GPT‑5-Codex vs Grok 4.5
GPT‑5-Codex (OpenAI) and Grok 4.5 (xAI) compared on benchmarks, pricing, context window, and use-case rankings.
- GPT‑5-Codex is cheaper on input tokens — $1.25 vs $2.00 per 1M.
- Grok 4.5 has a larger context window (500K vs 400K tokens).
- Grok 4.5 ranks higher for coding (91th vs 54th percentile).
| Attribute | GPT‑5-Codex | Grok 4.5 |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | — | 154 |
| Coding | 54 | 91 |
| Math | 92 | 85 |
| Reasoning & Knowledge | 60 | 70 |
| Agentic & Tools | 47 | 75 |
| Specifications | ||
| Developer | OpenAI | xAI |
| Family | GPT | Grok |
| Released | Sep 15, 2025 | Jul 8, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | 400K | 500K |
| Price — $/M input | $1.25 | $2.00 |
| Price — $/M output | $10.00 | $6.00 |
| Inputs | text, image | text, image, file |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 99% | 98% |
| APEX | 20% | 34% |
| GPQA Diamond | 84% | 93% |
| Humanity's Last Exam | 26% | 40% |
| LiveCodeBench | 84% | — |
| MMLU-Pro | 87% | — |
| SciCode | 41% | 54% |
| Terminal-Bench | 44% | — |
| WeirdML | 55% | 46% |
| τ²-bench | 87% | — |
| ARC-AGI | — | 87% |
| ARC-AGI-2 | — | 53% |
| SimpleBench | — | 70% |
| SimpleQA Verified | — | 54% |
| WebDev Arena | — | 1551 |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Which is cheaper, GPT‑5-Codex or Grok 4.5?
GPT‑5-Codex is cheaper on input tokens at $1.25 per million, versus $2.00 (representative OpenRouter pricing).
Which has a larger context window, GPT‑5-Codex or Grok 4.5?
Grok 4.5 supports up to 500K tokens, compared with 400K for the other.
Which is better for coding, GPT‑5-Codex or Grok 4.5?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Grok 4.5 ranks higher — 91th vs 54th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.