GPT-5.1 Codex vs Particle-1
GPT-5.1 Codex and Particle-1 are closely matched at 29.2 and 32.0 on the LLM Stats Score. Particle-1 is 7.9x cheaper per token.
OpenAI · Particle AI · Updated for 2026
Which is better?
GPT-5.1 Codex and Particle-1 are closely matched on the overall LLM Stats Score at 29.2 and 32.0.
On price, Particle-1 is roughly 7.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Particle-1 also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5.1 Codex
- you want predictable pricing at $1.25/M input and $10.00/M output
Choose Particle-1
- cost matters — it's about 7.9x cheaper per token
- you process long inputs — it offers a 1,048,576 token context window
- you want the most recent training data — it shipped Oct 2026
At a glance
The differences that matter most.
Individual benchmarks
3 reported for GPT-5.1 Codex · 3 for Particle-1
GPT-5.1 Codex and Particle-1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.1 Codex ($1.25/1M tokens) is 5.0x more expensive than Particle-1 ($0.25/1M tokens).
For output processing, GPT-5.1 Codex ($10.00/1M tokens) is 10.0x more expensive than Particle-1 ($1.00/1M tokens).
In conclusion, GPT-5.1 Codex is more expensive than Particle-1.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Particle-1 accepts 1,048,576 input tokens compared to GPT-5.1 Codex's 400,000 tokens. Particle-1 can generate longer responses up to 131,072 tokens, while GPT-5.1 Codex is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GPT-5.1 Codex and Particle-1 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.1 Codex
Particle-1
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5.1 Codex was released on 2025-11-19, while Particle-1 was released on 2026-10-28.
Particle-1 is 11 months newer than GPT-5.1 Codex.
Nov 19, 2025
11 months ago
Oct 28, 2026
3 days ago
11mo newerKnowledge Cutoff
When training data ends
GPT-5.1 Codex has a documented knowledge cutoff of 2024-09-30, while Particle-1's cutoff date is not specified.
We can confirm GPT-5.1 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without Particle-1's cutoff date.
Sep 2024
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Provider Availability
GPT-5.1 Codex is available from OpenAI. Particle-1 is available from Particle AI.
GPT-5.1 Codex
Particle-1
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.1 Codex and Particle-1 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.1 Codex vs Particle-1.