Key Takeaways
Claude Sonnet 4.5 wins:
- Larger context window
o3 wins:
- Cheaper input tokens
- Cheaper output tokens
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Better at math
Price Advantage
o3
Benchmark Advantage
o3
Context Window
Claude Sonnet 4.5
Speed
o3
Pricing Comparison
Price Comparison
| Metric | Claude Sonnet 4.5 | o3 | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $3.00 | $2.00 | o3 |
| Output (per 1M tokens) | $15.00 | $8.00 | o3 |
| Cache Read (per 1M) | $0.30 | $0.50 | Claude Sonnet 4.5 |
| Cache Write (per 1M) | $3.75 | N/A | Claude Sonnet 4.5 |
Using a 3:1 input/output ratio, o3 is 42% cheaper overall.
Claude Sonnet 4.5 Providers
No provider data available
o3 Providers
No provider data available
Benchmark Comparison
8
Benchmarks Compared
1
Claude Sonnet 4.5 Wins
5
o3 Wins
Benchmark Scores
| Benchmark | Claude Sonnet 4.5 | o3 | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 37.1 | 38.4 | |
Coding Index Code generation & understanding | 33.5 | 38.4 | |
Math Index Mathematical reasoning | 37.0 | 88.3 | |
MMLU Pro Academic knowledge | 86.0 | 85.3 | |
GPQA Graduate-level science | 72.7 | 82.7 | |
LiveCodeBench Competitive programming | 59.0 | 80.8 | |
Aider Real-world code editing | - | 81.3 | - |
AIME Competition math | - | 90.3 | - |
o3 shows stronger mathematical reasoning abilities.
Cost vs Quality
X-axis:
Y-axis:
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Claude Sonnet 4.5
Other models
Context & Performance
Context Window
Claude Sonnet 4.5
1,000,000
tokens
o3
200,000
tokens
Claude Sonnet 4.5 has a 80% larger context window.
Speed Performance
| Metric | Claude Sonnet 4.5 | o3 | Winner |
|---|---|---|---|
| Tokens/second | 47.8 tok/s | 61.1 tok/s | |
| Time to First Token | 1.25s | 8.78s |
o3 responds 28% faster on average.
Capabilities
Feature Comparison
| Feature | Claude Sonnet 4.5 | o3 |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | Claude Sonnet 4.5 | o3 |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | Anthropic | OpenAI |
| Released | Sep 2025 | Apr 2025 |
Claude Sonnet 4.5 Modalities
Input
textimagefile
Output
text
o3 Modalities
Input
imagetextfile
Output
text