Claude Sonnet 5 vs o3
Pricing verdict: Claude Sonnet 5 vs o3: input pricing is tied at $2.00/M, o3 is cheaper for output-heavy usage ($8.00/M output), and Claude Sonnet 5 is better for long-context tasks (1,000,000 tokens).
Direct answer: input pricing is tied. Choose o3 for cheaper output and choose Claude Sonnet 5 when your workload needs longer context.
Compare API pricing, input and output token costs, context windows, and monthly estimates on one page so you can pick the right model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
Claude Sonnet 5
o3
Cost Differences
o3 costs less than Claude Sonnet 5
Quick Recommendation
Winner for direct API pricing: o3. At the default workload, o3 saves about $3.00/month ($36.50/year) versus Claude Sonnet 5.
Feature Comparison
| Feature | Claude Sonnet 5 | o3 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input Price | $2.00/1M tokens | $2.00/1M tokens |
| Output Price | $10.00/1M tokens | $8.00/1M tokens |
| Context Window | 1,000,000 tokens | 1,000,000 tokens |
| Max Output | 128,000 tokens | 131,072 tokens |
| Category | balanced | reasoning |
| Capabilities | textvisioncodereasoningcomputer-use | textreasoningvisioncode |
| Release Date | 6/30/2026 | 4/16/2025 |
Claude Sonnet 5 vs o3: Which Should You Choose?
Choosing between Claude Sonnet 5 and o3 depends on your priorities: cost efficiency, context length, or raw capability. Both models charge $2.00/1M input tokens, but o3 is cheaper on output at $8.00/1M.
These models come from different providers — Anthropic and OpenAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with Anthropic, switching to OpenAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Claude Sonnet 5 is a balanced model while o3 is reasoning. This means they're optimized for different workloads. o3 targets more demanding workloads, while Claude Sonnet 5 provides a cost-effective option for everyday tasks.
Output costs matter too. Claude Sonnet 5 charges $10.00/1M output tokens vs $8.00 for o3. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. o3 has the edge here at $8.00/1M output tokens.
Multimodal capabilities: Both models support vision (image understanding), so you can send images alongside text prompts with either option.
Best Use Cases
Choose Claude Sonnet 5 when:
- • You need more capabilities (computer-use)
- • You're already using Anthropic's API ecosystem
Choose o3 when:
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Pros and Caveats at a Glance
Claude Sonnet 5
- • Input pricing: $2.00/M tokens
- • Output pricing: $10.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 128,000 tokens
Watch out for
- • Higher output cost than o3
o3
- • Input pricing: $2.00/M tokens
- • Output pricing: $8.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Trade-offs are minor in this matchup.
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Claude Sonnet 5 (Anthropic)
o3 (OpenAI)
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Which is cheaper, Claude Sonnet 5 or o3?▼
What is the context window difference between Claude Sonnet 5 and o3?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare Anthropic and OpenAI API pricing beyond this model matchup?▼
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