Comparison · prices as of 2026-08-30 · re-verified 2026-10-05
Claude Haiku 4.5 vs Grok 4 Fast
On price alone, Grok 4 Fast (xAI) runs about 17% cheaper than Claude Haiku 4.5 for a typical chat workload (2K input + 500 output tokens, 1,000 requests/day). Whether that's the right trade depends on the capability gap — the breakdown below shows where each one wins.
Price per million tokens
| Spec | Claude Haiku 4.5 | Grok 4 Fast |
|---|---|---|
| Input / MTok | $1 | $1.25 |
| Output / MTok | $5 | $2.50 |
| Context window | 200K | 2M |
| Max output | 64K | 30K |
| Class | fast / lightweight | fast / lightweight |
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 Haiku 4.5 | Grok 4 Fast | Cheaper |
|---|---|---|---|
| Light — chatbot 0.5K in / 0.2K out · 200 req/day | $9.00 | $6.75 | Grok 4 Fast |
| Typical — assistant 2K in / 0.5K out · 1K req/day | $135 | $113 | Grok 4 Fast |
| Heavy — RAG / agent 8K in / 2K out · 5K req/day | $2,700 | $2,250 | Grok 4 Fast |
Which should you pick?
- Cheapest overall: Grok 4 Fast — about 17% less per month on a typical assistant workload.
- Input-heavy work (long-context RAG, summarization): Claude Haiku 4.5 wins on input at $1/MTok. Output-heavy work (drafting, code generation): Grok 4 Fast wins on output at $2.50/MTok.
- Largest context window: Grok 4 Fast at 2M tokens vs 200K — the one to pick if you feed in whole documents or codebases.
Frequently asked questions
Is Claude Haiku 4.5 or Grok 4 Fast cheaper?
Grok 4 Fast is cheaper — roughly 17% less per month on a typical assistant workload (2K input + 500 output tokens, 1,000 requests/day).
What do Claude Haiku 4.5 and Grok 4 Fast cost per million tokens?
Claude Haiku 4.5 is $1 per million input tokens and $5 per million output. Grok 4 Fast is $1.25 input and $2.50 output. Prices are first-party API list rates as of 2026-08-30.
Which has the larger context window, Claude Haiku 4.5 or Grok 4 Fast?
Grok 4 Fast does, at 2M tokens versus 200K for Claude Haiku 4.5.
When should I choose Claude Haiku 4.5 over Grok 4 Fast?
Both are fast / lightweight-class models, so choose Claude Haiku 4.5 when it measurably wins on your own evals or you prefer its provider (Anthropic); otherwise Grok 4 Fast does the same job for less.
Related comparisons
Sources: Anthropic pricing · xAI pricing. Run your own numbers in the cost calculator.