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Claude Sonnet 4.6 vs Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)

Anthropic · released

Wins 0 of 5 areas

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Anthropic · released

Wins 5 of 5 areas

Coding · Agents · Reasoning · Facts · Long documents

Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) is the stronger all-rounder.

Scores updated · 10 tests both models report · How we compare

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$3.00 to read · $15.00 to write$18Price from Artificial Analysis
Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)$2.00 to read · $10.00 to write$12Price from Artificial Analysis

Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) costs 33% 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 Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) pulls ahead

  • Complex command-line tasks across many fieldsTerminal-Bench 4.0+60.6points aheadClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)63.6Claude Sonnet 4.63
  • Real work tasks from 44 professionsGDPVal+30.3points aheadClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)67Claude Sonnet 4.636.7
  • Research-level physics problemsCritPt+28.3points aheadClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)31.4Claude Sonnet 4.63.1

Where Claude Sonnet 4.6 pulls ahead

No clear win on a test scored out of 100.

Every test, side by side

All 10 tests both models report. The winning score is in its model's colour; marks a score checked independently.

CodingClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)
  • SciCodeClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 10.950.161+10.9

Full coding ranking

AgentsClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)
  • Terminal-Bench 4.0Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 60.6363.6+60.6
  • GDPValClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 30.336.767+30.3

Full agents ranking

ReasoningClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)
  • CritPtClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 28.33.131.4+28.3
  • Humanity's Last ExamClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 21.433.655+21.4

Full reasoning ranking

FactsClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)

Full facts ranking

Long documentsClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)
  • AA-LCRClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 2.78082.7+2.7

Full long documents ranking

Other results2 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.

  • AA IntelligenceClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 25.930.156+25.9
  • AA-OmniscienceClaude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) by 20.112.232.3+20.1

Questions people ask

Which is better, Claude Sonnet 4.6 or Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback)?

Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) wins all five areas where both have results: coding, agents, reasoning, facts and long documents. Claude Sonnet 4.6 wins none.

Which is better for coding?

Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback). It wins the one coding test both models report.

Which is cheaper?

Claude Sonnet 4.6 costs $3.00 per million input tokens and $15.00 per million output tokens; Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) costs $2.00 and $10.00. That makes Claude Sonnet 5.5 (Adaptive Reasoning, Max Effort, Default Fallback) about 33% cheaper for the same work.

How do you compare the two?

We use the 10 benchmark tests both models have published scores on. The verdict counts the 8 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 2 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.