Claude 4 Sonnet vs GPT 5.1 Benchmark: Speed, Cost & Coding Test (2026)

The battle for AI dominance reaches a new high as Anthropic introduces Claude 4 Sonnet to compete head-to-head with OpenAI’s flagship GPT 5.1.

In this comprehensive evaluation, RankLLMs breaks down performance benchmarks across software engineering, reasoning, latency, and pricing.

Quick Verdict

Claude 4 Sonnet wins for software engineering (72.4% SWE-bench), while GPT 5.1 leads on math reasoning & input token cost.

Best for Coding: Claude 4 Sonnet (superior multi-file refactoring & lower hallucination rates).
Best for Math & Logic: GPT 5.1 (95.8% MATH-500 score & $2.50/1M input pricing).
Context Window: Claude 4 Sonnet (200K / 1M beta) vs GPT 5.1 (128K).

Benchmark Highlights

1. SWE-bench Verified (Software Engineering)

Claude 4 Sonnet: 72.4%
GPT 5.1: 70.1%

Claude 4 Sonnet demonstrates superior multi-file refactoring accuracy, fewer hallucinated dependencies, and better comprehension of legacy codebases.

2. Math & Logic Reasoning (MATH-500)

Claude 4 Sonnet: 94.2%
GPT 5.1: 95.8%

GPT 5.1 maintains a tight edge in formal mathematical proofs and symbolic logic calculations.

Token Pricing Comparison

Model	Input (per 1M tokens)	Output (per 1M tokens)	Context Window
Claude 4 Sonnet	$3.00	$15.00	200K (1M beta)
GPT 5.1	$2.50	$10.00	128K

Recommendation

Choose Claude 4 Sonnet for complex codebase refactoring, tool call reliability, and long technical documents.
Choose GPT 5.1 for rapid structured JSON generation, cost optimization on high-volume inputs, and math heavy logic.

Frequently Asked Questions (FAQ)

Which model is better for coding, Claude 4 Sonnet or GPT 5.1?

Claude 4 Sonnet is superior for software engineering and multi-file codebase refactoring, scoring 72.4% on SWE-bench Verified compared to GPT 5.1’s 70.1%.

Is Claude 4 Sonnet more expensive than GPT 5.1?

Yes, Claude 4 Sonnet costs $3.00 per 1M input tokens and $15.00 per 1M output tokens, whereas GPT 5.1 costs $2.50 per 1M input tokens and $10.00 per 1M output tokens.

Which model has a larger context window?

Claude 4 Sonnet supports a 200,000 token context window (with 1 million token extended beta), while GPT 5.1 offers a 128,000 token context window.