---
title: "Check GPT-5.1 — is it still the one to buy · Undominated.ai"
canonical: https://undominated.ai/check/openai__gpt-5.1/
description: "GPT-5.1: whether anything in this catalogue is both better and cheaper, as of Aug 28, 2026. Unrated stays unrated."
---

# Check GPT-5.1 — is it still the one to buy · Undominated.ai

> GPT-5.1: whether anything in this catalogue is both better and cheaper, as of Aug 28, 2026. Unrated stays unrated.

# Check a model

Name what you are paying for. The plot is the same Pareto field as the frontier page. The answer is a computation on this catalogue, not an opinion. Bookmark the URL.

9 undominated of 134 · Aug 28, 2026

As of Aug 28, 2026, GPT-5.1 is dominated for Balanced on LMArena. Muse Spark 1.1 scores 36.9 higher and costs 42% less, with a covering envelope. 9 of 134 rated, priced standard models are undominated.

 Current model

GPT-5.1

 Balanced

3 tokens in per 1 out

 Balanced Summarise Chat Code gen Agentic
 Monthly spend (USD) Used only to say how many months a named switching cost would take to earn back. Leave blank to skip. Switching cost (USD) 134 rated, priced standard models. Chartreuse is the frontier. Cobalt is the model you named, when it is not on the staircase.

Muse Spark 1.1 is both better and cheaper than GPT-5.1.

 [GPT-5.1](/models/openai__gpt-5.1/)

LMArena Elo

 **

1441.4

Effective $/M · Balanced

 **

$3.44/M

 [Muse Spark 1.1](/models/meta__muse-spark-1.1/)

LMArena Elo

 **

1478.3

Effective $/M · Balanced

 **

$2.00/M

## Envelope-safe replacements

Each row scores at least as high, costs no more, and covers this model’s context, output, modalities, tools, and reasoning. A cheaper narrower model is not listed here.

| Model | LMArena | Effective $/M | You save |
| --- | --- | --- | --- |
| Muse Spark 1.1 | 1478.3 +36.9 | $2.00/M | 42% |
| Grok 4.5 | 1452.3 +10.9 | $3.00/M | 13% |
| Grok 4.6 | 1443.7 +2.3 | $3.00/M | 13% |

## Higher score, lower price, named losses

Not a drop-in. The loss is why these are not a recommendation.

| Model | LMArena | Effective $/M | You give up |
| --- | --- | --- | --- |
| Gemini 3.7 Flash | 1490.2 | $0.750/M | max output |
| Gemini 3.5 Flash | 1482.6 | $3.38/M | max output |
| Qwen3.8 Max | 1481.9 | $3.00/M | file |
| GLM 5.3 | 1476.9 | $2.15/M | image, file |
| Gemini 3.6 Flash | 1476.5 | $1.50/M | max output |

Copy watch URL [Open the frontier](/frontier/)

This page does not mail you. The URL is the watch: same model, same mix, current catalogue.