Claude Sonnet 4.5 vs o3-pro
At a Glance
| Compare | Claude Sonnet 4.5Anthropic |  o3-proOpenAI |
|---|---|---|
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $3.00Anthropic ↗ · Sep 3, 2026 | $20.00Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $15.00Anthropic ↗ · Sep 3, 2026 | $80.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 200K | 200K |
| Model facts checked | Sep 3, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | Claude Sonnet 4.5 | o3-pro |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 4 | O3 |
| Model | Claude Sonnet 4.5 | o3-pro |
| Version | Claude Sonnet 4.5 | o3-pro |
| Lifecycle | active | active |
| Released | 2025-09-29 | 2025-06-10 |
| Knowledge cutoff | 2025-01-01 | 2024-06-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 200K | 200K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
Claude Sonnet 4.5 Capabilities
o3-pro Capabilities
Related Comparisons
All image comparisons →| A | Pair | B | Context |
|---|---|---|---|
Claude Sonnet 4.5Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
Claude Haiku 4.5Anthropic | vs | Claude Sonnet 4.5Anthropic | family variantsimage, text |
Claude Opus 4.5Anthropic | vs | Claude Sonnet 4.5Anthropic | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | Claude Sonnet 4.6Anthropic | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5 NanoOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5 ProOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5.1OpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5.2OpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5.2 ProOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | o3OpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  Qwen3 VL FlashQwen | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Sonnet 4.5 vs o3-pro FAQs
Is Claude Sonnet 4.5 or o3-pro better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Sonnet 4.5 and o3-pro, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Sonnet 4.5 or o3-pro?+
Claude Sonnet 4.5 is $3.00 and o3-pro is $20.00 per million tokens, so Claude Sonnet 4.5 is cheaper on this metric. Claude Sonnet 4.5 is $15.00 and o3-pro is $80.00 per million tokens, so Claude Sonnet 4.5 is cheaper on this metric.
Which has a larger context window, Claude Sonnet 4.5 or o3-pro?+
Both models have the same sourced context window: 200,000 tokens each.
Which performs better in benchmarks, Claude Sonnet 4.5 or o3-pro?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Claude Sonnet 4.5 or o3-pro be self-hosted?+
Both models have the same sourced self-hosting status: unsupported. Claude Sonnet 4.5 is not marked open weight; o3-pro is not marked open weight.
Can Claude Sonnet 4.5 and o3-pro understand images?+
Claude Sonnet 4.5 is documented with image input; o3-pro is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Sonnet 4.5 or o3-pro?+
o3-pro has the larger sourced maximum output. Claude Sonnet 4.5 supports 64,000 tokens and o3-pro supports 100,000 tokens.
Do Claude Sonnet 4.5 and o3-pro support reasoning and tool use?+
Claude Sonnet 4.5: reasoning, tool calling, and image input. o3-pro: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Sonnet 4.5 or o3-pro?+
Claude Sonnet 4.5 has 1 sourced provider route; o3-pro has 2, so o3-pro has broader tracked availability.
Which offers better value, Claude Sonnet 4.5 or o3-pro?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.