Claude Opus 5 vs Grok 4.5
Both are Flagship-tier models, from Anthropic and xAI respectively. Grok 4.5 is the cheaper choice overall at a 4:1 input:output ratio.
Which is cheaper
Side by side
| Spec | Claude Opus 5 | Grok 4.5 |
|---|---|---|
| Provider | Anthropic | xAI |
| Tier | Flagship | Flagship |
| Context window | 1M | 500K |
| Max output | 128K | — |
| Input $/1M | $5.00 | $2.00 |
| Output $/1M | $25.00 | $6.00 |
| Cache read $/1M | $0.50 | $0.30 |
| Cache write $/1M | $6.25 | — |
| Modalities | text, image | text, image |
Claude Opus 5. 5-minute cache write shown ($6.25 = 1.25x base input); 1-hour cache write is $10/MTok (2x base). Batch API is 50% off ($2.50/$12.50). Context window and max output cross-checked against platform.claude.com/docs/en/about-claude/models/overview.
Grok 4.5. Short-context rate, for prompts under 200K tokens. At 200K and above: $4 input / $12 output, cache read $0.60 per 1M. Same input and output price as Grok 4.6 with a cheaper cache read; the previous flagship, not marked deprecated.
Sources
Claude Opus 5 — verified August 29, 2026
Grok 4.5 — verified August 29, 2026
Full Claude Opus 5 pricing page → · Full Grok 4.5 pricing page →