GPT-5 Medium vs GPT-5.1 Instant
GPT-5.1 Instant has a slight edge in benchmark performance. GPT-5 Medium and GPT-5.1 Instant cost the same.
OpenAI · OpenAI · Updated for 2026
Which is better?
GPT-5 Medium outperforms in 0 benchmarks, while GPT-5.1 Instant is better at 1 benchmark (AIME 2025). GPT-5.1 Instant has a slight edge in benchmark performance.
Based on current benchmark, pricing, and model metadata for 2026.
Choose GPT-5 Medium
- you want predictable pricing at $1.25/M input and $10.00/M output
Choose GPT-5.1 Instant
- you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
- you want the most recent training data — it shipped Nov 2025
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5 Medium outperforms in 0 benchmarks, while GPT-5.1 Instant is better at 1 benchmark (AIME 2025).
GPT-5.1 Instant has a slight edge in benchmark performance.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5 Medium ($1.25/1M tokens) costs the same as GPT-5.1 Instant ($1.25/1M tokens).
For output processing, GPT-5 Medium ($10.00/1M tokens) costs the same as GPT-5.1 Instant ($10.00/1M tokens).
In conclusion, GPT-5 Medium and GPT-5.1 Instant cost the same.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 400,000 tokens. Both models can generate responses up to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5 Medium and GPT-5.1 Instant support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5 Medium
GPT-5.1 Instant
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 Medium was released on 2025-08-07, while GPT-5.1 Instant was released on 2025-11-12.
GPT-5.1 Instant is 3 months newer than GPT-5 Medium.
Aug 7, 2025
1.0 years ago
Nov 12, 2025
9 months ago
3mo newerKnowledge Cutoff
When training data ends
GPT-5 Medium has a documented knowledge cutoff of 2024-09-30, while GPT-5.1 Instant's cutoff date is not specified.
We can confirm GPT-5 Medium's training data extends to 2024-09-30, but cannot make a direct comparison without GPT-5.1 Instant's cutoff date.
Sep 2024
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Provider Availability
GPT-5 Medium is available from OpenAI. GPT-5.1 Instant is available from OpenAI.
GPT-5 Medium
GPT-5.1 Instant
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5 Medium and GPT-5.1 Instant side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5 Medium vs GPT-5.1 Instant.