Claude Fable 5.1 vs Gemini 3.1 Pro
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by Anthropic
|
by Google
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Sep 1, 2026 | Feb 19, 2026 |
| Pricing per million tokens | ||
| Input | $10.00/Mtok | $2.00/Mtok |
| Output | $50.00/Mtok | $12.00/Mtok |
| Blended avg | $20.00/Mtok | $4.50/Mtok |
| Cached input | $0.250/Mtok | $0.200/Mtok |
| Price basis | Cache hits and refreshes on Claude Fable 5.1 (and Claude Mythos 5.1) are priced at 0.025x the base input price — $0.25 per 1M tokens — where every other Claude model uses the standard 0.1x multiplier. Base $10/$50 per 1M tokens; Batch API $5/$25. Verified 2026-09-01 against platform.claude.com/docs/en/about-claude/pricing. | — |
| Specifications | ||
| Context window | 1M tokens | 2M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimageaudiovideo
|
| Benchmarks source: Vellum LLM Leaderboard | ||
| Avg benchmark score | 54.2 | 74.8 |
| Perf / dollar | 2.7 | 16.6 |
| Terminal-Bench 2.1 | 55.8 | 70.3 |
| OSWorld-Verified | 41.7 | 76.2 |
| Humanity's Last Exam | 65 | 44.4 |
| GPQA Diamond | — | 94.3 |
| MCP Atlas | — | 69.2 |
| BrowseComp | — | 85.9 |
| ARC-AGI 2 | — | 77.1 |
| HumanEval | — | 80.6 |
| AutoBench | 31.4 | — |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | 65.7 | 47.7 |
| AA Agentic Index | 61.3 | 23 |
| AA-Omniscience Index (−100–100) | 43.5 | 31.9 |
| GDPval-AA v2 | 1853 ELO | — |
| LMSYS Chatbot Arena | — | 1486.7 ELO |
| Providers | ||
| Available from |
Anthropic — $10.00/$50.00/Mtok
|
Google — $2.00/$12.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | Claude Fable 5.1 | Gemini 3.1 Pro | Savings |
|---|---|---|---|
| 1M tokens | $20 | $4.5 | $15.5 (77.5%) |
| 10M tokens | $200 | $45 | $155 (77.5%) |
| 100M tokens | $2000 | $450 | $1550 (77.5%) |
| 1000M tokens | $20000 | $4500 | $15500 (77.5%) |
When to pick which
distilled from the pricing and spec data above- your workload re-reads context (agents, RAG, long chats): cached input costs $0.250/Mtok — 98% off its list input price
- cost dominates: $4.50/Mtok blended vs $20.00 — 77.5% less on the same 50/50 token mix
- you need the longer context: 2M tokens vs 1M (2×)
- raw capability matters more than price: 74.8 vs 54.2 average benchmark score
The cheaper option here — Gemini 3.1 Pro costs $4.50/Mtok blended on Google.
Summary
Claude Fable 5.1 by Anthropic costs $10.00/Mtok input and $50.00/Mtok output, with a 1M-token context window. It supports text, image input.
Gemini 3.1 Pro by Google costs $2.00/Mtok input and $12.00/Mtok output, with a 2M-token context window. It supports text, image, audio, video input.
On a blended cost basis, Gemini 3.1 Pro is 77.5% cheaper than Claude Fable 5.1.It also has a larger context window.
On benchmarks, Gemini 3.1 Pro scores higher (74.8 vs 54.2) on average. In terms of value, Gemini 3.1 Pro has better performance per dollar (16.6 vs 2.7).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.