Claude Opus 5.5 vs Claude Sonnet 4.6
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 Opus 5.5 is the stronger all-rounder.Claude Sonnet 4.6 is cheaper.
Scores updated · 30 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 software50Claude Opus 5.55 of 5 tests
- ReasoningHard problems that need careful thinking40Claude Opus 5.54 of 4 tests
- AgentsCarrying out multi-step tasks on its own21Claude Opus 5.52 of 3 tests
- FactsGetting facts right instead of making them up21Claude Opus 5.52 of 3 tests
- Images and chartsUnderstanding pictures, charts and video10Claude Opus 5.51 of 1 test
- MathCompetition and research-level math10Claude Opus 5.51 of 1 test
- Long documentsFinding answers in very long texts10Claude Opus 5.51 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Opus 5.51 of 1 test
Images and charts, math, 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.
Claude Sonnet 4.6 costs 25% 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 Opus 5.5 pulls ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+56.6points ahead
- Short factual questions, answered correctlySimpleQA Verified+39.4points ahead
- Abstract visual puzzles that people can solveARC-AGI-2+33.4points ahead
Where Claude Sonnet 4.6 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+10.2points ahead
- Finds the root cause of IT system incidentsAA IT-Bench SRE+1.6points ahead
Every test, side by side
All 30 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 5.5
- SWE-bench ProClaude Opus 5.5 by 31.889.958.1+31.8
- LMArena · WebDevClaude Opus 5.5 by 294 rating points18151521+294 rating
- LiveBench · Agentic CodingClaude Opus 5.5 by 29.171.742.6+29.1
- SciCodeClaude Opus 5.5 by 16.866.950.1+16.8
- LiveBench · CodingClaude Opus 5.5 by 1089.379.3+10
AgentsClaude Opus 5.5
- Terminal-Bench 4.0Claude Opus 5.5 by 56.659.63+56.6
- GDPValClaude Opus 5.5 by 31.668.336.7+31.6
- AA IT-Bench SREClaude Sonnet 4.6 by 1.638.239.8+1.6
ReasoningClaude Opus 5.5
- ARC-AGI-2Claude Opus 5.5 by 33.491.758.3+33.4
- CritPtClaude Opus 5.5 by 28.631.73.1+28.6
- Humanity's Last ExamClaude Opus 5.5 by 27.861.433.6+27.8
- LiveBench · ReasoningClaude Opus 5.5 by 7.492.284.8+7.4
FactsClaude Opus 5.5
- SimpleQA VerifiedClaude Opus 5.5 by 39.472.232.8+39.4
- AA-Omniscience · AccuracyClaude Opus 5.5 by 25.366.240.9+25.3
- AA-Omniscience · Non-hallucinationClaude Sonnet 4.6 by 10.241.451.6+10.2
Images and chartsClaude Opus 5.5
- MMMU-ProClaude Opus 5.5 by 14.487.773.3+14.4
Following instructionsClaude Opus 5.5
- LiveBench · Instruction FollowingClaude Opus 5.5 by 2.565.763.2+2.5
Other results11 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.
- DeepSWE 1.1Claude Opus 5.5 by 44.274.230+44.2
- AA-OmniscienceClaude Opus 5.5 by 34.246.412.2+34.2
- AA IntelligenceClaude Opus 5.5 by 27.557.630.1+27.5
- HealthBench ProfessionalClaude Opus 5.5 by 21.465.644.2+21.4
- GDPval-AA (Elo)Claude Opus 5.5 by 144 rating points18201676+144 rating
- OfficeQA ProClaude Opus 5.5 by 14.367.753.4+14.3
- ARC-AGI-1Claude Opus 5.5 by 11.597.586+11.5
- livebench_languageClaude Opus 5.5 by 10.286.376.1+10.2
- OfficeQAClaude Opus 5.5 by 10.278.968.7+10.2
- Legal Agent BenchmarkClaude Opus 5.5 by 2.98.35.4+2.9
- livebench_data_analysisClaude Opus 5.5 by 2.380.378+2.3
Questions people ask
Which is better, Claude Opus 5.5 or Claude Sonnet 4.6?
Claude Opus 5.5 wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. Claude Sonnet 4.6 wins none, but costs 25% less.
Which is better for coding?
Claude Opus 5.5. It wins 5 of the 5 coding tests both models report; Claude Sonnet 4.6 wins none.
Which is cheaper?
Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; Claude Sonnet 4.6 costs $3.00 and $15.00. That makes Claude Sonnet 4.6 about 25% cheaper for the same work.
How do you compare the two?
We use the 30 benchmark tests both models have published scores on. The verdict counts the 19 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 11 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.