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Anthropic · Released Sep 28, 2026

Claude Sonnet 5.5

Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing...

ReasoningVision
  • #1LMCA
  • #1ProofBench
  • #1OTIS Mock AIME
  • Top 4%APEX-Agents
Compare in showdown → OpenRouter ↗ All Anthropic models
Released
Sep 28 2026
Context window
1M 128K out
Input / 1M tokens
$2.00
Output / 1M tokens
$10.00

Where to run it

5 providers compared

Cheapest: Google, Amazon Bedrock, Azure +2 more at $2.00 / $10.00 per 1M input / output tokens — 9% less than the priciest option.

ProviderInputOutputCache readContextMax outputUptimevs. best
Googleglobal $2.00 $10.00 $0.101M128K100%24h Cheapest
Amazon Bedrock $2.00 $10.00 $0.101M128K100%24h Cheapest
Azureglobal $2.00 $10.00 $0.101M128K100%24h Cheapest
Claude Platform on AWS $2.00 $10.00 $0.101M128K100%24h Cheapest
Anthropic $2.00 $10.00 $0.101M128K100%24h Cheapest
Googleus $2.20 $11.00 $0.111M128K100%24h +10%
Azureus $2.20 $11.00 $0.111M128K100%24h +10%
Googleeurope $2.20 $11.00 $0.111M128K100%24h +10%

