Piano Fundamentals
Note reading, rhythm, hand position, and playing the keyboard — introduced at a pace that fits a four-year-old and scales up for a twelve-year-old.
Two Apps in One · Ages 4–12
The Circle of Fifths
+ Theory Flashcards.
Bring your musical experience full circle — the interactive wheel and seven levels of Theory Flashcards in one app, with Rainbow Gold Quest included free for the little ones. One subscription unlocks everything. Watch them run, below.
See all three, in about a minute.
These are real screen recordings — no mock-ups, no edits. What you see is what your child opens.
1 · The Circle of Fifths
2 · Theory Flashcards 7 levels
3 · Rainbow Gold Quest Bonus
What kids learn
Core piano skills and the theory that makes music make sense — taught through interactive apps kids actually want to open.
Music Theory
Keys, scales, and how chords relate — taught visually through the Circle of Fifths so kids can see why music works the way it does.
Ear Training
Interval recognition and pitch matching through Hear the Chord and Find It. Kids build the musical ear that makes every other skill click faster.
One price. All three apps.
No per-app upsells and no ads. One subscription unlocks the Circle of Fifths, all nine Flash Card modes, and Rainbow Gold Quest — on every device in the house.
Monthly
$9.99/month
Cancel any time.
Start MonthlyYearly
$99.99/year
Works out to $8.33 a month.
Start Yearly- The Circle of Fifths — the full interactive wheel
- Theory Flashcards — nine card groups across seven levels, Student → Maestro
- Rainbow Gold Quest — the kids' game, included free
- Every app we ship next, at no extra cost
Got a 7-day trial code? Redeem it here.
The Circle that shaped music.
The Circle of Fifths arranges all 12 major and minor keys by perfect fifths — a map of every key signature and how the keys relate. Its roots reach back to Pythagoras; its modern circular form appeared in the late 1600s with Nikolay Diletsky and was popularized in 1728 by Johann David Heinichen. For three centuries it has guided musicians through key signatures, chord progressions, and modulation — from the theory classroom to the studio, the stage, and the screen.
Learn the keys
Key signatures at a glance, relative major and minor pairs, and parallel keys — the foundations of theory, made visible on one wheel.
Write and play
Build natural chord progressions, find smooth modulations to neighboring keys, and transpose any song without losing its shape.
Go further
The same circle jazz players use to navigate key centers, analysts use to decode harmony, and producers use to pick complementary keys.
One circle: a map for understanding music and a toolkit for creating it. Its greatest power appears when it stops being a diagram and becomes something a child can tap, hear, and explore — which is exactly what this app is.
For the student who’s waiting.
Every teacher knows the scene: one child at the piano, and a sibling in the corner on a phone — games, videos, anything but music. Hand that child a tablet instead. While one student plays, the other works through the Circle of Fifths and Theory Flashcards, and when it’s their turn at the keys, the theory is already in their head. One studio subscription covers every student who walks through your door.
Interactive apps, not passive video.
Every concept on 4Piano.org is taught through an app kids interact with — tapping keys on the wheel, naming chords by ear, matching pitches. Because the goal isn't for a child to watch someone else play. The goal is to build the muscles, the ear, and the theory instincts that make a real musician.
The platform grows with your child, and your subscription covers every app we ship next.
See the Apps →
Frequently asked questions
What ages is 4Piano.org for?
4Piano.org is designed for children ages 4 to 12. Rainbow Gold Quest suits ages 4 to 7, while the Circle of Fifths and Theory Flashcards carry a child right through to twelve and beyond.
What do I get for the subscription?
All three apps, on every device in the house: the interactive Circle of Fifths, the Theory Flashcards with seven levels, and Rainbow Gold Quest. Every app we ship next is included at no extra cost. $9.99 a month or $99.99 a year.
Will it be too hard for a young child?
The Theory Flashcards climb seven levels, from Student to Maestro — modeled on the graded method books piano teachers use. Level 1 starts with just five notes; each level unlocks more card groups and deeper pools, and Level 7 opens all 12 key signatures. You pick the level and the app remembers it, so a four-year-old and a twelve-year-old can share one subscription.
What's in the Theory Flashcards?
Nine card groups — Notes, Key Signatures, Name the Chord, Hear the Chord, Major/Minor, Intervals, Scale Degrees, Relative Minor, and Mix, which shuffles everything your level has unlocked. Across the seven levels that's over 1.9 million card combinations, each group with a running streak.
Can I try it before I pay?
Yes. Every preview clip on this site is the real app, unedited. And if you have a 7-day trial code, redeem it on this page and all three apps unlock immediately — no card required.
Do children need a piano at home?
No. The apps use an on-screen keyboard, so kids can start learning immediately. A physical piano or keyboard becomes helpful once they progress to playing full pieces.
Is 4Piano.org a replacement for a piano teacher?
It's a complement, not a replacement. 4Piano.org gives kids daily interactive practice with theory concepts between weekly teacher sessions, and can also stand alone for families exploring music before committing to lessons.
Can I cancel?
Any time, from the link in your receipt. A monthly plan stops at the end of the month you've paid for; nothing renews after you cancel.
Already have access?
Sign in
Enter the email you subscribed with and we'll send a one-tap link. No password to remember.
Redeem a 7-day code
Given a trial code? Enter it with your email and all three apps unlock for 7 days.
Not ready yet?
Leave your email and we'll write when the next app ships. No spam, no drip campaign.