Claude Fable 5.1 vs Gemini 3.1 Pro (2026): Which AI Model Is Better?

Both are popular language models. Here is how Claude Fable 5.1 and Gemini 3.1 Pro stack up on price, strengths and weaknesses, and which one we would pick.

Claude Fable 5.1

Anthropic's Claude models (Fable 5.1, Opus 5.5, Sonnet 5, Haiku 4.5) with 1M-token context

9.0 /10

Pricing: Free plan, paid from $20/mo

Pros

1M-token context window on Fable 5.1, Opus 5.5 and Sonnet 5
Up to 128K output tokens per request, useful for long drafts and chapters
Opus 5.5 is billed at $4 / $20 per million tokens, well below Fable 5.1
Available on the Claude API, Amazon Bedrock, Google Cloud and Microsoft Foundry

Cons

Fable 5.1 costs $10 input / $50 output per million tokens
Free Claude plan only includes Sonnet and Haiku
No native image generation; text and image input only
Pro and Max users get only part of their weekly limits on Fable

Visit Claude Fable 5.1 ↗

Gemini 3.1 Pro

Google's Gemini models (3.1 Pro, 3.8 Flash) in the Gemini app, NotebookLM and the Gemini API

8.7 /10

Pricing: Free plan, paid from $4.99/mo

Pros

Gemini 3.8 Flash API price is $0.75 in / $3.75 out per million tokens until end of 2026
Free tier in the Gemini app and a free (rate-limited) API tier in AI Studio
Google AI Plus starts at $4.99 per month in the US
Same account unlocks Nano Banana images and Flow video

Cons

Gemini 3.5 Pro was announced in May 2026 but has not shipped; the Pro tier is still 3.1
Free API tier content may be used to improve Google's products
Gemini 3.8 Flash price doubles after 31 December 2026
Frequent Flash versions (3.5, 3.6, 3.7, 3.8 in four months) make pinning outputs harder

Visit Gemini 3.1 Pro ↗

Claude Fable 5.1 vs Gemini 3.1 Pro at a glance

	Claude Fable 5.1	Gemini 3.1 Pro
Editor score	9.0 / 10	8.7 / 10
Pricing model	Freemium	Freemium
Starting price	$20/mo	$4.99/mo
Reader upvotes	0	0
Best for	llm, anthropic, claude	llm, google, gemini
Makes	Blog posts & articles, Ad & marketing copy, Emails & newsletters, Scripts & outlines	Blog posts & articles, Ad & marketing copy, Emails & newsletters, Scripts & outlines
Maker	Anthropic	Google DeepMind
Latest release	2026-09	2026-02
Apps offering it	15	10

Our pick

Claude Fable 5.1 edges it with a score of 9.0 versus 8.7. Claude Fable 5.1 is the better fit if you value: 1m-token context window on fable 5.1, opus 5.5 and sonnet 5, up to 128k output tokens per request, useful for long drafts and chapters. Choose Gemini 3.1 Pro instead if you need: gemini 3.8 flash api price is $0.75 in / $3.75 out per million tokens until end of 2026, free tier in the gemini app and a free (rate-limited) api tier in ai studio.