AI model comparison
Claude Sonnet 4.5 vs o1
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
Anthropic
Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows.
- Input / 1M
- $3
- Output / 1M
- $15
- Context
- 1M
OpenAI
o1
The latest and strongest model family from OpenAI, o1 is designed to spend more time thinking before responding.
- Input / 1M
- $15
- Output / 1M
- $60
- Context
- 200K
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
Claude Sonnet 4.5
4.4x cheaper for a typical chat
Higher intelligence score
Claude Sonnet 4.5
20.7 vs 15.2 on Artificial Analysis
Larger context window
Claude Sonnet 4.5
1M vs 200K tokens
Newer release
Claude Sonnet 4.5
Released September 29, 2025
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Claude Sonnet 4.520.7o115.2Coding index
Claude Sonnet 4.552.1o139.7Agentic index
Claude Sonnet 4.515.8o1Not availablePricing
Claude Sonnet 4.5 vs o1 API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | Claude Sonnet 4.5 | o1 |
|---|---|---|
| Input tokensPer 1M tokens | $3 | $15 |
| Output tokensPer 1M tokens | $15 | $60 |
| Cached input (read)Per 1M tokens | $0.30 | $7.50 |
| Cache writePer 1M tokens | $3.75 | Not available |
| Long-context pricingPer 1M tokens, for very long prompts | $6 in / $22.50 out above 200K | Same rate at any length |
| Web searchPer request | $0.01 | $0.01 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Claude Sonnet 4.5$13.50o1$60Coding task
30K in, 4K out
Claude Sonnet 4.5$150$69 cachedo1$690$465 cachedLong document summary
150K in, 2K out
Claude Sonnet 4.5$480$75 cachedo1$2370$1245 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | Claude Sonnet 4.5 | o1 |
|---|---|---|
| Context window | 1M tokens | 200K tokens |
| Max output | 64K tokens | 100K tokens |
| Input types | File, Image, Text | File, Image, Text |
| Output types | Text | Text |
| Reasoning effort levels | Not available | Not available |
| Default reasoning effort | Not available | Not available |
| Release date | September 29, 2025 | December 17, 2024 |
Features
Supported features
API features available for each model.
| Metric | Claude Sonnet 4.5 | o1 |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Supported | Not supported |
| Stop sequences | Supported | Not supported |
| Deterministic seed | Not supported | Supported |
| Verbosity control | Not supported | Not supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
Claude Sonnet 4.5View full model details- Claude Sonnet 4.5 vs Claude Sonnet 4.6
- Claude Sonnet 4.5 vs Claude Haiku 4.5
- Claude Sonnet 4.5 vs Claude Opus 4.5
- Claude Sonnet 4.5 vs GPT-5.1
- Claude Sonnet 4.5 vs GPT-5.1-Codex
- Claude Sonnet 4.5 vs Gemini 2.5 Pro
- Claude Sonnet 4.5 vs GPT-5
- Claude Sonnet 4.5 vs Claude Opus 4.1
- Claude Sonnet 4.5 vs o3 Pro
- Claude Sonnet 4.5 vs Qwen3.5 397B A17B
- Claude Sonnet 4.5 vs o3
- Claude Sonnet 4.5 vs Claude Sonnet 4
Our take
Claude Sonnet 4.5 is 4.4x cheaper for a typical chat. Claude Sonnet 4.5 scores higher on the Artificial Analysis Intelligence Index (20.7 vs 15.2). Claude Sonnet 4.5 has the larger context window (1M vs 200K tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Claude Sonnet 4.5 or o1 cheaper?
Claude Sonnet 4.5 is cheaper for a typical chat (2K input tokens and 500 output tokens). Claude Sonnet 4.5 costs $3 per 1M input tokens and $15 per 1M output tokens, while o1 costs $15 per 1M input tokens and $60 per 1M output tokens.
Which has a bigger context window, Claude Sonnet 4.5 or o1?
Claude Sonnet 4.5 supports up to 1M tokens of context, compared with 200K for o1.
Is Claude Sonnet 4.5 smarter than o1?
On the Artificial Analysis Intelligence Index, Claude Sonnet 4.5 scores 20.7 and o1 scores 15.2, putting Claude Sonnet 4.5 ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Claude Sonnet 4.5 and o1 at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Claude Sonnet 4.5 and o1 answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Claude Sonnet 4.5 and o1 at the same time. Compare the answers side by side and keep the best one.