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Claude Fable 5 vs GPT-5.4 Mini

Head to head on 25 shared benchmarks, with price, context window, and release dates.

Benchmark scores

45

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Model
Claude Fable 5

Anthropic

17.4%71.8%1933elo8356.3%92.6%55.5%63.5%81.4%78.6%80.0%59.9%88.5%93.9%87.3%68.9%95.0%51.9%60.2%76.9%62.9%66.0%74.2%90.4%98.5%83.9%38.6%90.0%--1340elo78.0%29.3%-29.8%1932elo66.0%-13.3%56.1%88.5%85.0%80.3%88.0%-69.4%
GPT-5.4 Mini

OpenAI

37.0%60.9%1662elo7345.4%60.6%5.9%38.8%70.9%71.6%70.9%60.3%71.5%78.6%72.5%63.5%21.0%50.8%39.6%71.2%18.2%39.6%54.2%48.0%23.4%---21.2%3.9%---28.3%---80.3%------61.748.4%
2 / 2 models
AttributeClaude Fable 5

Anthropic

GPT-5.4 Mini

OpenAI

DescriptionClaude Fable 5 is Anthropic's most capable widely released model, built for the most demanding reasoning and long-horizon agentic work. Shares its base model with the invitation-only Claude Mythos 5.GPT-5.4 mini is an AI model from OpenAI.
FamilyClaudeGPT
Params--
Open weightsclosedclosed
License-proprietary
Released9 Jun 202617 Mar 2026
Context1,000,000400,000
Input $/1M$10.00$0.75
Output $/1M$50.00$4.50
Cache read $/1M$1.000$0.075
Cache write $/1M$12.500-
Speed66 tok/s0 tok/s
Latency49.62 s0.00 s
Modalitiestext, image, filefile, image, text
Providers--
PublisherAnthropicOpenAI
Reported scores
IFBench63.5% (AA)
LiveBench - Math93.9% (LiveBench)
LiveBench - Coding78.6% (LiveBench)
GPQA Diamond60.6% (AA)
IFBench38.8% (AA)
SciCode39.6% (AA)

FAQ

Is Claude Fable 5 or GPT-5.4 Mini better?
Across the 25 benchmarks both models report on Sophon, Claude Fable 5 leads on 23 of them. Which one is "better" depends on the benchmark - the table above shows every shared score.
How do Claude Fable 5 and GPT-5.4 Mini compare on GPQA Diamond?
Claude Fable 5 scores 92.6% and GPT-5.4 Mini scores 60.6% on GPQA Diamond.
Which is cheaper, Claude Fable 5 or GPT-5.4 Mini?
GPT-5.4 Mini is cheaper at $4.50 per million output tokens against $50.00 for Claude Fable 5 - about 11.1x.
When were Claude Fable 5 and GPT-5.4 Mini released?
Claude Fable 5 was released 9 Jun 2026 by Anthropic. GPT-5.4 Mini was released 17 Mar 2026 by OpenAI.

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