Side-by-side technical and economic comparison between OpenAI's OpenAI o3-pro and xAI's Grok 2.
• Grok 2: Classified as a Legacy Reference model (Generally Available).
| Metric | OpenAI o3-pro | Grok 2 | Advantage |
|---|---|---|---|
| Provider Organization | OpenAI | xAI | — |
| Standard Input / 1M | $20.00 | $2.00 | Grok 2 (90% lower) |
| Cached Input / 1M | None | None | Grok 2 lower |
| Output / 1M | $80.00 | $10.00 | Grok 2 lower |
| Context Window | 256k | 128k | OpenAI o3-pro (256k) |
| Max Generation Tokens | 100k | 8.2k | OpenAI o3-pro |
| Tokenizer Family | OpenAI o200k_base (200k vocabulary) | xAI Byte-level BPE (~131k vocabulary) | — |
Opt for OpenAI o3-pro when your engineering requirements prioritize OpenAI's ecosystem, specific tokenizer efficiencies (Exact BPE (o200k_base)), or when your expected prompt-to-completion ratios favor its $20/M input rate.
Opt for Grok 2 when looking for xAI's tooling integration, specific context window depth (128k tokens), or when output generation volume favors its $10/M rate.