Claude Fable 5.1 vs Gemini 3.8 Flash
Claude Fable 5.1 and Gemini 3.8 Flash are closely matched at 56.9 and 51.8 on the LLM Stats Score. Gemini 3.8 Flash is 13.3x cheaper per token.
Anthropic · Google · Updated for 2026
Which is better?
Claude Fable 5.1 and Gemini 3.8 Flash are closely matched on the overall LLM Stats Score at 56.9 and 51.8.
In the 3 individual benchmarks reported for both models, Claude Fable 5.1 wins 3; this is a narrower head-to-head signal than the composite indexes.
On price, Gemini 3.8 Flash is roughly 13.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Gemini 3.8 Flash 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 Claude Fable 5.1
- your work emphasizes reasoning — it leads those capability indexes
- you value its reported benchmark strengths — it wins 3 of 3 exact shared results
Choose Gemini 3.8 Flash
- cost matters — it's about 13.3x 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 Sep 2026
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 · 13 for Gemini 3.8 Flash
Claude Fable 5.1 outperforms in 3 benchmarks (GDPval-AA, OSWorld 2.0, Terminal-Bench 4.0), while Gemini 3.8 Flash is better at 0 benchmarks.
Claude Fable 5.1 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, Claude Fable 5.1 ($10.00/1M tokens) is 13.3x more expensive than Gemini 3.8 Flash ($0.75/1M tokens).
For output processing, Claude Fable 5.1 ($50.00/1M tokens) is 13.3x more expensive than Gemini 3.8 Flash ($3.75/1M tokens).
In conclusion, Claude Fable 5.1 is more expensive than Gemini 3.8 Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Gemini 3.8 Flash accepts 1,048,576 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 Gemini 3.8 Flash is limited to 65,536 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Fable 5.1 and Gemini 3.8 Flash support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Fable 5.1
Gemini 3.8 Flash
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 Gemini 3.8 Flash was released on 2026-09-02.
Gemini 3.8 Flash is 0 month newer than Claude Fable 5.1.
Sep 1, 2026
1 days ago
Sep 2, 2026
0 days ago
1d newerKnowledge Cutoff
When training data ends
Gemini 3.8 Flash has a documented knowledge cutoff of 2026-03-31, while Claude Fable 5.1's cutoff date is not specified.
We can confirm Gemini 3.8 Flash's training data extends to 2026-03-31, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.
—
Mar 2026
Provider Availability
Claude Fable 5.1 is available from Anthropic. Gemini 3.8 Flash is available from Google.
Claude Fable 5.1
Gemini 3.8 Flash
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Fable 5.1 and Gemini 3.8 Flash side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Fable 5.1 vs Gemini 3.8 Flash.