Grok 4.5 vs Claude Sonnet 5: same price, shorter context, different ecosystem?
Grok 4.5 wins on output price and total per-call cost. Pick Sonnet 5 when you need >500K context, Anthropic's tool-calling ecosystem, or a deeper cache discount for highly-repetitive prompts.
Two mid-tier workhorses with identical input pricing and very different output prices.
Grok 4.5 and Claude Sonnet 5 sit at the same $2.00 per million input price, but diverge sharply on output ($6 vs $10) and context size (500K vs 1M). The choice for most buyers comes down to output volume and ecosystem lock-in.
By TechCompare · Updated
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Prices are fetched live from OpenRouter and may include temporary promotional discounts not accounted for in our article and comparison figures.
Side-by-side specs
| Spec | Grok 4.5 | Claude Sonnet 5 |
|---|---|---|
| Input Cost (per M) | $2.00 | $2.00 |
| Output Cost (per M) | $6.00 (better on this spec) | $10.00 |
| Cached Input (per M) | $0.30 | $0.20 (better on this spec) |
| Batch Discount | No | 50% (better on this spec) |
| Context Window | 500K | 1M (better on this spec) |
How they differ
Grok 4.5 is priced at $2.00 per million input tokens and $6.00 per million output tokens, with an 85% caching discount ($0.30 per million) and a 500K context window. Claude Sonnet 5 is priced at $2.00 per million input tokens and $10.00 per million output tokens, with a 90% caching discount ($0.20 per million) and a 1M context window plus Anthropic's mature tool-calling ecosystem. For a 100K input + 10K output request, Grok 4.5 costs $0.26 vs Sonnet 5's $0.30 - Grok is 40% cheaper on output and wins the call. Sonnet 5 counters with double the context window, deeper prompt-caching discount, and Anthropic's tooling maturity.
Verdict
Grok wins the output row at $6.00/M against $10.00, a 40% gap that holds at the per-call level: 100K input + 10K output costs $0.26 on Grok versus $0.30 on Sonnet. Sonnet counters hard on cache ($0.20/M versus $0.30/M), batch (50% versus none), and context (1M versus 500K). The verdict splits cleanly by workload: output-heavy live calls go Grok, agentic loops with long context and repetitive prompts go Sonnet.
Which should you pick?
Choose Grok 4.5
Output-heavy workloads under 500K context where the lower per-call cost matters. Grok 4.5's $6/M output vs Sonnet 5's $10/M is real savings at scale.
Choose Claude Sonnet 5
Workloads above 500K context, agentic tasks relying on Anthropic's mature tool-calling, or repetitive prompts where Sonnet 5's 90% cache discount outweighs the output premium.