT-5.3-Codex released?
OpenAI released GPT-5.3-Codex on 5 February 2026.
What is the context window of GPT-5.3-Codex?
The context window of GPT-5.3-Codex is 400,000 tokens, as OpenAI prints it.
How much does the GPT-5.3-Codex API cost?
On the standard tier, GPT-5.3-Codex costs $1.75 per 1M tokens for input and $14.00 per 1M tokens for output, as OpenAI lists it.
What is the knowledge cutoff of GPT-5.3-Codex?
The knowledge cutoff of GPT-5.3-Codex is 31 August 2025.
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Sources
- GPT-5.3-Codex Model (read 19 October 2026)
- Introducing GPT-5.3-Codex (read 19 October 2026)
- Deprecations (read 19 October 2026)
- Pricing (read 19 October 2026)
- GPT-5.3-Codex System Card (read 19 October 2026)