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GPT-5.1-Codex vs GPT-5.1-Codex-Max

GPT-5.1-Codex

OpenAI

87#26
vs
Signal-by-Signal Comparison
SignalGPT-5.1-CodexDeltaGPT-5.1-Codex-Max
Capabilities
100
--
100
Benchmarks
88
--
88
Pricing
90
--
90
Context window size
80
--
80
Recency
90
-4
93
Output Capacity
85
--
85
Overall Result
0 wins
of 6
1 wins
GPT-5.1-Codex-Max wins 1 of 6 signals

Score History

Score History (21 data points)
GPT-5.1-CodexGPT-5.1-Codex-Max
GPT-5.1-Codex

87.4

current score

Leader

Tied

right now

GPT-5.1-Codex-Max

87.4

current score

LMMarketCap.com
Interactive Price Comparison
100Kcalls/month
1,000tokens (~1,333 chars)
500tokens (~667 chars)

GPT-5.1-Codex

OpenAI

Per request$0.006250
Daily$20.83
Monthly$625.00
Annual$7500.00

GPT-5.1-Codex-Max

OpenAI

Per request$0.006250
Daily$20.83
Monthly$625.00
Annual$7500.00
GPT-5.1-Codex pricing:
Input:$1.25/M tokens
Output:$10.00/M tokens
GPT-5.1-Codex-Max pricing:
Input:$1.25/M tokens
Output:$10.00/M tokens
Tie
GPT-5.1-Codex

OpenAI

87

Composite Score

Tie
GPT-5.1-Codex-Max

OpenAI

87

Composite Score

Signal-by-Signal Comparison
MetricGPT-5.1-CodexGPT-5.1-Codex-MaxWinner
Overall Score
87
87
--
Rank#26#24
GPT-5.1-Codex-Max
Quality Rank#26#24
GPT-5.1-Codex-Max
Adoption Rank#26#24
GPT-5.1-Codex-Max
Parameters------
Context Window400K400K--
Pricing$1.25/$10.00/M$1.25/$10.00/M--
Signal Scores
Capabilities
100
100
GPT-5.1-Codex
Benchmarks
88
88
GPT-5.1-Codex
Pricing
90
90
GPT-5.1-Codex
Context window size
80
80
GPT-5.1-Codex
Recency
90
93
GPT-5.1-Codex-Max
Output Capacity
85
85
GPT-5.1-Codex
Benchmark Head-to-Head(11 benchmarks)
GPT-5.1-Codex: 011 tiesGPT-5.1-Codex-Max: 0
GPT-5.1-Codex
GPT-5.1-Codex-Max
Normalized 0-100%
MMLU
93.2%93.2%
MMLU-Pro
85%85%
GPQA Diamond
86.5%86.5%
MATH-500
93.5%93.5%
HumanEval
96.8%96.8%
SWE-bench Verified
76.5%76.5%
IFEval
92.5%92.5%
BBH
91%91%
Arena Elo
14751475
LiveBench
74%74%
HLE
23.68%23.68%
Benchmark Interpretation

Our score (0-100) is driven by benchmark performance (90%) from Arena Elo ratings, MMLU, GPQA, HumanEval, SWE-bench, and 15+ standardized evaluations. Capabilities and context window serve as tiebreakers (10%). Learn more about our methodology.

GPT-5.1-CodexElite Tier

Scores 87/100 (rank #26), placing it in the top 91% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100
GPT-5.1-Codex-MaxElite Tier

Scores 87/100 (rank #24), placing it in the top 92% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100

With only a 0-point gap, these models are in the same performance tier. The practical difference in output quality is minimal - your choice should depend on pricing, latency requirements, and specific feature needs.

When to Use Each Model

Choose GPT-5.1-Codex when you need:

  • Step-by-step reasoning and chain-of-thought problem solving

Choose GPT-5.1-Codex-Max when you need:

  • Step-by-step reasoning and chain-of-thought problem solving
Cost-Performance Analysis
GPT-5.1-CodexBest Value
Input cost$1.25/M tokens
Output cost$10.00/M tokens
Cost per quality point$0.129
Est. monthly (1M tokens/day)$168.75
GPT-5.1-Codex-Max
Input cost$1.25/M tokens
Output cost$10.00/M tokens
Cost per quality point$0.129
Est. monthly (1M tokens/day)$168.75

Both models are priced similarly, so the decision comes down to quality and features rather than cost.

Latency & Speed
GPT-5.1-CodexFaster
Speed score0/100
GPT-5.1-Codex-Max
Speed score0/100

Both models have comparable response speeds. For most applications, the latency difference is negligible.

When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.

Example Use Cases

Code generation & review

Based on overall model capabilities and architecture for coding tasks like generating functions, debugging, and refactoring

GPT-5.1-Codex

Customer support chatbot

Suitable for user-facing chat with competitive response times. GPT-5.1-Codex also offers lower per-token costs for high-volume support

GPT-5.1-Codex

Long document analysis

Larger context window (400K tokens) can process longer documents, contracts, and research papers in a single pass

GPT-5.1-Codex

Batch data extraction

Lower output pricing ($10.00/M) reduces costs when processing thousands of records daily

GPT-5.1-Codex

Creative writing & content

Higher overall composite score (87/100) correlates with better nuance, coherence, and style in long-form content

GPT-5.1-Codex

Image understanding & OCR

Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly

GPT-5.1-Codex
Which Should You Choose?
Our recommendation:
GPT-5.1-Codex

GPT-5.1-Codex and GPT-5.1-Codex-Max are extremely close in overall performance (only 0 points apart). Your best choice depends entirely on which specific strengths matter most for your use case.

GPT-5.1-Codex
Recommended

by OpenAI

  • Choose for Quality - Marginally better benchmark scores; both are excellent
  • Choose for Cost - 0% lower pricing; better value at scale
  • Choose for Reliability - Higher uptime and faster response speeds
  • Choose for Prototyping - Stronger community support and better developer experience
  • Choose for Production - Wider enterprise adoption and proven at scale

by OpenAI

Consider for specialized use cases.

Capability Comparison
CapabilityGPT-5.1-CodexGPT-5.1-Codex-Max
Vision (Image Input)
Function Calling
Streaming
JSON Mode
Reasoning
Web Search
Image Output
Monthly Cost Calculator
1,000tokens (600 in / 400 out)
100requests/day (3,000/month)

GPT-5.1-Codex

OpenAI

$14.25
estimated monthly cost

GPT-5.1-Codex-Max

OpenAI

$14.25
estimated monthly cost

Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.

Parameters & Context
ParameterGPT-5.1-CodexGPT-5.1-Codex-Max
Context Window400K400K
Max Output Tokens128,000128,000
Open SourceNoNo
CreatedNov 13, 2025Dec 4, 2025
Last updated: 2m ago

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GPT-5.1-Codex vs GPT-5.1-Codex-Max (2026) | LM Market Cap