Anthropic: Claude Sonnet 4.5 vs OpenAI: o3 Pro
Side-by-side comparison of Anthropic: Claude Sonnet 4.5 and OpenAI: o3 Pro. Compare pricing, context window, capabilities, and find out which is better for your workflow.
Verdict
strong confidenceAnthropic: Claude Sonnet 4.5 leads overall
Anthropic: Claude Sonnet 4.5 leads in price and context window, making it the stronger choice for most workflows. OpenAI: o3 Pro remains competitive with advantages in max output.
Best for with Anthropic: Claude Sonnet 4.5
Best for with OpenAI: o3 Pro
Side-by-side
Technical specifications
| Anthropic: Claude Sonnet 4.5 | OpenAI: o3 Pro | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input price | $3/M | $20/M |
| Output price | $15/M | $80/M |
| Context window | 1.0M | 200K |
| Max output | 64K | 100K |
| Capabilities | Tool useVisionReasoning | Tool useVisionReasoning |
| Released | Sep 29, 2025 | Jun 10, 2025 |
Scoring breakdown
How each dimension compares
Price
Anthropic: Claude Sonnet 4.5 leadsAnthropic: Claude Sonnet 4.5
$15/M tokens
OpenAI: o3 Pro
$80/M tokens
Context Window
Anthropic: Claude Sonnet 4.5 leadsAnthropic: Claude Sonnet 4.5
1.0M tokens
OpenAI: o3 Pro
200K tokens
Capabilities
Anthropic: Claude Sonnet 4.5
3/4
OpenAI: o3 Pro
3/4
Max Output
OpenAI: o3 Pro leadsAnthropic: Claude Sonnet 4.5
64K tokens
OpenAI: o3 Pro
100K tokens
Recency
Anthropic: Claude Sonnet 4.5
Sep 2025
OpenAI: o3 Pro
Jun 2025
Related comparisons
Anthropic: Claude 3.5 Sonnet vs OpenAI: o3 Pro
flagship tier · Cross-provider
Anthropic: Claude 3.7 Sonnet (thinking) vs OpenAI: o3 Pro
flagship tier · Cross-provider
Anthropic: Claude 3.7 Sonnet vs OpenAI: o3 Pro
flagship tier · Cross-provider
Anthropic: Claude Opus 4.1 vs OpenAI: o3 Pro
flagship tier · Cross-provider