AceStep.io
Start free
AceStep Logo AceStep.io
Free to start - 2 extensions a day - no credit card required

AI Music Extender
Make any song longer

Upload an MP3 or WAV and extend the intro or the ending. ACE-Step composes new music in the same key, style and BPM - an extended version of your song, seamless, in about 20 seconds.

Your file stays in your browser until you hit Extend.

Free to start - 2 extensions per day - No credit card required

Workflow

How to extend a song with AI

Three steps, no editing skills needed. If it plays, it can grow.

STEP 01

Upload your track

Drop in an MP3 or WAV - or pick any song you've already generated on AceStep from your library.

STEP 02

Choose where & how much

Extend the intro or the outro. Add 30, 60 or 90 seconds - the model reads your song's key, BPM and energy first.

STEP 03

Compare & download

Every run gives you two versions. Pick the seamless one, download it royalty-free, or keep shaping it in the multitrack Studio.

Listen first

Hear a real extension

Original on the left, AI-extended on the right. Spot the join - if you can.

Midnight Study Loop

Lo-fiChill

1:00->7:59
0:000:00
Trailer Rise

CinematicEpic

1:00->3:51
0:000:00
Neon Runner

SynthwaveDriving

1:00->4:58
0:000:00

Heard how seamless an AI extension can sound? Upload your own track, choose an intro or outro, and continue in the Extend workspace →

Under the hood

Why the join sounds seamless

Not a loop, not a crossfade - newly composed music that continues yours.

Transition-aware

The model listens to the last bars of your track and writes the continuation from them - no hard cuts, no obvious seams.

Same key & BPM

Key, tempo and instrumentation are detected before a single note is composed, so the extension stays perfectly in tune and in time.

Intro or outro

Add a lead-in before the first beat, or extend the ending past the last one. The tool extends one direction per pass.

~20 seconds per pass

Each extension renders in about 20 seconds, with two versions to compare - iterate until the arrangement feels right.

Any genre

Lo-fi, cinematic, EDM, rock, orchestral - the extension follows your song's style, not a preset template.

Release-ready output

Download MP3 320kbps on paid plans, plus WAV and Hi-Fi on Pro - royalty-free under your plan's rights.

Made for

What people extend music for

Video creators

Fit the full cut

Your 60-second track, your 3-minute video. Extend the bed instead of awkwardly looping it.

DJs & producers

Room to mix

Add longer intros and outros to tracks so you have clean bars to blend in and out of.

Study & sleep

Long-plays, no loops

Grow a favorite ambient or lo-fi piece into an extended version that never repeats itself.

Games & streams

Background that lasts

Stretch menu themes and stream beds so the music outlasts the session, not the other way round.

Questions

AI Music Extender FAQ

How do I make a song longer with AI?

Upload your track (MP3 or WAV), choose whether to extend the intro or the outro, pick how much time to add, and hit Extend. ACE-Step analyzes the key, tempo and instrumentation, then composes new music that continues your song seamlessly - in about 20 seconds.

Is the AI music extender free?

Yes - it's free to start. Create a free account and you get 2 extensions per day, no credit card required. Paid plans add longer songs, Hi-Fi audio, larger credit allowances and commercial rights.

Can I extend an MP3 or WAV file?

Yes - upload MP3 or WAV files up to 50 MB. Extended versions download as MP3 320kbps on paid plans, with WAV and Hi-Fi on Pro. You can also extend any song you've already generated on ACE-Step directly from your library.

Do I need to sign up to use the music extender?

Yes - extending a track needs a free account, which takes about 10 seconds. You get 2 free extensions per day, no credit card required. Your upload and settings stay on the page while you sign up, and the extension starts automatically right after.

How much can I extend a song?

Add 30, 60 or 90 seconds per pass, or set a custom length - and run multiple passes. Free tracks can grow to 2 minutes total; paid plans support songs up to 4 minutes.

Will the extension match my song's style and key?

Yes. Before composing, the model detects your track's key, BPM, instrumentation and energy, then writes the new section to continue them - so the join sounds like it was always part of the song.

Can I extend the beginning of a song too?

Yes. Choose Intro to add a lead-in before your track, or Outro to extend the ending. Each pass extends one direction at a time.

Can I use extended songs commercially?

Extensions of your own AceStep generations follow your plan's rights - Creator covers social monetization, Pro / Artist adds release to Spotify, Apple Music and more. For uploaded third-party music, make sure you hold rights to the original recording.

Do I need to install anything?

No. The extender runs entirely in your browser, on desktop and mobile - upload, extend, listen and download online. It's a simple alternative to loop-editing a track by hand in a DAW.

What makes ACE-Step's song extender different?

Instead of looping or crossfading, ACE-Step composes genuinely new music that continues your track - same key, same BPM, same energy - and every pass returns two versions to compare. It's free to start, handles vocals and instrumentals alike, and connects straight into the multitrack Studio when you want finer control.

Extend your first song free

Two free extensions a day, rendered in about 20 seconds. No credit card, no installs.

Extend a song now