Grok 4.5 vs Claude Sonnet 5: which costs less per call, and what about context?
By TechCompare · Updated · How we check
Grok 4.5 wins on output price and total per-call cost. Pick Sonnet 5 when you need more than 500K context, Anthropic's tool-calling ecosystem, or a deeper cache discount for highly repetitive prompts.
SpaceXAI: Grok 4.5
xAI's own price
- Input
- $2
- Output
- $6
- Cached
- $0.30
per 1M tokens
Price checked 2026-11-12
Anthropic: Claude Sonnet 5
Anthropic's own price
- Input
- $2
- Output
- $10
- Cached
- $0.20
per 1M tokens
Price checked 2026-11-12
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Prices come live from OpenRouter at each maker's own price where it's listed. Temporary deals are left out.
Grok 4.5 and Claude Sonnet 5 sit at the same $2.00 per million input price. Output runs $6 vs $10, and context size splits at 500K vs 1M. The choice for most buyers comes down to output volume and ecosystem lock-in.
Two mid-tier workhorses from different ecosystems. Compare input and output rates side by side.
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)Cached input is text the provider has already processed. It costs less than fresh input. | $0.30 | $0.20 (better on this spec) |
| Batch input / output (per M) | None | $1.00 / $5.00 |
| 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. Above 200,000 tokens of prompt, its rates rise to $4 input and $12 output. 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, so Grok wins the call, helped by an output price about 40% lower. Sonnet 5 counters with double the context window, a deeper prompt caching discount, and Anthropic's tooling maturity.
Verdict
The verdict splits cleanly by workload: output-heavy live calls go Grok, agentic loops with long context and repetitive prompts go Sonnet. Grok wins the output row at $6.00/M against $10.00, about 40% lower. A 100K input + 10K output call costs $0.26 on Grok versus $0.30 on Sonnet. Sonnet counters on cache ($0.20/M versus $0.30/M), Sonnet has batch prices ($1.00/$5.00) where Grok has none, and context favors Sonnet (1M versus 500K).
Which should you pick?
Choose Grok 4.5
Output-heavy workloads under 500K context where the lower output price matters and prompts stay under 200,000 tokens. 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 can outweigh the output premium.