Glimmer Index
Plus $4/mo

Claude Sonnet 4.5

Anthropic · Released Sep 29, 2025 · Closed weights

Balanced Claude model for coding, analysis, agent workflows, and cost control

Strongest at
Writing
Top 29% of the past year's models · 2 of 4 benchmarks
Price per 1M tokens
$3 / $15
input / output · Anthropic
Context window
200K
tokens in · 64K out
Since the last one
130 days
after Claude Sonnet 4
Lab announcement ↗Open in the timeline

Capability profile

Scored against 91 models released in the past year. 50 is the average model; further out is better.

This modelClaude Sonnet 4Median of the past year
5090Median of the past yearClaude Sonnet 4Coding: 47 · Better than 25%Writing: 61 · Top 29%Reasoning: 55 · Better than 40%Math: 42 · Better than 10%Science: 48 · Better than 7%CodingWritingReasoningMathScience
Coding47−1.6Better than 25% · 1 test
Writing61+6.8Top 29%
Reasoning55+11.2Better than 40% · 1 test
Math42−14.8Better than 10% · 1 test
Science48−0.9Better than 7%

No results yet: Reading & documents, Visual reasoning, Computer use

Where these scores come from

Each capability combines the published benchmarks listed here, rescaled so 50 is the reference average and 15 points is one standard deviation. A hollow dot rests on a single benchmark.

Price against capability

The shaded corner holds anything better and cheaper. Prices blend input and output 3 to 1.

13 models from the past year score higher on Writing for less: Kimi K3.1 Pro, Muse Spark 1.3, Gemini 3.8 Flash and 10 more.

