The small numbers beside the notes are fingerings: 1 is the thumb, 2 index, 3 middle, 4 ring, 5 little finger. Both hands number the same way, starting at the thumb — so each hand’s 5 is its outermost finger.
This is not the string-instrument system, where 1 is the index finger because the thumb does not stop strings. All ten fingers play keys on a piano, so the numbering starts at the thumb and is symmetrical between the hands.
The right hand in C position: 1 on C, 5 on G, one finger per key.
Number
Finger
1
Thumb
2
Index
3
Middle
4
Ring
5
Little finger
Fingering is not a suggestion; it is part of the structure of the piece. When the score says 3 rather than 2, it is usually because a note two measures later needs that finger free. Choosing your own as you go is how you arrive mid-phrase with no fingers left and conclude the piece is too hard.
Common questions
What are the finger numbers on the piano?
They are the small numbers printed beside notes, telling you which finger presses that key: 1 to 5 from thumb to little finger. They get your hand to the right place before the notes arrive.
Is the thumb 1 in both hands?
Yes. The thumb is 1 and the little finger 5 in the left hand and the right, so the hands mirror each other. In a five-finger position the right thumb sits on the lowest key, the left thumb on the highest.
Which finger plays which piano key?
In a five-finger position each finger takes one key: C D E F G is 1 2 3 4 5 in the right hand and 5 4 3 2 1 in the left. Beyond that, follow the numbers the score gives.