Codex Mini vs GPT-5.1

Compare OpenAI and OpenAI AI models

OpenAI

Codex Mini

OpenAI

GPT-5.1

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

Codex Mini

Per Request:$0.004500

Daily:$0.45

Monthly:$13.50

Yearly:$164.25

GPT-5.1

Per Request:$0.006250

Daily:$0.625

Monthly:$18.75

Yearly:$228.125

Cost Differences

+$0.001750

Per Request

+$0.175

Daily

+$5.25

Monthly

+$63.875

Yearly

GPT-5.1 costs more than Codex Mini

Feature Comparison

Feature	Codex Mini	GPT-5.1
Provider	OpenAI	OpenAI
Input Price	$1.50/1M tokens	$1.25/1M tokens
Output Price	$6.00/1M tokens	$10.00/1M tokens
Context Window	200,000 tokens	1,000,000 tokens
Max Output	32,768 tokens	131,072 tokens
Category	efficient	flagship
Capabilities	textcodereasoning	textvisionaudiocodereasoning
Release Date	2/2/2026	11/12/2025

Codex Mini vs GPT-5.1: Which Should You Choose?

Choosing between Codex Mini and GPT-5.1 depends on your priorities: cost efficiency, context length, or raw capability. Codex Mini is the more affordable option at $1.50/1M input tokens. Meanwhile, GPT-5.1 offers a significantly larger context window at 1,000,000 tokens vs 200,000 for Codex Mini.

These models target different tiers: Codex Mini is a efficient model while GPT-5.1 is flagship. This means they're optimized for different workloads. GPT-5.1 targets more demanding workloads, while Codex Mini provides a cost-effective option for everyday tasks.

Output costs matter too. Codex Mini charges $6.00/1M output tokens vs $10.00 for GPT-5.1. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Codex Mini has the edge here at $6.00/1M output tokens.

Multimodal capabilities: GPT-5.1 supports vision (image inputs) while Codex Mini is text-only. If your application needs image understanding, this narrows your choice.

Best Use Cases

Choose Codex Mini when:

• You're already using OpenAI's API ecosystem
• You're running high-volume, latency-sensitive workloads

Choose GPT-5.1 when:

• Budget is a primary concern
• You need a larger context window (1,000,000 tokens)
• You need more capabilities (vision, audio)
• You need longer outputs (up to 131,072 tokens)
• You're already using OpenAI's API ecosystem

Try Different Scenarios

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

Codex Mini (OpenAI)

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GPT-5.1 (OpenAI)

Cost Calculator

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Frequently Asked Questions

Which is cheaper, Codex Mini or GPT-5.1?▼

Codex Mini is cheaper for input tokens at $1.50 per million tokens vs $1.25 for GPT-5.1.

What is the context window difference between Codex Mini and GPT-5.1?▼

Codex Mini supports 200,000 tokens while GPT-5.1 supports 1,000,000 tokens — a difference of 800,000 tokens in favor of GPT-5.1.

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

Both models support text, code, reasoning. For ai agent / agentic workflows, Codex Mini is the lower-cost option, while GPT-5.1 offers a larger context window (1,000,000 vs 200,000 tokens). Choose Codex Mini for budget sensitivity or GPT-5.1 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, Codex Mini costs about $13.50/month and GPT-5.1 costs about $18.75/month. Overall, Codex Mini has lower combined input + output rates ($1.50 in, $6.00 out) vs GPT-5.1.