$0.1$0.3$1$3$10204060Kimi K3.1 Pro: 70, $4 per 1MClaude Haiku 5.5: 46, $0.2 per 1MMistral Large 4: 41, $2.06 per 1MGemini 4 Argon: 63, $4 per 1MGPT-6.1 Sol: 64, $4 per 1MClaude Sonnet 5.5: 55, $4 per 1MGPT-6 Sol: 61, $4 per 1MGPT-6 Luna: 22, $0.2 per 1MClaude Opus 5.5: 65, $8 per 1MGrok 4.7: 64, $3 per 1MDeepSeek V4.1 Flash: 56, $0.21 per 1MGPT-6 Astra: 69, $20 per 1MMuse Spark 1.3: 65, $2 per 1MGemini 3.8 Flash: 65, $1.5 per 1MClaude Fable 5.1: 69, $20 per 1MGLM-5.3-Flash: 15, $0.24 per 1MDeepSeek V4 Flash Vision Exp: 56, $0.32 per 1MQwen3.8 27B: 52, $1.12 per 1MGLM-5.3: 65, $2.15 per 1MGemini 3.7 Flash: 61, $1.5 per 1MDeepSeek V4 Pro 0813: 49, $0.99 per 1MQwen3.8 2.4T A95B: 62, $3 per 1MGrok 4.6: 44, $3 per 1MMuse Glimmer 30B: 59, $0.52 per 1MMuse Spark 1.2: 62, $2 per 1MQwen3.8 Max: 57, $3 per 1MDeepSeek V4 Flash 0731: 52, $0.15 per 1MClaude Opus 5: 64, $10 per 1MGemini 3.6 Flash: 63, $1.5 per 1MGemini 3.5 Flash Lite: 53, $0.85 per 1MKimi K3: 64, $6 per 1MGPT-5.6 Terra: 57, $4.5 per 1MGPT-5.6 Sol: 65, $8 per 1MGPT-5.6 Luna: 53, $0.45 per 1MGrok 4.5: 44, $3 per 1MClaude Sonnet 5: 57, $4 per 1MGLM-5.2: 55, $2.15 per 1MKimi K2.7 Code: 23, $1.71 per 1MClaude Fable 5: 68, $20 per 1MClaude Opus 4.8: 62, $10 per 1MQwen3.7 Max: 48, $3.75 per 1MGemini 3.5 Flash: 56, $3.38 per 1MDeepSeek V4 Pro: 54, $1.19 per 1MDeepSeek V4 Flash: 52, $0.11 per 1MGPT-5.5: 64, $11.2 per 1MQwen3.6 27B: 16, $1.35 per 1MKimi K2.6: 56, $1.71 per 1MQwen3.6 Max Preview: 44, $2.92 per 1MGrok 4.3: 29, $1.56 per 1MGrok Build 0.1: 43, $1.25 per 1MClaude Opus 4.7: 61, $10 per 1MMuse Spark 1.1: 58, $2 per 1MGLM-5.1: 56, $2.15 per 1MGemma 4 31B IT: 54, $0.25 per 1MGemma 4 26B A4B IT: 51, $0.14 per 1MQwen3.6 Plus: 31, $1.12 per 1MGPT-5.4 nano: 49, $0.46 per 1MGPT-5.4 mini: 52, $1.69 per 1MGPT-5.4: 63, $5.62 per 1MGemini 3.1 Flash Lite Preview: 43, $0.56 per 1MQwen3.5 35B-A3B: 39, $0.69 per 1MQwen3.5 27B: 52, $0.82 per 1MQwen3.5 122B-A10B: 47, $1.1 per 1MGemini 3.1 Pro Preview: 57, $4.5 per 1MClaude Sonnet 4.6: 57, $6 per 1MQwen3.5 397B-A17B: 59, $1.35 per 1MGLM-5: 60, $1.55 per 1MClaude Opus 4.6: 56, $10 per 1MKimi K2.5: 62, $1 per 1MGLM-4.7: 58, $1 per 1MGemini 3 Flash Preview: 49, $1.12 per 1MGPT-5.2 Codex: 46, $4.81 per 1MGPT-5.2: 59, $4.81 per 1MMistral Large 3: 38, $0.75 per 1MMinistral 3 14B: 28, $0.2 per 1MDeepSeek V3.2: 49, $0.32 per 1MKimi K2 Thinking: 61, $1.07 per 1MClaude Sonnet 4.5: 61, $6 per 1MClaude Sonnet 4.5Price per 1M tokens →↑ Writing$0.1$1$10204060Kimi K3.1 Pro: 70, $4 per 1MClaude Haiku 5.5: 46, $0.2 per 1MMistral Large 4: 41, $2.06 per 1MGemini 4 Argon: 63, $4 per 1MGPT-6.1 Sol: 64, $4 per 1MClaude Sonnet 5.5: 55, $4 per 1MGPT-6 Sol: 61, $4 per 1MGPT-6 Luna: 22, $0.2 per 1MClaude Opus 5.5: 65, $8 per 1MGrok 4.7: 64, $3 per 1MDeepSeek V4.1 Flash: 56, $0.21 per 1MGPT-6 Astra: 69, $20 per 1MMuse Spark 1.3: 65, $2 per 1MGemini 3.8 Flash: 65, $1.5 per 1MClaude Fable 5.1: 69, $20 per 1MGLM-5.3-Flash: 15, $0.24 per 1MDeepSeek V4 Flash Vision Exp: 56, $0.32 per 1MQwen3.8 27B: 52, $1.12 per 1MGLM-5.3: 65, $2.15 per 1MGemini 3.7 Flash: 61, $1.5 per 1MDeepSeek V4 Pro 0813: 49, $0.99 per 1MQwen3.8 2.4T A95B: 62, $3 per 1MGrok 4.6: 44, $3 per 1MMuse Glimmer 30B: 59, $0.52 per 1MMuse Spark 1.2: 62, $2 per 1MQwen3.8 Max: 57, $3 per 1MDeepSeek V4 Flash 0731: 52, $0.15 per 1MClaude Opus 5: 64, $10 per 1MGemini 3.6 Flash: 63, $1.5 per 1MGemini 3.5 Flash Lite: 53, $0.85 per 1MKimi K3: 64, $6 per 1MGPT-5.6 Terra: 57, $4.5 per 1MGPT-5.6 Sol: 65, $8 per 1MGPT-5.6 Luna: 53, $0.45 per 1MGrok 4.5: 44, $3 per 1MClaude Sonnet 5: 57, $4 per 1MGLM-5.2: 55, $2.15 per 1MKimi K2.7 Code: 23, $1.71 per 1MClaude Fable 5: 68, $20 per 1MClaude Opus 4.8: 62, $10 per 1MQwen3.7 Max: 48, $3.75 per 1MGemini 3.5 Flash: 56, $3.38 per 1MDeepSeek V4 Pro: 54, $1.19 per 1MDeepSeek V4 Flash: 52, $0.11 per 1MGPT-5.5: 64, $11.2 per 1MQwen3.6 27B: 16, $1.35 per 1MKimi K2.6: 56, $1.71 per 1MQwen3.6 Max Preview: 44, $2.92 per 1MGrok 4.3: 29, $1.56 per 1MGrok Build 0.1: 43, $1.25 per 1MClaude Opus 4.7: 61, $10 per 1MMuse Spark 1.1: 58, $2 per 1MGLM-5.1: 56, $2.15 per 1MGemma 4 31B IT: 54, $0.25 per 1MGemma 4 26B A4B IT: 51, $0.14 per 1MQwen3.6 Plus: 31, $1.12 per 1MGPT-5.4 nano: 49, $0.46 per 1MGPT-5.4 mini: 52, $1.69 per 1MGPT-5.4: 63, $5.62 per 1MGemini 3.1 Flash Lite Preview: 43, $0.56 per 1MQwen3.5 35B-A3B: 39, $0.69 per 1MQwen3.5 27B: 52, $0.82 per 1MQwen3.5 122B-A10B: 47, $1.1 per 1MGemini 3.1 Pro Preview: 57, $4.5 per 1MClaude Sonnet 4.6: 57, $6 per 1MQwen3.5 397B-A17B: 59, $1.35 per 1MGLM-5: 60, $1.55 per 1MClaude Opus 4.6: 56, $10 per 1MKimi K2.5: 62, $1 per 1MGLM-4.7: 58, $1 per 1MGemini 3 Flash Preview: 49, $1.12 per 1MGPT-5.2 Codex: 46, $4.81 per 1MGPT-5.2: 59, $4.81 per 1MMistral Large 3: 38, $0.75 per 1MMinistral 3 14B: 28, $0.2 per 1MDeepSeek V3.2: 49, $0.32 per 1MKimi K2 Thinking: 61, $1.07 per 1MClaude Sonnet 4.5: 61, $6 per 1MClaude Sonnet 4.5Price per 1M tokens →↑ Writing

