Secondary comparisonPrice Data Last Verified: April 22, 2026

GPT-4.1 vs Grok 4.1 Fast: AI API Cost Comparison (2026)

Grok 4.1 Fast is the safer default for most buyers here. It creates the cleaner cost story, and the savings gap is meaningful enough that you should only move to GPT-4.1 if you have a clear quality reason.

Wins: Standard request costWins: High-volume spendWins: Context window

Standard request winner

Grok 4.1 Fast

Saves about 93% versus the pricier option for the baseline request shape.

Scale winner

Grok 4.1 Fast

Saves about 93% once usage becomes a recurring operating expense.

Default recommendation

Grok 4.1 Fast

Best starting point for most buyers unless you already know you need the premium alternative.

Option A

GPT-4.1

OpenAI

OpenAI1M contextBest for coding & developmentReleased 2025-04
Input
$2.00
Output
$8.00
Context
1M

Best fit

  • Long-context workflows like document review or repo-scale analysis.
  • Developer tooling, code generation, and technical workflows.

Watch-outs

  • Costs compound faster when traffic or output length scales up.

Option B

Grok 4.1 Fast

xAI

Recommended default
xAI256K contextBest for fast responsesReleased 2026-04
Input
$0.20
Output
$0.50
Context
256K

Best fit

  • Teams optimizing for lower blended cost per request.
  • Latency-sensitive product surfaces and user-facing experiences.

Watch-outs

  • You may need to chunk prompts sooner on long-context workloads.
  • Lower price and speed may come with weaker top-end reasoning depth.

Decision scenarios

What we would choose for different teams

This reframes the comparison around real buying situations, not just benchmark curiosity.

Budget-first pick

Choose Grok 4.1 Fast for lower-cost requests

Grok 4.1 Fast wins the standard request scenario, so it is the safer default if you are still validating usage and want cheaper per-call economics.

Scale decision

Choose Grok 4.1 Fast when usage multiplies

Grok 4.1 Fast stays ahead in the high-volume scenario, which matters most once the workload becomes a real operating expense instead of a prototype line item.

Capability-first pick

Choose GPT-4.1 if quality is the main constraint

GPT-4.1 has the stronger capability signal across context, positioning, and premium model attributes. Pick it when reasoning depth or delivery quality matters more than raw token cost.

Decision matrix

Input cost / 1M

Lower is better if prompt volume is the main driver.

Grok 4.1 Fast wins

GPT-4.1

$2.00

Grok 4.1 Fast

$0.20

Output cost / 1M

Lower is better for chat, generation, and verbose outputs.

Grok 4.1 Fast wins

GPT-4.1

$8.00

Grok 4.1 Fast

$0.50

Standard request total

Based on 10,000 input and 10,000 output tokens.

Grok 4.1 Fast wins

GPT-4.1

$0.10

Grok 4.1 Fast

$0.007

Context window

Higher is better when you need fewer prompt-chunking compromises.

GPT-4.1 wins

GPT-4.1

1M

Grok 4.1 Fast

256K

Scenario math

Standard request

10,000 input / 10,000 output tokens

GPT-4.1

$0.10

$0.02 input + $0.08 output

Grok 4.1 Fast

$0.007

$0.002 input + $0.005 output

High-volume scenario

2M input / 2M output tokens

GPT-4.1

$20.00

Grok 4.1 Fast

$1.40

At scale, the cheaper option saves roughly 93% if your workload shape stays similar.

About the methodology

Cost estimates are generated from published input and output token rates for each provider. We apply identical token scenarios to both models so the result reflects pricing differences first, then layer on context and product-positioning signals to make the page more decision-ready. This page should help you narrow the choice quickly, but final selection should still be validated against your own prompts, quality bar, and latency requirements.

Related high-intent comparisons

Go Deeper

Read the model-selection guides behind this comparison