Grok 3 Mini vs Grok 4.1 Fast

For most production use cases (structured data, strategy, multilingual support, long context), Grok 4.1 Fast is the better pick — it wins more benchmarks (5 of 12) and offers a 2M context window and multimodal inputs. Grok 3 Mini is preferable when tool calling accuracy and stricter safety calibration matter (tool calling 5/5; safety 2 vs 1), though it has a slightly higher input price ($0.30 vs $0.20 per mTok).

xai

Grok 3 Mini

Overall
3.92/5Strong

Benchmark Scores

Faithfulness
5/5
Long Context
5/5
Multilingual
4/5
Tool Calling
5/5
Classification
4/5
Agentic Planning
3/5
Structured Output
4/5
Safety Calibration
2/5
Strategic Analysis
3/5
Persona Consistency
5/5
Constrained Rewriting
4/5
Creative Problem Solving
3/5

External Benchmarks

SWE-bench Verified
N/A
MATH Level 5
N/A
AIME 2025
N/A

Pricing

Input

$0.300/MTok

Output

$0.500/MTok

Context Window131K

modelpicker.net

xai

Grok 4.1 Fast

Overall
4.25/5Strong

Benchmark Scores

Faithfulness
5/5
Long Context
5/5
Multilingual
5/5
Tool Calling
4/5
Classification
4/5
Agentic Planning
4/5
Structured Output
5/5
Safety Calibration
1/5
Strategic Analysis
5/5
Persona Consistency
5/5
Constrained Rewriting
4/5
Creative Problem Solving
4/5

External Benchmarks

SWE-bench Verified
N/A
MATH Level 5
N/A
AIME 2025
N/A

Pricing

Input

$0.200/MTok

Output

$0.500/MTok

Context Window2000K

modelpicker.net

Benchmark Analysis

Across our 12-test suite (in our testing) Grok 4.1 Fast wins 5 tests, Grok 3 Mini wins 2, and 5 tests tie.

  • Wins for Grok 4.1 Fast: structured output 5 vs 4 (Grok 4.1 Fast is tied for 1st of 54 on structured output; Grok 3 Mini ranks 26/54). This means Grok 4.1 Fast is likelier to produce correct JSON/schema-compliant outputs for integrations. Strategic_analysis 5 vs 3 (Grok 4.1 Fast tied for 1st; Grok 3 Mini rank 36/54) — better at nuanced tradeoff reasoning and numeric strategy. Creative_problem_solving 4 vs 3 (rank 9 vs 30) — more helpful when you need non-obvious, feasible ideas. Agentic_planning 4 vs 3 (rank 16 vs 42) — stronger at goal decomposition and recovery. Multilingual 5 vs 4 (tied for 1st vs rank 36) — better non-English parity.
  • Wins for Grok 3 Mini: tool calling 5 vs 4 (Grok 3 Mini tied for 1st; Grok 4.1 Fast rank 18/54) — Grok 3 Mini is better at function selection, argument accuracy and sequencing in our tests. Safety_calibration 2 vs 1 (Grok 3 Mini rank 12/55; Grok 4.1 Fast rank 32/55) — Grok 3 Mini refused more harmful prompts while permitting legitimate ones more accurately in our testing.
  • Ties: constrained rewriting (4), faithfulness (5), classification (4), long context (5), persona consistency (5) — both models match on long-context retrieval (Grok 4.1 Fast has a 2M context window vs Grok 3 Mini 131,072 tokens), faithfulness and persona consistency in our suite (both tied for 1st in several of these metrics). Practical implication: pick Grok 4.1 Fast when you need top-ranked structured outputs, strategy, multilingual support, agentic planning and multimodal/huge-context workflows. Pick Grok 3 Mini when precise tool-calling orchestration and stricter safety calibration are primary requirements.
BenchmarkGrok 3 MiniGrok 4.1 Fast
Faithfulness5/55/5
Long Context5/55/5
Multilingual4/55/5
Tool Calling5/54/5
Classification4/54/5
Agentic Planning3/54/5
Structured Output4/55/5
Safety Calibration2/51/5
Strategic Analysis3/55/5
Persona Consistency5/55/5
Constrained Rewriting4/54/5
Creative Problem Solving3/54/5
Summary2 wins5 wins

Pricing Analysis

Both models charge $0.50 per mTok for output. Input costs differ: Grok 3 Mini $0.30/mTok, Grok 4.1 Fast $0.20/mTok. To illustrate (assumes tokens split 50/50 between input and output and 1 mTok = 1,000 tokens):

  • 1M total tokens (500k input + 500k output = 500 mTok input + 500 mTok output): Grok 3 Mini = 500*$0.30 + 500*$0.50 = $400. Grok 4.1 Fast = 500*$0.20 + 500*$0.50 = $350. Delta = $50/month.
  • 10M tokens: Grok 3 Mini = $4,000; Grok 4.1 Fast = $3,500. Delta = $500/month.
  • 100M tokens: Grok 3 Mini = $40,000; Grok 4.1 Fast = $35,000. Delta = $5,000/month. Who should care: high-volume API customers and startups at scale — above ~1M tokens/month the input-cost gap becomes meaningful. Single-user or low-volume projects (<100k tokens/mo) will see negligible monthly differences.

Real-World Cost Comparison

TaskGrok 3 MiniGrok 4.1 Fast
iChat response<$0.001<$0.001
iBlog post$0.0011$0.0011
iDocument batch$0.031$0.029
iPipeline run$0.310$0.290

Bottom Line

Choose Grok 3 Mini if: you need best-in-class tool calling (tool calling 5/5 in our testing), stricter safety calibration, or want the 'thinking traces' that help inspect reasoning. Choose Grok 4.1 Fast if: you need superior structured-output reliability (5/5), strategic analysis (5/5), multilingual parity (5/5), a 2M context window, and multimodal inputs — it wins more benchmarks overall (5 of 12) and is slightly cheaper on input ($0.20 vs $0.30/mTok). High-volume deployments should model the $50 per 1M-token (50/50 split) savings when choosing Grok 4.1 Fast.

How We Test

We test every model against our 12-benchmark suite covering tool calling, agentic planning, creative problem solving, safety calibration, and more. Each test is scored 1–5 by an LLM judge. Read our full methodology.

Frequently Asked Questions