Grok 4.1 Fast vs o4-mini

Compare xAI and OpenAI AI models

xAI

Grok 4.1 Fast

OpenAI

o4-mini

Try xAI →Try OpenAI →

Cost Comparison (1000 input + 500 output tokens, 100 requests/day)

Grok 4.1 Fast

Per Request:$0.000450

Daily:$0.045

Monthly:$1.35

Yearly:$16.425

o4-mini

Per Request:$0.003300

Daily:$0.33

Monthly:$9.90

Yearly:$120.45

Cost Differences

+$0.002850

Per Request

+$0.285

Daily

+$8.55

Monthly

+$104.025

Yearly

o4-mini costs more than Grok 4.1 Fast

Feature Comparison

Feature	Grok 4.1 Fast	o4-mini
Provider	xAI	OpenAI
Input Price	$0.20/1M tokens	$1.10/1M tokens
Output Price	$0.50/1M tokens	$4.40/1M tokens
Context Window	2,000,000 tokens	2,000,000 tokens
Max Output	131,072 tokens	131,072 tokens
Category	efficient	reasoning
Capabilities	textreasoningcode	textreasoningcode
Release Date	1/15/2026	4/16/2025

Grok 4.1 Fast vs o4-mini: Which Should You Choose?

Choosing between Grok 4.1 Fast and o4-mini depends on your priorities: cost efficiency, context length, or raw capability. Grok 4.1 Fast is the more affordable option at $0.20/1M input tokens — 82% cheaper than o4-mini.

These models come from different providers — xAI and OpenAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with xAI, switching to OpenAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.

These models target different tiers: Grok 4.1 Fast is a efficient model while o4-mini is reasoning. This means they're optimized for different workloads. o4-mini targets more demanding workloads, while Grok 4.1 Fast provides a cost-effective option for everyday tasks.

Output costs matter too. Grok 4.1 Fast charges $0.50/1M output tokens vs $4.40 for o4-mini. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok 4.1 Fast has the edge here at $0.50/1M output tokens.

Best Use Cases

Choose Grok 4.1 Fast when:

• Budget is a primary concern
• You're already using xAI's API ecosystem
• You're running high-volume, latency-sensitive workloads

Choose o4-mini when:

• You're already using OpenAI's API ecosystem

Try Different Scenarios

Use the calculator below to see how costs change with different usage patterns

Grok 4.1 Fast (xAI)

Cost Calculator

Provider

Model

Input Tokens

Output Tokens

Requests/Day

Select a provider and model to see costs

o4-mini (OpenAI)

Cost Calculator

Provider

Model

Input Tokens

Output Tokens

Requests/Day

Select a provider and model to see costs

Start using Grok 4.1 Fast today

Start using o4-mini today

Frequently Asked Questions

Which is cheaper, Grok 4.1 Fast or o4-mini?▼

Grok 4.1 Fast is cheaper for input tokens at $0.20 per million tokens vs $1.10 for o4-mini — that's 82% savings on input costs.

What is the context window difference between Grok 4.1 Fast and o4-mini?▼

Grok 4.1 Fast supports 2,000,000 tokens while o4-mini supports 2,000,000 tokens — a difference of 0 tokens in favor of Grok 4.1 Fast.

Which model is better for AI Agent / Agentic Workflows?▼

Both models support text, code, reasoning. For ai agent / agentic workflows, Grok 4.1 Fast is the lower-cost option, while Grok 4.1 Fast offers a larger context window (2,000,000 vs 2,000,000 tokens). Choose Grok 4.1 Fast for budget sensitivity or Grok 4.1 Fast for longer context tasks.

Which model has better overall pricing for heavy usage?▼

At 100 requests/day with 1,000 input and 500 output tokens each, Grok 4.1 Fast costs about $1.35/month and o4-mini costs about $9.90/month. Overall, Grok 4.1 Fast has lower combined input + output rates ($0.20 in, $0.50 out) vs o4-mini.