Claude 3.5 Sonnet vs GPT-5.1
Claude 3.5 Sonnet vs GPT-5.1: GPT-5.1 is cheaper for input-heavy usage ($1.25/M vs $3.00/M input tokens), while GPT-5.1 is better for long-context tasks (1,000,000 tokens).
Direct answer: choose GPT-5.1 for lower token spend and choose GPT-5.1 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 3.5 Sonnet
GPT-5.1
Cost Differences
GPT-5.1 costs less than Claude 3.5 Sonnet
Quick Recommendation
Winner for direct API pricing: GPT-5.1. At the default workload, GPT-5.1 saves about $12.75/month ($155.125/year) versus Claude 3.5 Sonnet.
Feature Comparison
| Feature | Claude 3.5 Sonnet | GPT-5.1 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input Price | $3.00/1M tokens | $1.25/1M tokens |
| Output Price | $15.00/1M tokens | $10.00/1M tokens |
| Context Window | 200,000 tokens | 1,000,000 tokens |
| Max Output | 8,192 tokens | 131,072 tokens |
| Category | balanced | flagship |
| Capabilities | textvisioncode | textvisionaudiocodereasoning |
| Release Date | 10/22/2024 | 11/12/2025 |
Claude 3.5 Sonnet vs GPT-5.1: Which Should You Choose?
Choosing between Claude 3.5 Sonnet and GPT-5.1 depends on your priorities: cost efficiency, context length, or raw capability. GPT-5.1 is the more affordable option at $1.25/1M input tokens — 58% cheaper than Claude 3.5 Sonnet. Meanwhile, GPT-5.1 offers a significantly larger context window at 1,000,000 tokens vs 200,000 for Claude 3.5 Sonnet.
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 3.5 Sonnet is a balanced model while GPT-5.1 is flagship. This means they're optimized for different workloads. GPT-5.1 targets more demanding workloads, while Claude 3.5 Sonnet provides a cost-effective option for everyday tasks.
Output costs matter too. Claude 3.5 Sonnet charges $15.00/1M output tokens vs $10.00 for GPT-5.1. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. GPT-5.1 has the edge here at $10.00/1M output tokens.
Multimodal capabilities: Both models support vision (image understanding), so you can send images alongside text prompts with either option.
Best Use Cases
Choose Claude 3.5 Sonnet when:
- • You're already using Anthropic's API ecosystem
Choose GPT-5.1 when:
- • Budget is a primary concern
- • You need a larger context window (1,000,000 tokens)
- • You need more capabilities (audio, reasoning)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Pros and Caveats at a Glance
Claude 3.5 Sonnet
- • Input pricing: $3.00/M tokens
- • Output pricing: $15.00/M tokens
- • Context window: 200,000 tokens
- • Max output: 8,192 tokens
Watch out for
- • Higher input cost than GPT-5.1
- • Higher output cost than GPT-5.1
- • Smaller context window than GPT-5.1
GPT-5.1
- • Input pricing: $1.25/M tokens
- • Output pricing: $10.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 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 3.5 Sonnet (Anthropic)
GPT-5.1 (OpenAI)
Start using Claude 3.5 Sonnet today
Sign Up for Anthropic →Start using GPT-5.1 today
Sign Up for OpenAI →Frequently Asked Questions
Which is cheaper, Claude 3.5 Sonnet or GPT-5.1?▼
What is the context window difference between Claude 3.5 Sonnet and GPT-5.1?▼
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?▼
Related Comparisons
Related Articles
Learn when to pick each model, then compare live pricing scenarios.