GPT-5.1 Instant vs GPT OSS 120B
GPT-5.1 Instant leads the LLM Stats Score 36.7 to 29.2. GPT OSS 120B is 19.1x cheaper per token.
OpenAI · OpenAI · Updated for 2026
Which is better?
GPT-5.1 Instant leads the overall LLM Stats Score 36.7 to 29.2, ranking #70 overall.
In the 1 individual benchmarks reported for both models, GPT-5.1 Instant wins 1; this is a narrower head-to-head signal than the composite indexes.
On price, GPT OSS 120B is roughly 19.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.1 Instant also accepts a larger context window (400,000 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 Instant
- overall performance matters — it scores 36.7 and ranks #70 on LLM Stats
- your work emphasizes reasoning — it leads those capability indexes
- you value its reported benchmark strengths — it wins 1 of 1 exact shared results
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped Nov 2025
Choose GPT OSS 120B
- cost matters — it's about 19.1x cheaper per token
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
9 reported for GPT-5.1 Instant · 7 for GPT OSS 120B
GPT-5.1 Instant outperforms in 1 benchmarks (GPQA), while GPT OSS 120B is better at 0 benchmarks.
GPT-5.1 Instant significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.1 Instant ($1.25/1M tokens) is 13.9x more expensive than GPT OSS 120B ($0.09/1M tokens).
For output processing, GPT-5.1 Instant ($10.00/1M tokens) is 22.2x more expensive than GPT OSS 120B ($0.45/1M tokens).
In conclusion, GPT-5.1 Instant is more expensive than GPT OSS 120B.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.1 Instant accepts 400,000 input tokens compared to GPT OSS 120B's 131,072 tokens. GPT OSS 120B can generate longer responses up to 131,072 tokens, while GPT-5.1 Instant is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
GPT-5.1 Instant supports multimodal inputs, whereas GPT OSS 120B does not.
GPT-5.1 Instant can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-5.1 Instant
GPT OSS 120B
License
Usage and distribution terms
GPT-5.1 Instant is licensed under a proprietary license, while GPT OSS 120B uses Apache 2.0.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Apache 2.0
Open weights
Release Timeline
When each model was launched
GPT-5.1 Instant was released on 2025-11-12, while GPT OSS 120B was released on 2025-08-05.
GPT-5.1 Instant is 3 months newer than GPT OSS 120B.
Nov 12, 2025
9 months ago
3mo newerAug 5, 2025
1.1 years ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GPT-5.1 Instant is available from OpenAI. GPT OSS 120B is available from DeepInfra, Novita, OpenAI, Fireworks, Groq.
GPT-5.1 Instant
GPT OSS 120B
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.1 Instant and GPT OSS 120B side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.1 Instant vs GPT OSS 120B.