GPT-5.3 Codex vs Claude Sonnet 4.6 — Coding AI Comparison 2026

Requests per Day

Days per Month

OpenAI

GPT-5.3 Codex

$0.00

per month

Input cost

Output cost

Cost per request

Requests/month

Anthropic

Claude Sonnet 4.6

$0.00

per month

Input cost

Output cost

Cost per request

Requests/month

Other Models to Consider

GPT-5.3 Codex

OpenAI

$1.75 / $14.00 per 1M

400K context

Claude Sonnet 4.6

Anthropic

$3.00 / $15.00 per 1M

1M context

Claude Opus 4.8

Anthropic

$5.00 / $25.00 per 1M

1M context

Which Model for Which Use Case?

Code Generation at Scale

GPT-5.3 Codex's 42% cheaper input and code-optimized training make it ideal for large-scale code generation pipelines and automated coding assistants.

Better value: GPT-5.3 Codex

Complex Multi-File Refactoring

Claude Sonnet 4.6's 1M context window (2.5x larger than Codex's 400K) handles large-scale refactoring across entire codebases with superior instruction following.

Better context: Claude Sonnet 4.6

Code Review Pipelines

Both models excel at code review. Codex offers better per-token value, while Sonnet provides more thorough analysis with its larger context window.

Better value: GPT-5.3 Codex

Documentation Generation

Claude Sonnet 4.6's superior instruction following and natural language generation make it better for creating comprehensive documentation and code comments.

Better quality: Claude Sonnet 4.6

Comparing Coding Models?

APIpulse lets you compare all 88 models, find the cheapest option for your exact usage, and save scenarios for your team.

88 models across 10 providers

Save up to 10 scenarios

Export PDF cost reports

Optimize — save up to 40%

Free Tools →

Frequently Asked Questions

Is GPT-5.3 Codex cheaper than Claude Sonnet 4.6?

Yes. GPT-5.3 Codex is 42% cheaper on input ($1.75/M vs $3.00/M) and 7% cheaper on output ($14.00/M vs $15.00/M). However, Claude Sonnet 4.6 has 2.5x more context (1M vs 400K).

Which model is better for coding?

Both are top-tier for coding. GPT-5.3 Codex is specifically optimized for code generation tasks, while Claude Sonnet 4.6 excels at instruction following and multi-file refactoring across larger context windows.

When should I choose Claude Sonnet 4.6?

Choose Claude Sonnet 4.6 when you need longer context (1M vs 400K), complex instruction following, multi-file refactoring across large codebases, or documentation generation where nuanced output matters.

Does GPT-5.3 Codex support function calling?

Yes, GPT-5.3 Codex supports full function calling and tool use, making it suitable for agentic coding workflows, automated code review, and CI/CD integration pipelines.