Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
GPT-5.1
o4-mini
Cost Differences
o4-mini costs less than GPT-5.1
Feature Comparison
| Feature | GPT-5.1 | o4-mini |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price | $1.25/1M tokens | $1.10/1M tokens |
| Output Price | $10.00/1M tokens | $4.40/1M tokens |
| Context Window | 1,000,000 tokens | 2,000,000 tokens |
| Max Output | 131,072 tokens | 131,072 tokens |
| Category | flagship | reasoning |
| Capabilities | textvisionaudiocodereasoning | textreasoningcode |
| Release Date | 11/12/2025 | 4/16/2025 |
GPT-5.1 vs o4-mini: Which Should You Choose?
Choosing between GPT-5.1 and o4-mini depends on your priorities: cost efficiency, context length, or raw capability. o4-mini is the more affordable option at $1.10/1M input tokens — 12% cheaper than GPT-5.1. Meanwhile, o4-mini offers a significantly larger context window at 2,000,000 tokens vs 1,000,000 for GPT-5.1.
These models target different tiers: GPT-5.1 is a flagship model while o4-mini is reasoning. This means they're optimized for different workloads. GPT-5.1 is built for complex tasks that require deeper reasoning, while o4-mini offers better value for routine operations.
Output costs matter too. GPT-5.1 charges $10.00/1M output tokens vs $4.40 for o4-mini. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. o4-mini has the edge here at $4.40/1M output tokens.
Multimodal capabilities: GPT-5.1 supports vision (image inputs) while o4-mini is text-only. If your application needs image understanding, this narrows your choice.
Best Use Cases
Choose GPT-5.1 when:
- • You need more capabilities (vision, audio)
- • You're already using OpenAI's API ecosystem
Choose o4-mini when:
- • Budget is a primary concern
- • You need a larger context window (2,000,000 tokens)
- • You're already using OpenAI's API ecosystem
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
GPT-5.1 (OpenAI)
o4-mini (OpenAI)
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