Claude Sonnet 4.5 vs o3 Deep Research
Claude Sonnet 4.5 (2025) and o3 Deep Research (2025) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 4.5 ships a 200k-token context window, while o3 Deep Research ships a 200k-token context window. On pricing, Claude Sonnet 4.5 ranges from $3 to $6/1M input tokens by tier; o3 Deep Research costs $10/1M input tokens. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
o3 Deep Research is safer overall; choose Claude Sonnet 4.5 when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.5 | o3 Deep Research |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | RAG, Agents, and Long context |
| Context window | 200k | 200k |
| Cheapest output | $15/1M tokens | $40/1M tokens |
| Provider routes | 8 tracked | 2 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Claude Sonnet 4.5 has the lower cheapest tracked output price at $15/1M tokens.
- Claude Sonnet 4.5 has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
- Local decision data tags o3 Deep Research for RAG, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Sonnet 4.5
$6,150
Cheapest tracked route/tier: Microsoft Foundry
o3 Deep Research
$18,000
Cheapest tracked route/tier: Vercel AI Gateway
Estimated monthly gap: $11,850. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- o3 Deep Research is $25/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Claude Sonnet 4.5 is $25/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-29 | 2025-10-10 |
| Context window | 200k | 200k |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-12 | 2024-06 |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.5 | o3 Deep Research |
|---|---|---|
| Input price |
| $10/1M tokens |
| Output price |
| $40/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 4.5 | o3 Deep Research |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.