GPT-5.3 Codex vs o3-pro
GPT-5.3 Codex vs o3-pro: GPT-5.3 Codex is cheaper for input-heavy usage ($1.75/M vs $20.00/M input tokens), while o3-pro is better for long-context tasks (1,000,000 tokens).
Direct answer: choose GPT-5.3 Codex for lower token spend and choose o3-pro 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-5.3 Codex
o3-pro
Cost Differences
o3-pro costs more than GPT-5.3 Codex
Quick Recommendation
Winner for direct API pricing: GPT-5.3 Codex. At the default workload, GPT-5.3 Codex saves about $153.75/month ($1,870.625/year) versus o3-pro.
Feature Comparison
| Feature | GPT-5.3 Codex | o3-pro |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price | $1.75/1M tokens | $20.00/1M tokens |
| Output Price | $14.00/1M tokens | $80.00/1M tokens |
| Context Window | 256,000 tokens | 1,000,000 tokens |
| Max Output | 32,768 tokens | 131,072 tokens |
| Category | coding | reasoning |
| Capabilities | textcode | textreasoningcode |
| Release Date | 3/1/2026 | 6/10/2025 |
GPT-5.3 Codex vs o3-pro: Which Should You Choose?
Choosing between GPT-5.3 Codex and o3-pro depends on your priorities: cost efficiency, context length, or raw capability. GPT-5.3 Codex is the more affordable option at $1.75/1M input tokens — 91% cheaper than o3-pro. Meanwhile, o3-pro 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-5.3 Codex is a coding model while o3-pro is reasoning. This means they're optimized for different workloads. o3-pro targets more demanding workloads, while GPT-5.3 Codex provides a cost-effective option for everyday tasks.
Output costs matter too. GPT-5.3 Codex charges $14.00/1M output tokens vs $80.00 for o3-pro. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. GPT-5.3 Codex has the edge here at $14.00/1M output tokens.
Best Use Cases
Choose GPT-5.3 Codex when:
- • Budget is a primary concern
- • You're already using OpenAI's API ecosystem
Choose o3-pro when:
- • You need a larger context window (1,000,000 tokens)
- • You need more capabilities (reasoning)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Pros and Caveats at a Glance
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
- • Smaller context window than o3-pro
o3-pro
- • Input pricing: $20.00/M tokens
- • Output pricing: $80.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Higher input cost than GPT-5.3 Codex
- • Higher output cost than GPT-5.3 Codex
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
GPT-5.3 Codex (OpenAI)
o3-pro (OpenAI)
Start using GPT-5.3 Codex today
Sign Up for OpenAI →Start using o3-pro today
Sign Up for OpenAI →Frequently Asked Questions
Which is cheaper, GPT-5.3 Codex or o3-pro?▼
What is the context window difference between GPT-5.3 Codex and o3-pro?▼
Which model is better for AI Chatbot?▼
Which model has better overall pricing for heavy usage?▼
Related Comparisons
Related Articles
Learn when to pick each model, then compare live pricing scenarios.