What is the difference between Claude Fable 5.1 and Gemini 3.5 Flash?

Claude Fable 5.1 is developed by Anthropic while Gemini 3.5 Flash is developed by Google AI. Claude Fable 5.1 has a 1.0M token context window vs Gemini 3.5 Flash's 1.0M. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

Which is better, Claude Fable 5.1 or Gemini 3.5 Flash?

It depends on your use case. Claude Fable 5.1 and Gemini 3.5 Flash each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 10 challenges so you can judge which fits your needs best.

How much does Claude Fable 5.1 cost compared to Gemini 3.5 Flash?

Claude Fable 5.1 costs $10/M input tokens and Gemini 3.5 Flash costs $1.5/M input tokens. Gemini 3.5 Flash is $8.50/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Fable 5.1 and Gemini 3.5 Flash on Rival?

This page shows a side-by-side comparison of Claude Fable 5.1 and Gemini 3.5 Flash across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Updated Sep 2026

Claude Fable 5.1vsGemini 3.5 Flash

Gemini 3.5 Flash is cheaper than Claude Fable 5.1 at $1.5/M vs $10/M input tokens.

Claude Fable 5.1 and Gemini 3.5 Flash compared across 10 shared prompts
Spec	Claude Fable 5.1	Gemini 3.5 Flash
Input price	$10/M tokens	$1.5/M tokens
Output price	$50/M tokens	$9/M tokens
Context window	1.0M tokens	1.0M tokens
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2026	May 2026

Our Verdict

Claude Fable 5.1

Gemini 3.5 FlashRunner-up

Not enough votes to call it. On the specs, Claude Fable 5.1 has the edge: bigger model tier, newer.

Gemini 3.5 Flash costs 5.6x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Fable 5.1

Input

$10.00

Output

$50.00

Gemini 3.5 Flash

Input

$1.50

6.7× cheaper

Output

$9.00

5.6× cheaper

Gemini 3.5 Flash is cheaper on both: 6.7× input, 5.6× output.

Where to run it

6 hosts, cheapest first

Claude Fable 5.14 hosts

HostInOutContextUptime

Amazon Bedrock$10.00 in$50.00 out1M—Anthropic$10.00 in$50.00 out1M99.1% up Azure AI Foundry$10.00 in$50.00 out1M99.1% up Google Vertex AI$10.00 in$50.00 out1M99.8% up

Gemini 3.5 Flash2 hosts

HostInOutContextUptime

Google Vertex AI$0.75 in$4.50 out1M76% up Google AI Studio$1.50 in$9.00 out1M99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Cost per 1M tokens

6 hosts, cheapest first

What we learned reading every model

Common questions

What is the difference between Claude Fable 5.1 and Gemini 3.5 Flash?

Which is better, Claude Fable 5.1 or Gemini 3.5 Flash?

How much does Claude Fable 5.1 cost compared to Gemini 3.5 Flash?

How can I compare Claude Fable 5.1 and Gemini 3.5 Flash on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages

Cost per 1M tokens

6 hosts, cheapest first

What we learned reading every model

Common questions

What is the difference between Claude Fable 5.1 and Gemini 3.5 Flash?

Which is better, Claude Fable 5.1 or Gemini 3.5 Flash?

How much does Claude Fable 5.1 cost compared to Gemini 3.5 Flash?

How can I compare Claude Fable 5.1 and Gemini 3.5 Flash on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages