> Step 3 is an open-weights AI model from StepFun, released 25 Jul 2025.

[Models](https://themodelindex.org/models/) /[StepFun](https://themodelindex.org/labs/stepfun/)

# Step 3

StepFun

Released 25 Jul 2025

Open

[Compare](https://themodelindex.org/compare/step-3-vs-gpt-5/)

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Index score

Not yet evaluated independently

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Core tests taken

no independent results yet

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Versus the frontier at release

Replaced by [Step 5 Preview](https://themodelindex.org/models/step-5-preview/)

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Price per million tokens

no public API price found

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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_

Not plotted: no index score yet.

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

Reasoning & knowledge

no evidence yet

GPQA Diamond

no result

Humanity's Last Exam

no result

Maths

no evidence yet

FrontierMath T1-3

no result

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

LMArena · Coding

coding questions in chat

#179

of 383 · 1409

LMArena · Maths

maths questions in chat

#179

of 373 · 1362

LMArena · Text

overall chat quality, judged by people

#192

of 388 · 1349

LMArena · Creative writing

creative writing

#195

of 386 · 1311

LMArena · Vision

understanding images

#105

of 149 · 1145

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

Replaced by Step 5 Preview; it no longer leads any category among current models.

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

StepFun platform

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

25 Jul 2025

Announcement

not linked yet

Release entry

Step 3

Scored as

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Artificial Analysis index

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Output speed

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Hugging Face

not linked

## StepFun releases · around this one

Step 3

Open

25 JUL 2025

Step 3.5 Flash

Open

2 FEB 2026

Step 3.7 Flash

Open

29 MAY 2026

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Source: https://themodelindex.org/models/step-3/ · The Model Index · data as of 2026-10-01