R1 0528 vs GPT-5

Across our 12-test suite, GPT-5 wins structured_output and strategic_analysis while R1 0528 wins safety_calibration; the rest are ties. Specifics from our testing: structured_output — GPT-5 5 vs R1 4 (GPT-5 wins; better JSON/schema compliance in tasks that demand strict format); strategic_analysis — GPT-5 5 vs R1 4 (GPT-5 handles nuanced tradeoffs and numeric reasoning better in our tests). safety_calibration — R1 4 vs GPT-5 2 (R1 refuses harmful requests more reliably in our testing). Ties (identical scores in our testing): constrained_rewriting 4/4, creative_problem_solving 4/4, tool_calling 5/5, faithfulness 5/5, classification 4/4, long_context 5/5, persona_consistency 5/5, agentic_planning 5/5, multilingual 5/5 — meaning both models are comparable on these capabilities in practice. External benchmarks (Epoch AI): on MATH Level 5 GPT-5 scores 98.1% (rank 1 of 14) vs R1 96.6% (rank 5 of 14); on AIME 2025 GPT-5 91.4% (rank 6 of 23) vs R1 66.4% (rank 16 of 23); on SWE-bench Verified GPT-5 scores 73.6% (rank 6 of 12) — R1 has no SWE-bench entry in the payload. Note practical quirks: R1’s metadata flags empty responses on structured_output and a requirement for large min/max completion tokens — this can break tight JSON-output pipelines even though its structured_output score is 4 in our testing.

R1 0528 is materially cheaper: input $0.50/mkTok and output $2.15/mkTok vs GPT-5 at $1.25/mkTok input and $10/mkTok output. Output-only costs: 1M tokens → R1 $2,150 vs GPT-5 $10,000; 10M → R1 $21,500 vs GPT-5 $100,000; 100M → R1 $215,000 vs GPT-5 $1,000,000. If you bill both input and output equally, add input: for 1M in+out tokens R1 ≈ $2,650 vs GPT-5 ≈ $11,250. High-volume apps (10M+ tokens/month), consumer chatbots, and low-margin products should care: R1 cuts monthly token bills to ~21.5% of GPT-5 (priceRatio 0.215).

Choose R1 0528 if: you need a high-quality, long-context LLM with strong safety calibration and very low per-token cost — ideal for high-volume chatbots, safety-sensitive moderation, or cost-constrained deployments. Choose GPT-5 if: you need the best structured_output and strategic analysis performance, stronger competition-level math and coding signals (98.1% on MATH Level 5, 91.4% on AIME 2025 per Epoch AI), or the broadest modality support and maximum accuracy for strict JSON/schema tasks.