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Head-to-head comparison

Claude Fable 5.1 vs Gemini 3.5 Flash Lite

Claude Fable 5.1 (Anthropic) and Gemini 3.5 Flash Lite (Google) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 22 October 2026

As of 22 October 2026, Claude Fable 5.1 holds the stronger ModelCap Index position (#3 vs #33); and Gemini 3.5 Flash Lite is 20× cheaper per output token ($2.50/1M vs $50.00/1M).

Which should you choose?

Choose Claude Fable 5.1 if…

  • you want the stronger overall ModelCap Index position — #3 against #33 (85.9 vs 71.8 points).
  • you want provider choice — 4 listed API providers against 2.
  • Arena text is your yardstick — 1503 against 1455.
  • Arena coding is your yardstick — 1539 against 1502.
  • ARC-AGI-2 is your yardstick — 90.0% against 10.3%.
  • AA Intelligence Index is your yardstick — 53.4 against 22.2.
  • AA Terminal-Bench 2.1 is your yardstick — 91.4% against 53.6%.
  • AA Humanity's Last Exam is your yardstick — 59.1% against 18.8%.
  • you want the more recently listed model — Claude Fable 5.1 was listed 1 September 2026, Gemini 3.5 Flash Lite 21 July 2026.

Choose Gemini 3.5 Flash Lite if…

  • API cost matters — $2.50/1M output tokens against $50.00/1M, about 20× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.30/1M against $10.00/1M.

Claude Fable 5.1 vs Gemini 3.5 Flash Lite: specs, pricing and context

Specification comparison of Claude Fable 5.1 and Gemini 3.5 Flash Lite
FieldClaude Fable 5.1AnthropicGemini 3.5 Flash LiteGoogle
ModelCap Index position#3#33
Index score85.971.8
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$0.30
Output price / 1M tokens$50.00$2.50
Context window1M tokens1M tokens
Declared route output cap128K66K
API providers listed42
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, FileText, Image, Video, File, Audio
First listed1 September 202621 July 2026
PublisherAnthropicGoogle

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Fable 5.1 vs Gemini 3.5 Flash Lite

Public benchmark boards where Claude Fable 5.1 or Gemini 3.5 Flash Lite has a published result
BoardClaude Fable 5.1Gemini 3.5 Flash LiteLeads
Arena textArena (LMArena)15031497–1509Max14551451–1460Not reportedClaude Fable 5.1
Arena codingArena (LMArena)15391528–1550Max15021495–1509Claude Fable 5.1
LMArena AgentLMArena14.2%12.2%–16.1%Max—Only one result
ARC-AGI-2ARC Prize Foundation90.0%Max10.3%HighClaude Fable 5.1
AA Intelligence IndexArtificial Analysis53.4Reasoning22.2ReasoningClaude Fable 5.1
AA Terminal-Bench 2.1Artificial Analysis91.4%Reasoning53.6%ReasoningClaude Fable 5.1
AA Humanity's Last ExamArtificial Analysis59.1%Reasoning18.8%ReasoningClaude Fable 5.1
Terminal-Bench 4.0Terminal-Bench (Laude Institute)57.9%54.1%–61.6%Claude Code · Max—Only one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Fable 5.1 vs Gemini 3.5 Flash Lite: common questions

Is Claude Fable 5.1 better than Gemini 3.5 Flash Lite?

Claude Fable 5.1 ranks higher on the ModelCap Index as of 22 October 2026: #3 against #33. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is Claude Fable 5.1 cheaper than Gemini 3.5 Flash Lite?

Gemini 3.5 Flash Lite is cheaper on output tokens: $2.50/1M against $50.00/1M. Input tokens are $10.00/1M for Claude Fable 5.1 and $0.30/1M for Gemini 3.5 Flash Lite. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $45.00 for Claude Fable 5.1 versus $1.85 for Gemini 3.5 Flash Lite. Gemini 3.5 Flash Lite costs 95.9% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, Claude Fable 5.1 or Gemini 3.5 Flash Lite?

Both publish a 1M-token context window. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

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

Arena coding: Claude Fable 5.1 1539, Gemini 3.5 Flash Lite 1502 — Claude Fable 5.1 leads. AA Terminal-Bench 2.1: Claude Fable 5.1 91.4%, Gemini 3.5 Flash Lite 53.6% — Claude Fable 5.1 leads.

Are Claude Fable 5.1 and Gemini 3.5 Flash Lite open-weight models?

Claude Fable 5.1: No linked weights. Gemini 3.5 Flash Lite: No linked weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run Claude Fable 5.1 and Gemini 3.5 Flash Lite?

ModelCap currently lists 4 API providers for Claude Fable 5.1 and 2 for Gemini 3.5 Flash Lite, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Fable 5.1 vs Gemini 3.5 Flash Lite comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 22 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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