GPT-5.3 Codex vs o3 Deep Research
GPT-5.3 Codex vs o3 Deep Research: GPT-5.3 Codex is cheaper for input-heavy usage ($1.75/M vs $10.00/M input tokens), while GPT-5.3 Codex is better for long-context tasks (256,000 tokens).
Direct answer: choose GPT-5.3 Codex for lower token spend and choose GPT-5.3 Codex 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 Deep Research
Cost Differences
o3 Deep Research 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 $63.75/month ($775.625/year) versus o3 Deep Research.
Feature Comparison
| Feature | GPT-5.3 Codex | o3 Deep Research |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price | $1.75/1M tokens | $10.00/1M tokens |
| Output Price | $14.00/1M tokens | $40.00/1M tokens |
| Context Window | 256,000 tokens | 200,000 tokens |
| Max Output | 32,768 tokens | 32,768 tokens |
| Category | coding | reasoning |
| Capabilities | textcode | textreasoningvisioncode |
| Release Date | 3/1/2026 | 6/26/2025 |
GPT-5.3 Codex vs o3 Deep Research: Which Should You Choose?
Choosing between GPT-5.3 Codex and o3 Deep Research 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 — 83% cheaper than o3 Deep Research. Meanwhile, GPT-5.3 Codex offers a significantly larger context window at 256,000 tokens vs 200,000 for o3 Deep Research.
These models target different tiers: GPT-5.3 Codex is a coding model while o3 Deep Research is reasoning. This means they're optimized for different workloads. o3 Deep Research 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 $40.00 for o3 Deep Research. 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.
Multimodal capabilities: o3 Deep Research 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-5.3 Codex when:
- • Budget is a primary concern
- • You need a larger context window (256,000 tokens)
- • You're already using OpenAI's API ecosystem
Choose o3 Deep Research when:
- • You need more capabilities (reasoning, vision)
- • 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
- • Trade-offs are minor in this matchup.
o3 Deep Research
- • Input pricing: $10.00/M tokens
- • Output pricing: $40.00/M tokens
- • Context window: 200,000 tokens
- • Max output: 32,768 tokens
Watch out for
- • Higher input cost than GPT-5.3 Codex
- • Higher output cost than GPT-5.3 Codex
- • Smaller context window 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 Deep Research (OpenAI)
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