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Fold Accordion

by Special Glasses LLC

  • Music
  • Paid
  • Small & simple · 100
View on the App Store
Rating
0.0
0 ratings · UK storefront
Last update
Oct 22, 2026
Version 1.0
Size
19 MB
Category
Music
Tracked since
Oct 24, 2026

Estimated revenue

A model estimate with a likely range, not a reported figure.

No estimate. Apps outside the grossing charts, and some countries, have no reliable rank-to-revenue curve, so we show nothing rather than a guess.

How this estimate is made

Rank: we take the app's best Top Grossing rank on the latest chart day. Category ranks are converted into an equivalent overall rank, because a #10 in Finance earns far less than a #10 overall.

Curve: that equivalent rank is read off a rank-to-revenue curve anchored on public company revenue and market-data reports for the US iPhone App Store.

Country: the curve is scaled per country (Japan is roughly a third of the US, Türkiye under 1%). Where we have no scale, such as China, there is no estimate.

Range: the likely range widens with country, category and chart depth. It is a plausible span, not a statistical confidence interval.

Not included: ads, payments outside the App Store, and any difference between gross sales and what the developer keeps. Low confidence means indirect data; medium means several independent sources agree.

Full method

Screenshots

As shown on the App Store listing.

About this app

Text from the App Store listing.

Fold Accordion is an accordion you play on your iPhone. On iPhone Duo, the hinge is the bellows. Open and close the phone to push air, and press the keys on screen to pick the notes.

On other iPhones, swing the phone side to side to pump the bellows. Or pick Touch, and the air flows while you hold a key.

PLAY

  • Piano keys for the right hand, C4 to G5
  • Bass notes F, C, G, D, A, E and chords FM, CM, GM, Dm, Am, Em for the left hand
  • Play several keys at once
  • Move faster to play louder
  • A quick change of direction dips the air, like a real bellows
  • Pick how you play: Fold, Swing, or Touch

LEARN

  • 24 public-domain songs, from Ode to Joy to Jingle Bells
  • Learn mode lights up the key to play. The song waits until you play it.
  • Start with the melody while the bass plays along. Then turn on Both hands to play the bass and chord buttons too.
  • Or pick Listen, and the song plays itself while the keys light up
  • Auto bellows pumps the air for you, so you can focus on the keys

SOUNDS

  • Seven sounds: Accordion, Button accordion, Italian accordion, Bandoneon, Reed organ, Harmonica, and Reed synth
  • Accordion and Button accordion are recorded from real accordions
  • Pick a sound and it plays a short tune

ALSO

  • Light and dark mode
  • No network, no account

Pay once. No ads. No subscription. No in-app purchases.

Made for iPhone Duo. Works on iPhone with iOS 26 or later.

Rank history

Daily position in the US charts. #1 is at the top.

Best rank
#11
Current rank
#11
Days charting
2 of 7

On the charts today

Small & simple score

How realistic it is for a small team to build something like this.

100/100

Small & simple

  • Developer size100% · 25

    Developer: 1 app on the charts

  • Audience size100% · 20

    Ratings: 0

  • App size100% · 10

    Size: 19 MB

  • Price model100% · 15

    Price model: paid

  • Demand proof100% · 30

    Best rank #1, 15 countries

An indicator, not a fact. We can't see team size. Calculated Oct 25, 2026 · method i2

How the score works

Gap check · UK

Is this US chart app missing in UK?

Already on UK charts

It showed up on a UK chart in the last 30 days, so it is not a gap.

Store not checked yet

This is a candidate, not a verdict. Charts show at most 100 apps, so not charting does not mean no demand. Check the UK store before you decide.

See all gaps

Version history

  • 1.0LatestReleased Oct 22, 2026