GPT-5.1 Instant vs Grok-3
GPT-5.1 Instant and Grok-3 are closely matched at 36.7 and 30.4 on the LLM Stats Score. GPT-5.1 Instant is 1.7x cheaper per token.
OpenAI · xAI · Updated for 2026
Which is better?
GPT-5.1 Instant and Grok-3 are closely matched on the overall LLM Stats Score at 36.7 and 30.4.
In the 3 individual benchmarks reported for both models, GPT-5.1 Instant wins 3; this is a narrower head-to-head signal than the composite indexes.
On price, GPT-5.1 Instant is roughly 1.7x 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
- you value its reported benchmark strengths — it wins 3 of 3 exact shared results
- cost matters — it's about 1.7x cheaper per token
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped Nov 2025
Choose Grok-3
- you want predictable pricing at $3.00/M input and $15.00/M output
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 · 5 for Grok-3
GPT-5.1 Instant outperforms in 3 benchmarks (AIME 2025, GPQA, MMMU), while Grok-3 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 2.4x cheaper than Grok-3 ($3.00/1M tokens).
For output processing, GPT-5.1 Instant ($10.00/1M tokens) is 1.5x cheaper than Grok-3 ($15.00/1M tokens).
In conclusion, Grok-3 is more expensive than GPT-5.1 Instant.*
* 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 Grok-3's 128,000 tokens. GPT-5.1 Instant can generate longer responses up to 128,000 tokens, while Grok-3 is limited to 8,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GPT-5.1 Instant and Grok-3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.1 Instant
Grok-3
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 Instant was released on 2025-11-12, while Grok-3 was released on 2025-02-17.
GPT-5.1 Instant is 9 months newer than Grok-3.
Nov 12, 2025
11 months ago
8mo newerFeb 17, 2025
1.6 years ago
Knowledge Cutoff
When training data ends
Grok-3 has a documented knowledge cutoff of 2024-11-17, while GPT-5.1 Instant's cutoff date is not specified.
We can confirm Grok-3's training data extends to 2024-11-17, but cannot make a direct comparison without GPT-5.1 Instant's cutoff date.
—
Nov 2024
Provider Availability
GPT-5.1 Instant is available from OpenAI. Grok-3 is available from xAI.
GPT-5.1 Instant
Grok-3
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.1 Instant and Grok-3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.1 Instant vs Grok-3.