GPT-5.1 vs o1 Pro
GPT-5.1 vs o1 Pro: GPT-5.1 is cheaper for input-heavy usage ($1.25/M vs $150.00/M input tokens), while GPT-5.1 is better for long-context tasks (1,000,000 tokens).
Direct answer: choose GPT-5.1 for lower token spend and choose GPT-5.1 when your workload needs longer context.
Compare input and output token pricing, context windows, and monthly cost estimates on one page so you can pick the cheaper model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
GPT-5.1
o1 Pro
Cost Differences
o1 Pro costs more than GPT-5.1
Quick Recommendation
Winner for direct API pricing: GPT-5.1. At the default workload, GPT-5.1 saves about $1,331.25/month ($16,196.875/year) versus o1 Pro.
Feature Comparison
| Feature | GPT-5.1 | o1 Pro |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price | $1.25/1M tokens | $150.00/1M tokens |
| Output Price | $10.00/1M tokens | $600.00/1M tokens |
| Context Window | 1,000,000 tokens | 200,000 tokens |
| Max Output | 131,072 tokens | 100,000 tokens |
| Category | flagship | flagship |
| Capabilities | textvisionaudiocodereasoning | textvisioncodereasoning |
| Release Date | 11/12/2025 | 12/17/2024 |
GPT-5.1 vs o1 Pro: Which Should You Choose?
Choosing between GPT-5.1 and o1 Pro depends on your priorities: cost efficiency, context length, or raw capability. GPT-5.1 is the more affordable option at $1.25/1M input tokens — 99% cheaper than o1 Pro. Meanwhile, GPT-5.1 offers a significantly larger context window at 1,000,000 tokens vs 200,000 for o1 Pro.
Both models are in the flagship category, making this a direct head-to-head comparison. At scale — say 10,000 requests per day — the cost difference adds up: GPT-5.1 would save you roughly $133,125.00/month compared to o1 Pro. For startups and indie developers, that difference can be significant.
Output costs matter too. GPT-5.1 charges $10.00/1M output tokens vs $600.00 for o1 Pro. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. GPT-5.1 has the edge here at $10.00/1M output tokens.
Multimodal capabilities: Both models support vision (image understanding), so you can send images alongside text prompts with either option.
Best Use Cases
Choose GPT-5.1 when:
- • Budget is a primary concern
- • You need a larger context window (1,000,000 tokens)
- • You need more capabilities (audio)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Choose o1 Pro when:
- • You're already using OpenAI's API ecosystem
Pros and Caveats at a Glance
GPT-5.1
- • Input pricing: $1.25/M tokens
- • Output pricing: $10.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Trade-offs are minor in this matchup.
o1 Pro
- • Input pricing: $150.00/M tokens
- • Output pricing: $600.00/M tokens
- • Context window: 200,000 tokens
- • Max output: 100,000 tokens
Watch out for
- • Higher input cost than GPT-5.1
- • Higher output cost than GPT-5.1
- • Smaller context window than GPT-5.1
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
GPT-5.1 (OpenAI)
o1 Pro (OpenAI)
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Which is cheaper, GPT-5.1 or o1 Pro?▼
What is the context window difference between GPT-5.1 and o1 Pro?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
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