Claude Opus 4.5 vs GPT-5.3 Codex
Claude Opus 4.5 vs GPT-5.3 Codex: GPT-5.3 Codex is cheaper for input-heavy usage ($1.75/M vs $5.00/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)
Claude Opus 4.5
GPT-5.3 Codex
Cost Differences
GPT-5.3 Codex costs less than Claude Opus 4.5
Quick Recommendation
Winner for direct API pricing: GPT-5.3 Codex. At the default workload, GPT-5.3 Codex saves about $26.25/month ($319.375/year) versus Claude Opus 4.5.
Feature Comparison
| Feature | Claude Opus 4.5 | GPT-5.3 Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input Price | $5.00/1M tokens | $1.75/1M tokens |
| Output Price | $25.00/1M tokens | $14.00/1M tokens |
| Context Window | 200,000 tokens | 256,000 tokens |
| Max Output | 64,000 tokens | 32,768 tokens |
| Category | flagship | coding |
| Capabilities | textvisioncodereasoning | textcode |
| Release Date | 11/1/2025 | 3/1/2026 |
Claude Opus 4.5 vs GPT-5.3 Codex: Which Should You Choose?
Choosing between Claude Opus 4.5 and GPT-5.3 Codex 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 — 65% cheaper than Claude Opus 4.5. Meanwhile, GPT-5.3 Codex offers a significantly larger context window at 256,000 tokens vs 200,000 for Claude Opus 4.5.
These models come from different providers — Anthropic and OpenAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with Anthropic, switching to OpenAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Claude Opus 4.5 is a flagship model while GPT-5.3 Codex is coding. This means they're optimized for different workloads. Claude Opus 4.5 is built for complex tasks that require deeper reasoning, while GPT-5.3 Codex offers better value for routine operations.
Output costs matter too. Claude Opus 4.5 charges $25.00/1M 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-5.3 Codex has the edge here at $14.00/1M output tokens.
Multimodal capabilities: Claude Opus 4.5 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 Claude Opus 4.5 when:
- • You need more capabilities (vision, reasoning)
- • You need longer outputs (up to 64,000 tokens)
- • You're already using Anthropic's API ecosystem
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
Pros and Caveats at a Glance
Claude Opus 4.5
- • Input pricing: $5.00/M tokens
- • Output pricing: $25.00/M tokens
- • Context window: 200,000 tokens
- • Max output: 64,000 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
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.
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Claude Opus 4.5 (Anthropic)
GPT-5.3 Codex (OpenAI)
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Sign Up for OpenAI →Frequently Asked Questions
Which is cheaper, Claude Opus 4.5 or GPT-5.3 Codex?▼
What is the context window difference between Claude Opus 4.5 and GPT-5.3 Codex?▼
Which model is better for AI Chatbot?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare Anthropic and OpenAI API pricing beyond this model matchup?▼
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