Value

Price vs. performance

1 model scores higher for the same price or lesson GPQA Diamond, e.g. Gemini 4 Argon.
25.3%49.0%72.7%96.4% $0.01$0.10$1.00$10.00$100.00 DeepSeek V4.1 Flash 1017 (DeepSeek) — 89.8% · $0.15/1M in Gemini 4 Argon (Google) — 96.4% · $2.00/1M in Mistral Large 4 (Mistral) — 88.1% · $0.68/1M in GPT-6.1 Sol (OpenAI) — 95.4% · $2.00/1M in GPT-6 Luna (OpenAI) — 90.5% · $0.10/1M in GPT-6 Sol (OpenAI) — 94.3% · $2.00/1M in Grok 4.7 (xAI) — 92.7% · $2.00/1M in DeepSeek V4.1 Flash (DeepSeek) — 89.8% · $0.056/1M in GPT-6 Astra (OpenAI) — 95.8% · $10.00/1M in Qwen3.8 Max (0902) (Qwen) — 92.7% · $2.00/1M in Gemini 3.8 Flash (Google) — 95.4% · $0.82/1M in GLM 5.3 Flash (Z.ai) — 90.1% · $0.037/1M in GLM 5.3 (Z.ai) — 90.9% · $0.079/1M in Gemini 3.7 Flash (Google) — 94.8% · $0.75/1M in DeepSeek V4 Pro 0813 (DeepSeek) — 91.7% · $0.66/1M in Grok 4.6 (xAI) — 94.0% · $2.00/1M in DeepSeek V4 Flash 0731 (DeepSeek) — 91.0% · $0.44/1M in Qwen3.7 Flash (Qwen) — 82.3% · $0.03/1M in Gemini 3.6 Flash (Google) — 94.1% · $0.75/1M in Gemini 3.5 Flash Lite (Google) — 83.3% · $0.30/1M in Kimi K3 (Moonshot AI) — 93.1% · $0.24/1M in GPT-5.6 Luna (OpenAI) — 91.6% · $0.20/1M in GPT-5.6 Terra (OpenAI) — 93.3% · $2.00/1M in GPT-5.6 Sol (OpenAI) — 93.5% · $4.00/1M in Grok 4.5 (xAI) — 93.4% · $2.00/1M in GLM 5.2 (Z.ai) — 91.9% · $0.62/1M in Kimi K2.7 Code (Moonshot AI) — 87.9% · $0.67/1M in Qwen3.7 Plus (Qwen) — 87.9% · $0.32/1M in MiniMax M3 (MiniMax) — 90.9% · $0.30/1M in Qwen3.7 Max (Qwen) — 90.9% · $1.48/1M in Gemini 3.5 Flash (Google) — 92.8% · $1.50/1M in Gemini 3.1 Flash Lite (Google) — 81.8% · $0.25/1M in Grok 4.3 (xAI) — 88.8% · $1.25/1M in Qwen3.5 Plus 2026-04-20 (Qwen) — 84.9% · $0.30/1M in Qwen3.6 Flash (Qwen) — 83.3% · $0.19/1M in Qwen3.6 35B A3B (Qwen) — 84.9% · $0.10/1M in Qwen3.6 27B (Qwen) — 85.9% · $0.25/1M in GPT-5.5 (OpenAI) — 90.7% · $5.00/1M in DeepSeek V4 Pro 0423 (DeepSeek) — 91.7% · $0.95/1M in DeepSeek V4 Flash 0423 (DeepSeek) — 91.0% · $0.091/1M in Kimi K2.6 (Moonshot AI) — 90.8% · $0.65/1M in GLM 5.1 (Z.ai) — 89.9% · $0.97/1M in Gemma 4 26B A4B (Google) — 73.2% · $0.09/1M in Gemma 4 31B (Google) — 75.8% · $0.20/1M in Qwen3.6 Plus (Qwen) — 88.4% · $0.33/1M in GPT-5.4 Nano (OpenAI) — 78.5% · $0.20/1M in GPT-5.4 Mini (OpenAI) — 86.9% · $0.75/1M in Mistral Small 4 (Mistral) — 47.5% · $0.15/1M in Qwen3.5-9B (Qwen) — 79.0% · $0.10/1M in GPT-5.4 Pro (OpenAI) — 94.6% · $30.00/1M in GPT-5.4 (OpenAI) — 93.3% · $2.50/1M in Gemini 3.1 Flash Lite Preview (Google) — 81.8% · $0.25/1M in Qwen3.5-35B-A3B (Qwen) — 83.5% · $0.15/1M in Gemini 3.1 Pro Preview (Google) — 94.4% · $2.00/1M in Qwen3.5 397B A17B (Qwen) — 86.4% · $0.39/1M in GLM 5 (Z.ai) — 87.8% · $0.60/1M in GLM 4.7 Flash (Z.ai) — 60.5% · $0.061/1M in GLM 4.7 (Z.ai) — 83.3% · $0.54/1M in Gemini 3 Flash Preview (Google) — 89.4% · $0.50/1M in GPT-5.2 (OpenAI) — 91.4% · $1.75/1M in Ministral 3 8B 2512 (Mistral) — 27.2% · $0.15/1M in Ministral 3 3B 2512 (Mistral) — 25.3% · $0.10/1M in Mistral Large 3 2512 (Mistral) — 51.3% · $0.50/1M in GPT-5.1 (OpenAI) — 87.6% · $1.25/1M in GPT-5 (OpenAI) — 86.2% · $1.25/1M in GPT-5 Mini (OpenAI) — 75.0% · $0.25/1M in GPT-5 Nano (OpenAI) — 69.4% · $0.05/1M in gpt-oss-120b (OpenAI) — 75.8% · $0.15/1M in gpt-oss-20b (OpenAI) — 60.8% · $0.018/1M in Qwen3 30B A3B Instruct 2507 (Qwen) — 55.6% · $0.09/1M in Qwen3 235B A22B Thinking 2507 (Qwen) — 80.0% · $0.45/1M in Qwen3 235B A22B Instruct 2507 (Qwen) — 70.7% · $0.09/1M in Gemini 2.5 Pro (Google) — 85.3% · $1.25/1M in Gemini 2.5 Pro Preview 06-05 (Google) — 85.3% · $1.25/1M in R1 0528 (DeepSeek) — 76.3% · $0.50/1M in Qwen3 30B A3B (Qwen) — 61.7% · $0.12/1M in Qwen3 14B (Qwen) — 63.8% · $0.12/1M in Qwen3 32B (Qwen) — 65.7% · $0.08/1M in Claude Haiku 5.5 (Anthropic) — 89.6% · $0.10/1M in Claude Opus 5.5 (Anthropic) — 90.6% · $4.00/1M in Claude Opus 5 (Anthropic) — 93.9% · $5.00/1M in Claude Sonnet 5 (Anthropic) — 90.5% · $2.00/1M in Claude Fable 5 (Anthropic) — 85.9% · $10.00/1M in Claude Opus 4.8 (Anthropic) — 91.0% · $5.00/1M in Claude Opus 4.7 (Anthropic) — 90.1% · $5.00/1M in Claude Sonnet 4.6 (Anthropic) — 87.4% · $3.00/1M in Claude Opus 4.6 (Anthropic) — 90.5% · $5.00/1M in Claude Opus 4.5 (Anthropic) — 86.1% · $5.00/1M in Claude Haiku 4.5 (Anthropic) — 71.2% · $1.00/1M in Claude Sonnet 4.5 (Anthropic) — 82.3% · $3.00/1M in Claude Opus 4.1 (Anthropic) — 77.3% · $15.00/1M in Claude Sonnet 5.5 (Anthropic) — 95.6% · $2.00/1M in Claude Sonnet 5.5

Claude Sonnet 5.5 Other Anthropic Other labs Value frontier · GPQA Diamond vs. input price per 1M tokens (log scale) · Drag to pan, pinch or Ctrl + scroll to zoom, double-click to zoom in.

