GPT vs Claude Cost Comparison: Which API is Cheaper?

Choosing between OpenAI and Anthropic isn't just about intelligence—it is also a major financial decision for your software budget.

If you are running millions of API requests daily, a fraction of a cent per token can quickly scale into thousands of dollars. Here is our direct pricing comparison between the flagship models: GPT-5.5 and Claude Sonnet 4.6, as well as their lightweight partners.

Flagship Model Pricing Comparison

For heavy agentic reasoning, code writing, and analysis, you will likely choose between GPT-5.5 and Claude Sonnet 4.6.

Here are the current raw prices per 1 Million Tokens:

| Model | Input Cost (per 1M) | Output Cost (per 1M) | Cached Input Cost | | :--- | :--- | :--- | :--- | | OpenAI GPT-5.5 | $5 | $30 | $0.5 | | Anthropic Claude Sonnet 4.6 | $3 | $15 | $0.3 |

Key Takeaway:

• Input Tokens: Claude Sonnet 4.6 is currently cheaper for input prompts, charging $3 per million compared to GPT-5.5's $5.
• Output Generation: GPT-5.5 is significantly more expensive for generating outputs, costing $30 per million vs Sonnet's $15. If your application writes massive code blocks or long reports, Claude Sonnet is the clear economic winner.

Lightweight Model Pricing Comparison

If you are running simple classification, summarization, or high-volume tasks, the lightweight models are much more cost-effective.

| Model | Input Cost (per 1M) | Output Cost (per 1M) | Cached Input Cost | | :--- | :--- | :--- | :--- | | OpenAI GPT-5.5 Mini | $0.15 | $0.6 | $0.075 | | Google Gemini 3.1 Flash | $0.35 | $1.05 | $0.0875 |

Both models are incredibly cheap, but GPT-5.5 Mini holds a pricing advantage for massive output generations, charging just $0.6 per million tokens.

The Role of Prompt Caching in Your Costs

If your application relies on long, repetitive prompts (like keeping a large system prompt or importing codebase context files), Prompt Caching is critical.

• GPT-5.5 charges $0.5 per million for cached input.
• Claude Sonnet 4.6 charges $0.3 per million for cached input.

If your code reuses the same prompt context within minutes, your input cost drops by up to 90% using caching, making the price gap between the two platforms almost negligible.

Calculate Your Exact Monthly Costs

Don't guess your monthly API bill. We built an interactive utility that calculates your monthly API expenses across all providers based on your custom traffic volume.

👉 Calculate your monthly API bill with our AI Cost Calculator

Disclaimer: Pricing database was last updated on https://openai.com/api/pricing/ guidelines.