GPT-5.1 vs GPT-5.3 Codex
GPT-5.1 vs GPT-5.3 Codex: GPT-5.1 is cheaper for input-heavy usage ($1.25/M vs $1.75/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
GPT-5.3 Codex
Cost Differences
GPT-5.3 Codex 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 $7.50/month ($91.25/year) versus GPT-5.3 Codex.
Feature Comparison
| Feature | GPT-5.1 | GPT-5.3 Codex |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price | $1.25/1M tokens | $1.75/1M tokens |
| Output Price | $10.00/1M tokens | $14.00/1M tokens |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Max Output | 131,072 tokens | 32,768 tokens |
| Category | flagship | coding |
| Capabilities | textvisionaudiocodereasoning | textcode |
| Release Date | 11/12/2025 | 3/1/2026 |
GPT-5.1 vs GPT-5.3 Codex: Which Should You Choose?
Choosing between GPT-5.1 and GPT-5.3 Codex 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 — 29% cheaper than GPT-5.3 Codex. Meanwhile, GPT-5.1 offers a significantly larger context window at 1,000,000 tokens vs 256,000 for GPT-5.3 Codex.
These models target different tiers: GPT-5.1 is a flagship model while GPT-5.3 Codex is coding. This means they're optimized for different workloads. GPT-5.1 is built for complex tasks that require deeper reasoning, while GPT-5.3 Codex offers better value for routine operations.
Output costs matter too. GPT-5.1 charges $10.00/1M output tokens vs $14.00 for GPT-5.3 Codex. 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: GPT-5.1 supports vision (image inputs) while GPT-5.3 Codex is text-only. If your application needs image understanding, this narrows your choice.
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 (vision, audio, reasoning)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Choose GPT-5.3 Codex 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.
GPT-5.3 Codex
- • Input pricing: $1.75/M tokens
- • Output pricing: $14.00/M tokens
- • Context window: 256,000 tokens
- • Max output: 32,768 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)
GPT-5.3 Codex (OpenAI)
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