> GPT-5.5 Instant is a closed AI model from OpenAI, released 5 May 2026. Index score 136 (GPT-4 = 100), rank 101 of 229 ranked models.

[Models](https://themodelindex.org/models/) /[OpenAI](https://themodelindex.org/labs/openai/)

# GPT-5.5 Instant

OpenAI

Released 5 May 2026

Closed

[Compare](https://themodelindex.org/compare/gpt-5-5-instant-vs-kimi-k2-6/)

136124–148

Index score

#101 · provisional, limited data

2/ 8

Core tests taken

2 of 6 areas · plus 3 anchor tests

−41

Versus the frontier at release

best then: GPT-5.5

–

Price per million tokens

no public API price found

–

Context window

tokens it reads at once

## Where it sits · on the frontier

_Chart: Model Index score of every scored model since late 2022, with the best closed and best open model over time_

Gemini 2.5 Pro reached this score 13 months earlier.

## Test results · by area · tick = best by any model

Show 3 anchor tests

Reasoning & knowledge

evidence

GPQA Diamond

83%

Humanity's Last Exam

no result

Maths

evidence

FrontierMath T1-3

26%

Coding

no evidence yet

SWE-bench Verified

no result

Terminal-Bench

no result

Agents

no evidence yet

APEX-Agents

no result

Novel problems

no evidence yet

ARC-AGI-2

no result

Long tasks

no evidence yet

METR time horizon

no result

Independent results from the Epoch AI benchmarking hub, best reasoning setting. The core tests are shown here; anchor tests also inform the score and can be shown above.

## What others say · rank on each leaderboard

The Model Index

independent tests, our method

#101

of 219 · 136

LMArena · Creative writing

creative writing

#27

of 386 · 1456

LMArena · Text

overall chat quality, judged by people

#36

of 388 · 1473

LMArena · Coding

coding questions in chat

#46

of 383 · 1513

LMArena · Maths

maths questions in chat

#56

of 373 · 1461

Artificial Analysis Intelligence Index

overall capability across ten evaluations

#37

of 207 · 26

LMArena · Vision

understanding images

#28

of 149 · 1276

Epoch Capabilities Index

overall capability from many benchmarks

#94

of 239 · 142.5

LMArena · Documents

working with long documents

#41

of 41 · 1403

Further left is better. Leaderboards measure different things: LMArena is people voting blind between two answers, the others are test scores. Click any row for the source.

## Best at · top three among current models

Not in the top three among current models on any category we track.

Where this model places in the top three of today's models, on category leaderboards and on our core tests.

## Where to use it · prices checked 1 Oct 2026

#### From the lab

ChatGPT

app · subscription

↗

OpenAI API

API

↗

Provider prices come from OpenRouter's live listing; going direct to a provider can differ. Subscriptions are the lab's own apps.

## Facts and sources

Released

5 May 2026

Announcement

not linked yet

Release entry

–

Scored as

GPT-5.5 Instant

Artificial Analysis index

26 · June 2026

Output speed

110 tokens/s

Hugging Face

closed weights

## OpenAI releases · around this one

ChatGPT

Closed

30 NOV 2022

GPT-4

Closed

14 MAR 2023

index 100

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Source: https://themodelindex.org/models/gpt-5-5-instant/ · The Model Index · data as of 2026-10-01