GPT-5 Nano vs Grok 4

All benchmark claims below reflect our testing across the 12-test suite. Wins, ties, and ranks come from our score and ranking data. Summary of wins/ties: Grok 4 wins 5 tests, GPT-5 Nano wins 3, and 4 tests tie. Detailed walk-through: - Structured output: GPT-5 Nano scores 5 vs Grok 4's 4; GPT-5 Nano ties for 1st in structured output in our rankings ("tied for 1st with 24 other models out of 54 tested"). This means GPT-5 Nano is more reliable for strict JSON/schema compliance. - Safety calibration: GPT-5 Nano 4 vs Grok 4 2; GPT-5 Nano ranks 6th of 55 (tied with 3 others), so it refuses harmful prompts and permits legitimate ones more consistently in our tests. - Agentic planning: GPT-5 Nano 4 vs Grok 4 3; GPT-5 Nano ranks 16 of 54 (tied), indicating stronger goal decomposition and failure recovery behavior for multi-step tasks. - Strategic analysis: Grok 4 scores 5 vs GPT-5 Nano 4; Grok 4 is tied for 1st on strategic analysis ("tied for 1st with 25 other models out of 54 tested"), so it better handles nuanced tradeoffs and numeric reasoning in our scenarios. - Constrained rewriting: Grok 4 4 vs GPT-5 Nano 3; Grok 4 ranks 6 of 53 (shared), showing superior compression into tight character limits. - Faithfulness: Grok 4 5 vs GPT-5 Nano 4; Grok 4 is tied for 1st on faithfulness ("tied for 1st with 32 other models out of 55 tested"), meaning it sticks closer to source material and hallucinates less in our evaluations. - Classification: Grok 4 4 vs GPT-5 Nano 3; Grok 4 ties for 1st in classification ("tied for 1st with 29 other models out of 53 tested"), so routing and labeling tasks favor Grok 4 in our runs. - Persona consistency: Grok 4 5 vs GPT-5 Nano 4; Grok 4 is tied for 1st for maintaining character and resisting prompt injection. - Creative problem solving: tie at 3 — both models produced comparable non-obvious, feasible ideas in our tests. - Tool calling: tie at 4 — both models performed similarly on function selection, argument accuracy, and sequencing; both rank 18 of 54 (shared). - Long context: tie at 5 — both models tied for 1st on 30k+ retrieval accuracy; GPT-5 Nano has a larger context window (400k vs 256k) but both score top in our long-context test. - Multilingual: tie at 5 — both tied for 1st in non-English output quality. External math benchmarks (supplementary): GPT-5 Nano scores 95.2% on MATH Level 5 and 81.1% on AIME 2025 (Epoch AI) — these Epoch AI results suggest GPT-5 Nano is strong on high-level math problems and may benefit math-heavy or symbolic tasks. Overall interpretation: Grok 4 is stronger where faithfulness, classification, persona consistency, constrained rewriting, and strategic analysis matter; GPT-5 Nano is stronger for structured outputs, safety, agentic planning, long context (plus a larger 400k window), and delivers huge cost savings.

Per-1k-token pricing (input+output): GPT-5 Nano = $0.05 + $0.40 = $0.45 per 1k tokens; Grok 4 = $3 + $15 = $18 per 1k tokens. At typical monthly volumes that adds up quickly: for 1M tokens (1,000 k): GPT-5 Nano ≈ $450; Grok 4 ≈ $18,000. For 10M tokens: GPT-5 Nano ≈ $4,500; Grok 4 ≈ $180,000. For 100M tokens: GPT-5 Nano ≈ $45,000; Grok 4 ≈ $1,800,000. The cost gap matters most for product teams, high-volume APIs, and experimentation platforms where millions of tokens are consumed — GPT-5 Nano reduces infrastructure and inference cost by roughly 40x in these comparisons, while Grok 4 remains defensible only when its benchmark wins translate to measurable product value.

Choose GPT-5 Nano if you need extreme cost efficiency, very large context (400k tokens), reliable schema/JSON outputs, stronger safety calibration, or run very high volumes (API products, embedding pipelines, chatbots with heavy token throughput). Choose Grok 4 if your product prioritizes faithfulness, classification accuracy, persona consistency, constrained rewriting, or nuanced strategic analysis and you can justify the higher compute cost for those quality gains.