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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 3 September 2026

As of 3 September 2026, Claude Fable 5.1 holds the stronger ModelCap Index position (#2 vs #23); 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 — #2 against #23 (84.1 vs 66.2 points).
  • you want provider choice — 4 listed API providers against 2.
  • ARC-AGI-2 is your yardstick — 90.0% against 10.3%.
  • AA Intelligence Index is your yardstick — 65.7 against 37.4.
  • 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#2#23
Index score84.166.2
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$0.30
Output price / 1M tokens$50.00$2.50
Context window1M tokens1M tokens
Max output tokens128K66K
API providers listed42
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileText, Image, Video, File, Audio
First listed1 September 202621 July 2026
PublisherAnthropicGoogle

Evidence: 2 public benchmark observations across 2 boards · 5 public benchmark observations across 5 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 codingArena (LMArena)—15031495–1511Only one result
LMArena AgentLMArena—-10.8%-12.2%–-9.4%Only one result
ARC-AGI-2ARC Prize Foundation90.0%Max10.3%HighClaude Fable 5.1
AA Intelligence IndexArtificial Analysis65.7intelligence-index37.4intelligence-indexClaude Fable 5.1
AA Terminal-Bench 2.1Artificial Analysis91.4%terminal-bench-2.153.6%terminal-bench-2.1Claude Fable 5.1
AA Humanity's Last ExamArtificial Analysis59.1%humanitys-last-exam18.8%humanitys-last-examClaude Fable 5.1

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 3 September 2026: #2 against #23. 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.

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.

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

Both publish a 1M-token context window.

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

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: API only. Gemini 3.5 Flash Lite: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

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 comes from the sealed ModelCap dataset published 3 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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