Claude Sonnet 4.5 vs o3
Complete pricing and performance comparison between Anthropic's Claude Sonnet 4.5 and OpenAI's o3.
Quick Verdict
Cheaper
o3
1.5x cheaper input, 1.9x cheaper output
Larger Context
Claude Sonnet 4.5
200K vs 200K
Pricing Comparison
| Spec | Claude Sonnet 4.5 | o3 | Difference |
|---|---|---|---|
| Provider | Anthropic | OpenAI | |
| Input / 1M tokens | $3 | $2 | o3 is 33% more expensive |
| Output / 1M tokens | $15 | $8 | o3 is 47% more expensive |
| Context Window | 200K | 200K | Same |
| Max Output | 64K | 100K | |
| Tokenizer | cl100k_base | o200k_base |
Performance Benchmarks
| Metric | Claude Sonnet 4.5 | o3 | Winner |
|---|---|---|---|
| Quality Index | -- | 38 | N/A |
| Output Speed | -- | 79 tok/s | N/A |
| Value (Quality/$) | -- | 19.2 | Higher = better value |
Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.
Cost at Scale
Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).
| Usage | Claude Sonnet 4.5 | o3 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0075 | $0.0044 | o3 saves $0.0031 |
10 requests 10K in / 3K out | $0.075 | $0.044 | o3 saves $0.031 |
100 requests 100K in / 30K out | $0.750 | $0.440 | o3 saves $0.310 |
1,000 requests 1M in / 300K out | $7.50 | $4.40 | o3 saves $3.10 |
10,000 requests 10M in / 3M out | $75.00 | $44.00 | o3 saves $31.00 |
1M requests/mo 1B in / 300M out | $7500.00 | $4400.00 | o3 saves $3100.00 |
Pros & Cons
Claude Sonnet 4.5 Strengths
Part of the Anthropic ecosystem
o3 Strengths
- +Cheaper input tokens
- +Cheaper output tokens
- +Higher max output tokens
When to Use Each Model
Choose Claude Sonnet 4.5 for
- →Projects already integrated with Anthropic's ecosystem
Choose o3 for
- →Budget-conscious projects where cost is the primary factor
- →Generating long-form content or detailed code
Frequently Asked Questions
Which is cheaper, Claude Sonnet 4.5 or o3?
For input tokens, o3 is 1.5x cheaper at $2/1M tokens. For output tokens, o3 is 1.9x cheaper at $8/1M tokens. At typical usage (1M input + 300K output), Claude Sonnet 4.5 costs $7.50 vs o3 at $4.40.
What's the context window difference?
Claude Sonnet 4.5 supports 200K context (200,000 tokens), while o3 supports 200K (200,000 tokens). o3 can handle 1x more context in a single request.
Which model has better benchmarks?
When should I choose Claude Sonnet 4.5 over o3?
Choose Claude Sonnet 4.5 when you need: a Anthropic ecosystem model. Choose o3 when you need: Cheaper input tokens, Cheaper output tokens, Higher max output tokens.
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Claude Sonnet 4.5 = $75.00, o3 = $44.00. At 10K input + 1K output per request (longer conversations): Claude Sonnet 4.5 = $450.00, o3 = $280.00.