Comparison · prices as of 2026-07-04 · re-verified 2026-08-18
Claude Sonnet 4.5 vs Grok 4
Claude Sonnet 4.5 (Anthropic) and Grok 4 (xAI) price within 0% of each other on a typical chat workload (2K input + 500 output tokens, 1,000 requests/day) — close enough that capability and latency should decide it, not the bill.
Price per million tokens
| Spec | Claude Sonnet 4.5 | Grok 4 |
|---|---|---|
| Input / MTok | $3 | $3 |
| Output / MTok | $15 | $15 |
| Context window | 200K | 256K |
| Max output | 64K | 64K |
| Class | workhorse | frontier |
Estimated monthly cost by workload
Same models, three realistic usage levels. The gap between them scales with volume, so the right pick can change as you grow.
| Workload | Claude Sonnet 4.5 | Grok 4 | Cheaper |
|---|---|---|---|
| Light — chatbot 0.5K in / 0.2K out · 200 req/day | $27.00 | $27.00 | Claude Sonnet 4.5 |
| Typical — assistant 2K in / 0.5K out · 1K req/day | $405 | $405 | Claude Sonnet 4.5 |
| Heavy — RAG / agent 8K in / 2K out · 5K req/day | $8,100 | $8,100 | Claude Sonnet 4.5 |
Which should you pick?
- Price is close to a wash (0% apart on a typical workload), so decide on capability and latency, not cost.
- Claude Sonnet 4.5 is cheaper on both input and output, so it stays cheaper whether your workload is prompt-heavy or generation-heavy.
- Largest context window: Grok 4 at 256K tokens vs 200K — the one to pick if you feed in whole documents or codebases.
- Different classes: Claude Sonnet 4.5 is a workhorse model, Grok 4 is a frontier model — expect Grok 4 to be stronger on hard reasoning and Claude Sonnet 4.5 to be faster and cheaper to run.
Frequently asked questions
Is Claude Sonnet 4.5 or Grok 4 cheaper?
They are close: on a typical assistant workload the difference is only about 0%, with Claude Sonnet 4.5 marginally cheaper.
What do Claude Sonnet 4.5 and Grok 4 cost per million tokens?
Claude Sonnet 4.5 is $3 per million input tokens and $15 per million output. Grok 4 is $3 input and $15 output. Prices are first-party API list rates as of 2026-07-04.
Which has the larger context window, Claude Sonnet 4.5 or Grok 4?
Grok 4 does, at 256K tokens versus 200K for Claude Sonnet 4.5.
When should I choose Grok 4 over Claude Sonnet 4.5?
Choose Grok 4 when you need the extra capability of its frontier class; drop to Claude Sonnet 4.5 when speed and cost matter more than peak quality.
Related comparisons
Sources: Anthropic pricing · xAI pricing. Run your own numbers in the cost calculator.