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Claude Fable 5.1 vs Gemini 4 Hydrogen

Published LiveBench scores across all seven categories, live list pricing, context windows, and the measured cost of a point of capability — for both models, side by side.

OpenRouter + LiveBenchAll comparisonsFull leaderboard

Gemini 4 Hydrogen is the cheaper of the two; neither can be ranked on quality here.

Gemini 4 Hydrogen does not have a published LiveBench run, so this comparison covers price, context and declared capabilities only. A missing score means "not evaluated", not "worse" — the right way to separate these two is an eval on your own workload.

anthropic

Claude Fable 5.1

Blended / 1M
$20.00
Context
1M
Released
Sep 1, 2026
Overall score
84.0
reasoningtool callingimage inputfile inputprompt caching

google

Gemini 4 Hydrogen

Blended / 1M
$3.00
Context
1.0M
Released
Nov 12, 2026
Overall score
Not evaluated
reasoningtool callingaudio inputfile inputimage inputvideo inputprompt caching

Specs and pricing

MetricClaude Fable 5.1Gemini 4 Hydrogen
LiveBench overall

Weighted mean of the seven LiveBench category scores, 0–100. Higher is better.

84.0—
Cost per point

Measured benchmark spend divided by overall score — dollars per point of capability.

$0.0836—
Blended price / 1M

3:1 input:output mix, the usual shape of production traffic.

$20.00$3.00win
Input price / 1M$10.00$1.50win
Output price / 1M$50.00$7.50win
Cached input / 1M

Price of an input token served from the prompt cache, where the provider publishes one.

$0.250$0.075win
Context window1M1.0M
Max output tokens128K944Kwin

Benchmarks by category

An overall score averages away the thing you probably care about. These are the seven LiveBench categories scored separately — Claude Fable 5.1 on top, Gemini 4 Hydrogen below, both out of 100.

Long-horizon agentic
74.2
—
Coding
89.7
—
Reasoning
91.7
—
Browser
89.8
—
Data analysis
80.3
—
Research
88.5
—
Documents & design
81.6
—

What each one costs to run

Per-token prices are hard to feel. These are monthly list costs for both models across five workload shapes, using each provider's published cached-input rate where there is one.

WorkloadClaude Fable 5.1Gemini 4 Hydrogen
Support chatbot

1.2K in / 400 out × 200K requests

$5,698/mo$857.40/mo
RAG assistant

8K in / 600 out × 100K requests

$7,100/mo$1,080/mo
Coding agent

40K in / 4K out × 20K requests

$6,540/mo$1,002/mo
Document extraction

20K in / 1.5K out × 50K requests

$13,263/mo$1,991/mo
Bulk classification

500 in / 20 out × 5M requests

$25,125/mo$3,787/mo
Run these two through the cost calculator

Which should you pick?

You are cost-constrained

Gemini 4 Hydrogen

Cheaper on blended list price at $3.00 per million tokens.

Claude Fable 5.1 vs Gemini 4 Hydrogen FAQ

Which is better, Claude Fable 5.1 or Gemini 4 Hydrogen?

Gemini 4 Hydrogen is the cheaper of the two; neither can be ranked on quality here. Gemini 4 Hydrogen does not have a published LiveBench run, so this comparison covers price, context and declared capabilities only. A missing score means "not evaluated", not "worse" — the right way to separate these two is an eval on your own workload.

Is Claude Fable 5.1 cheaper than Gemini 4 Hydrogen?

Gemini 4 Hydrogen is cheaper. On a 3:1 input:output blend, Claude Fable 5.1 lists at $20.00 per million tokens and Gemini 4 Hydrogen at $3.00 — Gemini 4 Hydrogen is 6.7× cheaper. Input and output are priced separately — Claude Fable 5.1 charges $10.00 in and $50.00 out, Gemini 4 Hydrogen charges $1.50 and $7.50 — so the model that looks cheaper flips depending on how output-heavy your workload is.

Does Claude Fable 5.1 or Gemini 4 Hydrogen have a bigger context window?

They are effectively the same — 1M for Claude Fable 5.1 and 1.0M for Gemini 4 Hydrogen.

Do Claude Fable 5.1 and Gemini 4 Hydrogen support prompt caching?

Both publish a cached-input rate: $0.250 per million for Claude Fable 5.1 and $0.075 for Gemini 4 Hydrogen, against full input rates of $10.00 and $1.50. On a workload with a long stable prefix — a system prompt, a tool schema, a retrieved corpus — that changes the economics more than the headline price does.

Related comparisons

How these numbers are produced

  • Price — provider list price from OpenRouter, refreshed every 15 minutes. “Blended” is a 3:1 input:output mix.
  • Scores — LiveBench release 2026-11-06, using their own category map. Each model shows its strongest published run. A blank means “not evaluated”, never “bad”.
  • Cost per point — the measured dollars LiveBench spent on the run, divided by the score it earned.
  • “Win” — awarded only past a threshold: one full point on a benchmark score, 10% on a price, 25% on a context window. Anything tighter reports as a tie, because effort settings alone move a LiveBench score by more than that.

Published benchmarks rank models on someone else's tasks. Before committing, see LLM & agent evaluation for building an eval on your own.