AI Models · Compare
Claude 4 Sonnet vs Claude 3.5 Sonnet
Side-by-side intelligence, speed, price, benchmarks, strengths and weaknesses.
Anthropic
Claude 4 Sonnet
ProprietaryFeb 2026
The Anthropic sweet spot — Opus-class coding at a fraction of the price.
Anthropic
Claude 3.5 Sonnet
ProprietaryOct 2024
The model that made coding agents viable — still a top pick.
Head to head
Spec
Claude 4 Sonnet
Claude 3.5 Sonnet
Intelligence index↑ better
Winner75
71
Speed↑ better
Winner95 tok/s
85 tok/s
Time to first token↓ better
Winner0.85 s
0.9 s
Context window↑ better
Winner500k
200k
Max output↑ better
Winner16k
8k
Input price↓ better
$3.00 / 1M tokens
$3.00 / 1M tokens
Output price↓ better
$15.00 / 1M tokens
$15.00 / 1M tokens
Blended price↓ better
$6.00 / 1M tokens
$6.00 / 1M tokens
License
Proprietary
Proprietary
Input modalities
text, image
text, image
Output modalities
text
text
Benchmark showdown
MMLU
Claude 4 Sonnet
88.5
Claude 3.5 Sonnet
88.3
MMLU Pro
Claude 4 Sonnet
75.2
Claude 3.5 Sonnet
74.0
GPQA
Claude 4 Sonnet
58.0
Claude 3.5 Sonnet
59.4
MATH
Claude 4 Sonnet
82.0
Claude 3.5 Sonnet
78.3
HumanEval
Claude 4 Sonnet
93.2
Claude 3.5 Sonnet
92.0
Strengths, weaknesses and best-for
Claude 4 Sonnet
Strengths
- Best $/HumanEval ratio
- Fast
- 500k context
Weaknesses
- Behind Opus on hardest reasoning
Best for
- Production coding tools
- Long-context RAG
- Tool use
Claude 3.5 Sonnet
Strengths
- Excellent at code
- Strong writing
- Long context
Weaknesses
- Superseded by Claude 4 Sonnet for new builds
Best for
- Coding tasks
- Long-form writing
- Agentic workflows
Quick verdict
- Pick Claude 4 Sonnet if you want it smarter, faster and longer context.
Auto-generated from the spec sheet. Always validate on your own evals.
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