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Grok 3 Fast
xAI
xAI's high-throughput variant of Grok 3 — same intelligence as flagship with faster response times
Input price$5.00 / 1M tokens
Output price$25.00 / 1M tokens
Context window128k tokens
Last updated2026-04-22
Quick calculator
Per request
$0.0175
Daily
$175.00
Monthly
$5,250.00
per month · 30-day estimate
Yearly
$63,875.00
Tips to reduce cost
- →Use prompt caching to reuse repeated system prompts
- →Trim whitespace and reduce verbose instructions
- →Use a smaller model for classification or routing tasks
- →Batch async requests to get 50% discount (OpenAI/Anthropic)
- →Cache identical requests at the application layer
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Compared at your current token settings
About Grok 3 Fast
Grok 3 Fast is a premium large language model from xai, priced at $5/1M input tokens and $25/1M output tokens. It is priced above the market average and best suited for low-latency flagship tasks. The 128k context window handles long documents, extended conversations, and large code files comfortably.
For most production workloads, the cost breakdown is dominated by input tokens (system prompts, context, retrieved documents) rather than output. At this price point, Grok 3 Fast is positioned for use cases where quality justifies the premium over cheaper alternatives.
Frequently Asked Questions
How much does Grok 3 Fast cost per 1,000 tokens?
Grok 3 Fast costs $0.0050 per 1,000 input tokens and $0.0250 per 1,000 output tokens.
What is Grok 3 Fast's context window?
Grok 3 Fast supports a context window of 128k tokens, which is suitable for long documents and multi-turn conversations.
How does Grok 3 Fast compare to GPT-4o on price?
Grok 3 Fast is priced above the market average on input tokens. At $5/1M input vs $2.50/1M for GPT-4o, the cost difference becomes significant at scale — 10,000 requests/day with 1,000 input tokens each costs $1500/month with Grok 3 Fast vs $750/month with GPT-4o.