Anthropic $3 / $15 · OpenRouter $3 / $15 · Cached input $0.3

Since Claude Sonnet 4

6 releases in the Claude Sonnet line.

Claude Sonnet 3.7Feb 19, 202592dClaude Sonnet 4May 22, 2025130dClaude Sonnet 4.5Sep 29, 2025141dClaude Sonnet 4.6Feb 17, 2026133dClaude Sonnet 5Jun 30, 202690dClaude Sonnet 5.5Sep 28, 2026
Released130 days later
Context200Ksame
Coding47−1.6
Writing61+6.8
Reasoning55+11.2
Math42−14.8
Science48−0.9

A newer release is out: Claude Sonnet 5.5.

ECI STANDING#75 of 270
SCORE146.74145.03–148.31 CI
FRONTIER LAGLaunched 3.6 months behindScores about what o3-pro did in June 2025.
SCORES LIKE THESE MODELS
MiniMax-M3MiniMax · Jun 2026146.87
Qwen3.5 397B-A17BAlibaba · Feb 2026146.8o3OpenAI · Apr 2025146.73
MiniMax-M2.5MiniMax · Feb 2026146.59
Full Epoch Capabilities Index ranking ↗

Epoch benchmark boards

Best result on each board it has run. The tick marks the leader.

Cybench
60%#3 of 22
DTBench
83%#69 of 179
DeepResearch Bench
48%#11 of 26
SimpleBench
54%#38 of 89
Terminal Bench
46%#24 of 50
GSO-Bench
15%#18 of 35
ProofBench
19%#52 of 81
Remote Labor Index
2%#12 of 15

Anthropic's past year

12 release days in the past year, about one every 30 days. The next is expected around Nov 12, 2026. Forecasts ↗

NovDecJanFebMarAprMayJunJulAugSepOctNov

Specifications

RELEASE DATESep 29, 2025
WEIGHTSClosed weights
CONTEXT WINDOW200K
MAX OUTPUT64K
REASONINGNot listed
TOOL CALLINGNot listed
INPUTStext, image/jpeg, image/png, image/gif, image/webp, application/pdf
OUTPUTStext

Models.dev record ↗

Specifications and prices from Models.dev; availability and limits may differ by provider. Benchmarks from Epoch AI (CC BY 4.0), LiveBench and the other sources named above.