Claude Sonnet 4.6 vs GPT-5.1

Summary of our 12-test suite results (specific scores and ranks from our testing):

• Wins for Claude Sonnet 4.6 (our testing): creative_problem_solving 5 vs 4 (Sonnet tied for 1st of 54), tool_calling 5 vs 4 (Sonnet tied for 1st of 54; GPT-5.1 ranks 18 of 54), safety_calibration 5 vs 2 (Sonnet tied for 1st of 55; GPT-5.1 rank 12 of 55), agentic_planning 5 vs 4 (Sonnet tied for 1st of 54; GPT-5.1 rank 16 of 54). These wins indicate Sonnet is stronger at non-obvious idea generation, selecting/sequence functions accurately, refusing or permitting requests correctly, and goal decomposition/failure recovery — all critical for agentic systems and tool integrations.
• Wins for GPT-5.1 (our testing): constrained_rewriting 4 vs 3 (GPT-5.1 rank 6 of 53 vs Sonnet rank 31 of 53). GPT-5.1 is measurably better when you must compress or strictly reformat text under hard character limits.
• Ties (our testing): structured_output 4/4 (both rank 26 of 54), strategic_analysis 5/5 (both tied for 1st of 54), faithfulness 5/5 (both tied for 1st of 55), classification 4/4 (both tied for 1st of 53), long_context 5/5 (both tied for 1st of 55), persona_consistency 5/5 (both tied for 1st of 53), multilingual 5/5 (both tied for 1st of 55). These ties show parity for JSON/schema adherence, high-level reasoning, staying faithful to source material, handling very long contexts, persona maintenance, and multilingual output.
• External benchmarks (Epoch AI): on SWE-bench Verified (Epoch AI), Claude Sonnet 4.6 scores 75.2% vs GPT-5.1 68.0% — Sonnet ranks 4th of 12 vs GPT-5.1 at 7th, supporting Sonnet’s coding/coding-repair strengths in our tests. On AIME 2025 (Epoch AI), GPT-5.1 scores 88.6% vs Sonnet 85.8% — GPT-5.1 wins the math-olympiad style benchmark.
• Context and modality: Sonnet 4.6 has a larger context_window (1,000,000) vs GPT-5.1 (400,000), which matters for massive-context retrieval tasks; GPT-5.1 supports text+image+file->text modality while Sonnet is text+image->text per the payload. Overall, Sonnet’s measured advantages are concentrated where agentic reliability, tool sequencing, and safety matter; GPT-5.1’s strengths are constrained rewriting, AIME-level math, file modality, and lower cost.

Raw per-1k-token pricing: Claude Sonnet 4.6 charges $3 input + $15 output = $18.00 per 1k tokens; GPT-5.1 charges $1.25 input + $10 output = $11.25 per 1k tokens. At realistic volumes that adds up: for 1M tokens/month (1,000 k-tokens) Sonnet = $18,000/month vs GPT-5.1 = $11,250/month (difference $6,750). At 10M tokens Sonnet = $180,000 vs GPT-5.1 = $112,500 (difference $67,500). At 100M tokens Sonnet = $1,800,000 vs GPT-5.1 = $1,125,000 (difference $675,000). High-volume SaaS products, API-first startups, and any service with sustained multi-million-token usage should care about this gap; teams prioritizing agentic reliability, safety, and best tool-calling performance may justify Sonnet’s higher cost, while cost-sensitive deployments or those requiring the file modality on a budget will favor GPT-5.1.

Choose Claude Sonnet 4.6 if you need best-in-class tool calling, strong safety calibration, agentic planning, long-context handling (1,000,000 token window), and are willing to pay ~ $18/1k tokens for higher reliability in production agents. Choose GPT-5.1 if you need lower cost (~$11.25/1k tokens), stronger constrained rewriting, superior AIME 2025 math score (88.6% vs 85.8%), or the text+image+file->text modality and want to minimize monthly spend.