Last verified 2025-09-22 (left) · 2025-09-22 (right)
Claude Sonnet 3.7 (Legacy) vs o3-pro — Pricing & Capability Comparison
Claude Sonnet 3.7 (Legacy) charges $3.00 per million input tokens and $15.00 per million output tokens. o3-pro comes in at $20.00 / $80.00. Context windows span 200K vs 200K tokens respectively.
TL;DR — Quick Comparison
- ✓Claude Sonnet 3.7 (Legacy) is cheaper overall: $18.00 per 1M tokens (in+out) vs $100.00 for o3-pro — saves $82.00 per 1M tokens
- ✓Input pricing: Claude Sonnet 3.7 (Legacy) $3.00/1M vs o3-pro $20.00/1M
- ✓Output pricing: Claude Sonnet 3.7 (Legacy) $15.00/1M vs o3-pro $80.00/1M
- ✓Context window: Claude Sonnet 3.7 (Legacy) offers more (200K vs 200K)
- ✓Use our calculator below to estimate costs for your specific usage pattern
Input price (per 1M)
Claude Sonnet 3.7 (Legacy)
$3.00
o3-pro
$20.00
Claude Sonnet 3.7 (Legacy) leads here
Output price (per 1M)
Claude Sonnet 3.7 (Legacy)
$15.00
o3-pro
$80.00
Claude Sonnet 3.7 (Legacy) leads here
Context window
Claude Sonnet 3.7 (Legacy)
200,000 tokens
o3-pro
200,000 tokens
Claude Sonnet 3.7 (Legacy) leads here
Cached input
Claude Sonnet 3.7 (Legacy)
Not published
o3-pro
Not published
No published data
Cost comparison for 10K-token workloads
Side-by-side pricing for identical workloads (10,000 total tokens per request) across different distributions.
| Scenario | Claude Sonnet 3.7 (Legacy) | o3-pro |
|---|---|---|
Balanced conversation 50% input · 50% output | $0.0900 | $0.500 |
Input-heavy workflow 80% input · 20% output | $0.0540 | $0.320 |
Generation heavy 30% input · 70% output | $0.114 | $0.620 |
Cached system prompt 90% cached input · 10% fresh output | $0.0420 | $0.260 |
Frequently asked questions
Which is cheaper: Claude Sonnet 3.7 (Legacy) or o3-pro?
Claude Sonnet 3.7 (Legacy) is cheaper for input tokens at $3.00 per 1M tokens compared to $20.00. For output, Claude Sonnet 3.7 (Legacy) costs $15.00 per 1M tokens versus $80.00 for o3-pro.
What is the cost per 1M tokens for Claude Sonnet 3.7 (Legacy)?
Claude Sonnet 3.7 (Legacy) pricing: $3.00 per 1M input tokens and $15.00 per 1M output tokens. Context window: 200,000 tokens.
What is the cost per 1M tokens for o3-pro?
o3-pro pricing: $20.00 per 1M input tokens and $80.00 per 1M output tokens. Context window: 200,000 tokens.
How much does it cost per 1K tokens?
Per 1K tokens: Claude Sonnet 3.7 (Legacy) costs $0.0030 input / $0.0150 output. o3-pro costs $0.0200 input / $0.0800 output. This is useful for calculating small-scale usage costs.
Which model supports a larger context window?
Claude Sonnet 3.7 (Legacy) offers 200,000 tokens (200K) versus 200K for o3-pro.
What is the estimated monthly cost for typical usage?
For a typical workload of 10M input + 2M output tokens per month: Claude Sonnet 3.7 (Legacy) would cost approximately $60.00, while o3-pro would cost $360.00. Claude Sonnet 3.7 (Legacy) is more economical for this usage pattern.
Do these models support prompt caching?
Claude Sonnet 3.7 (Legacy) does not publish cached pricing. o3-pro does not publish cached pricing.
Which model is best for my use case?
Choose Claude Sonnet 3.7 (Legacy) for cost-sensitive applications with high input volume. Choose Claude Sonnet 3.7 (Legacy) if you need 200K context for long documents or conversations. Consider prompt caching if you have repeated context. Use our token calculator to model your specific usage pattern.