Benchmarks

21 benchmark scores

BenchmarkScoreRankLeader
FrontierSWESoftware engineering · Ultra-long-horizon engineering tasks with a 20-hour budget each 61.9% #3of 19 GPT-6 Astra65.5%
CursorBenchSoftware engineering · Ambiguous multi-file tasks drawn from real Cursor sessions 55.5% #2of 16 Claude Opus 5.557.8%
FrontierCodeSoftware engineering · Mergeable fixes for hard open-source issues 52.1% #5of 41 Claude Opus 5.554.6%
SciCodeSoftware engineering · Research-coding problems from the natural sciences 61.0% #4of 93 Claude Opus 5.566.9%
WeirdML v3Software engineering · Unfamiliar ML and data tasks with vague goals 19.9% #6of 22 GPT-6 Astra42.2%
APEX-AgentsAgents & computer use · Long professional tasks in banking, consulting and law 75.5% #2of 51 Gemini 4 Argon82.4%
Vending-Bench 2Agents & computer use · Run a simulated vending business for a year (final balance) $11,165 #5of 61 GPT-6 Astra$15,515
GDP.pdfWriting & content · Answer questions about real professional PDFs 31.4% #3of 38 GPT-6.1 Sol35.0%
SimpleQA VerifiedWriting & content · Factual accuracy on 1,000 short questions 46.5% #32of 66 Gemini 4 Argon76.0%
WebDev ArenaDesign & visual · People vote on which model builds the better website (Elo) 1786 #3of 88 Claude Opus 5.51820
Blueprint-Bench 2Design & visual · Turn apartment photos into 2D floor plans 39.3% #5of 32 Gemini 4 Argon54.4%
Furniture AssemblyDesign & visual · Spot mistakes in photos of IKEA builds 75.0% #4of 34 Claude Opus 5.583.3%
GPQA DiamondReasoning & knowledge · PhD-level biology, chemistry and physics questions 95.6% #3of 92 Gemini 4 Argon96.4%
Humanity's Last ExamReasoning & knowledge · Expert questions across 100+ subjects 46.1% #4of 23 GPT-6 Astra54.8%
CritPtReasoning & knowledge · Open-ended, research-level physics problems 31.4% #5of 96 GPT-5.6 Sol32.3%
Chess PuzzlesReasoning & knowledge · Find the single best move in 100 new puzzles 59.0% #9of 70 GPT-6 Astra76.0%
LMCAReasoning & knowledge · Judge the quality of conceptual arguments like experts 68.3% #1of 96 This model
FrontierMathMaths · Expert-written problems, undergrad to early research (tiers 1–3) 88.8% #7of 72 GPT-6.1 Sol93.7%
FrontierMath Tier 4Maths · Exceptionally hard research-level problems 80.5% #8of 62 GPT-6.1 Sol100.0%
ProofBenchMaths · Graduate maths proofs verified in Lean 4 100.0% #1of 70 This model
OTIS Mock AIMEMaths · Competition-style problems harder than MATH Level 5 100.0% #1of 90 Gemini 4 Argon100.0%

Specs

Details

Model ID
anthropic/claude-sonnet-5.5
Developer
Anthropic
Release date
Sep 28, 2026 ·
Context window
1,000,000 tokens
Max output
128,000 tokens
API price
$2.00 / $10.00 per 1M input / output tokens
Providers
5
Input types
text, image, file
Reasoning
Yes
Tool calling
Yes
Open weights
No
Free tier
No

Release date, prices and providers from OpenRouter's catalog; buying directly from a provider can cost a little differently. Uptime is the share of OpenRouter requests each provider served over the last day. Benchmark scores are the best result per benchmark from Epoch AI, licensed CC BY 4.0. Rank counts every model tracked here with a score.