Claude Fable 5.1 vs GPT-4.1 nano
Claude Fable 5.1 leads the LLM Stats Score 57.0 to 1.9. GPT-4.1 nano is 114.3x cheaper per token.
Anthropic · OpenAI · Updated for 2026
Which is better?
Claude Fable 5.1 leads the overall LLM Stats Score 57.0 to 1.9, ranking #1 overall.
On price, GPT-4.1 nano is roughly 114.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-4.1 nano also accepts a larger context window (1,047,576 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 Claude Fable 5.1
- overall performance matters — it scores 57.0 and ranks #1 on LLM Stats
- your work emphasizes reasoning and coding — it leads those capability indexes
- you want the most recent training data — it shipped Sep 2026
Choose GPT-4.1 nano
- cost matters — it's about 114.3x cheaper per token
- you process long inputs — it offers a 1,047,576 token context window
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
7 reported for Claude Fable 5.1 · 24 for GPT-4.1 nano
Claude Fable 5.1 and GPT-4.1 nanodon'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, Claude Fable 5.1 ($10.00/1M tokens) is 100.0x more expensive than GPT-4.1 nano ($0.10/1M tokens).
For output processing, Claude Fable 5.1 ($50.00/1M tokens) is 125.0x more expensive than GPT-4.1 nano ($0.40/1M tokens).
In conclusion, Claude Fable 5.1 is more expensive than GPT-4.1 nano.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-4.1 nano accepts 1,047,576 input tokens compared to Claude Fable 5.1's 1,000,000 tokens. Claude Fable 5.1 can generate longer responses up to 128,000 tokens, while GPT-4.1 nano is limited to 32,768 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Fable 5.1 and GPT-4.1 nano support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Fable 5.1
GPT-4.1 nano
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
Claude Fable 5.1 was released on 2026-09-01, while GPT-4.1 nano was released on 2025-04-14.
Claude Fable 5.1 is 17 months newer than GPT-4.1 nano.
Sep 1, 2026
1 days ago
1.4yr newerApr 14, 2025
1.4 years ago
Knowledge Cutoff
When training data ends
GPT-4.1 nano has a documented knowledge cutoff of 2024-05-31, while Claude Fable 5.1's cutoff date is not specified.
We can confirm GPT-4.1 nano's training data extends to 2024-05-31, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.
—
May 2024
Provider Availability
Claude Fable 5.1 is available from Anthropic. GPT-4.1 nano is available from OpenAI.
Claude Fable 5.1
GPT-4.1 nano
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Fable 5.1 and GPT-4.1 nano side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Fable 5.1 vs GPT-4.1 nano.