Claude Fable 5.1 vs GPT-5.5
Wins 8 of 8 areas
Coding · Agents · Reasoning · Facts · Images and charts · Math · Long documents · Following instructions
Wins 0 of 8 areas
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Claude Fable 5.1 is the stronger all-rounder.GPT-5.5 is cheaper.
Both rank among the ten best models we track in reasoning, coding, agents, long documents and math.
Scores updated · 46 tests both models report · How we compare
Where each one wins
Tests won in each of the eight areas we test. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software60Claude Fable 5.16 of 6 tests
- ReasoningHard problems that need careful thinking50Claude Fable 5.15 of 6 tests · 1 tie
- AgentsCarrying out multi-step tasks on its own40Claude Fable 5.14 of 4 tests
- FactsGetting facts right instead of making them up30Claude Fable 5.13 of 3 tests
- MathCompetition and research-level math30Claude Fable 5.13 of 3 tests
- Images and chartsUnderstanding pictures, charts and video10Claude Fable 5.11 of 1 test
- Long documentsFinding answers in very long texts10Claude Fable 5.11 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Fable 5.11 of 1 test
Images and charts, long documents and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
GPT-5.5 costs 42% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Fable 5.1 pulls ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+37.4points ahead
- Long, multi-file coding tasks in real codebasesSWE-bench Pro+22.6points ahead
- Real work tasks from 44 professionsGDPVal+20.2points ahead
Where GPT-5.5 pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 46 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Fable 5.1
- LMArena · WebDevClaude Fable 5.1 by 254 rating points17411487+254 rating
- SWE-bench ProClaude Fable 5.1 by 22.681.258.6+22.6
- LiveBench · Agentic CodingClaude Fable 5.1 by 12.166.154+12.1
- SciCodeClaude Fable 5.1 by 7.363.155.8+7.3
- Terminal-Bench 2.1Claude Fable 5.1 by 7.191.484.3+7.1
- LiveBench · CodingClaude Fable 5.1 by 4.286.482.2+4.2
AgentsClaude Fable 5.1
- Terminal-Bench 4.0Claude Fable 5.1 by 37.45214.6+37.4
- GDPValClaude Fable 5.1 by 20.262.742.5+20.2
- τ-Bench V3 · BankingClaude Fable 5.1 by 8.247.239+8.2
- AA IT-Bench SREClaude Fable 5.1 by 3.749.545.8+3.7
ReasoningClaude Fable 5.1
- SimpleBenchClaude Fable 5.1 by 17.686.669+17.6
- Humanity's Last ExamClaude Fable 5.1 by 13.359.145.8+13.3
- ARC-AGI-2Claude Fable 5.1 by 59085+5
- CritPtClaude Fable 5.1 by 2.629.727.1+2.6
- LiveBench · ReasoningClaude Fable 5.1 by 291.789.7+2
- GPQA Diamondtie93.793.5tie
FactsClaude Fable 5.1
- AA-Omniscience · Non-hallucinationClaude Fable 5.1 by 16.427.411+16.4
- AA-Omniscience · AccuracyClaude Fable 5.1 by 9.267.258+9.2
- SimpleQA VerifiedClaude Fable 5.1 by 7.870.863+7.8
Images and chartsClaude Fable 5.1
- LMArena · VisionClaude Fable 5.1 by 26 rating points13181292+26 rating
MathClaude Fable 5.1
- FrontierMath Tier 4Claude Fable 5.1 by 15.387.872.5+15.3
- FrontierMath Tiers 1-3 (v2)Claude Fable 5.1 by 4.990.285.3+4.9
- LiveBench · MathematicsClaude Fable 5.1 by 1.19795.9+1.1
Following instructionsClaude Fable 5.1
- LiveBench · Instruction FollowingClaude Fable 5.1 by 2.37370.7+2.3
Other results21 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- GDP (Surge AI)Claude Fable 5.1 by 60.285.124.9+60.2
- GDPval-AA v2Claude Fable 5.1 by 344 rating points18531509+344 rating
- GDPval-AA v2 EloClaude Fable 5.1 by 344 rating points18351491+344 rating
- AA-OmniscienceClaude Fable 5.1 by 2343.520.5+23
- HiL-Bench (Tools-allowed)Claude Fable 5.1 by 21.861.539.7+21.8
- AA Agentic IndexClaude Fable 5.1 by 20.75837.3+20.7
- Program BenchClaude Fable 5.1 by 16.887.670.8+16.8
- AA IntelligenceClaude Fable 5.1 by 1553.438.4+15
- OfficeQA ProClaude Fable 5.1 by 14.96954.1+14.9
- HLE (with tools)Claude Fable 5.1 by 12.86552.2+12.8
- PostTrainBenchClaude Fable 5.1 by 11.840.228.4+11.8
- HealthBench ProfessionalClaude Fable 5.1 by 10.362.151.8+10.3
- HealthBench Professional length-adjustedClaude Fable 5.1 by 10.362.151.8+10.3
- Artificial Analysis Coding IndexClaude Fable 5.1 by 6.781.674.9+6.7
- Toolathlon VerifiedClaude Fable 5.1 by 4.377.873.5+4.3
- HealthBench length-adjustedClaude Fable 5.1 by 3.56056.5+3.5
- GDPval-AA (Elo)GPT-5.5 by 34 rating points17351769+34 rating
- ARC-AGI-1Claude Fable 5.1 by 2.597.595+2.5
- livebench_languageClaude Fable 5.1 by 2.189.587.4+2.1
- livebench_data_analysisGPT-5.5 by 1.380.381.6+1.3
- DeepSWE 1.1tie67.467tie
Questions people ask
Which is better, Claude Fable 5.1 or GPT-5.5?
Claude Fable 5.1 wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. GPT-5.5 wins none, but costs 42% less.
Which is better for coding?
Claude Fable 5.1. It wins 6 of the 6 coding tests both models report; GPT-5.5 wins none.
Which is cheaper?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; GPT-5.5 costs $5.00 and $30.00. That makes GPT-5.5 about 42% cheaper for the same work.
How do you compare the two?
We use the 46 benchmark tests both models have published scores on. The verdict counts the 25 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 21 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.