A piano's serial number enables you to identify the age of a piano--if you can find the number. There are two basic types of piano: vertical and horizontal. Vertical pianos include spinet, console, studio and upright pianos. Horizontal pianos include grand pianos, semiconcert and ballroom pianos. The serial numbers for both types of pianos have several locations to hide: a little detective work and close inspection of your piano should yield the number.
Open the back panel of the piano. The serial number might be located on the top right or top left of the piano (not the panel you removed).
Look at the very top of the piano, on the left or right sides, for the serial number.
Inspect the area in between the left and center area of the tuning pins. You can also look above the right hand tuning pins for the number.
Check the front of the sound board. The serial number could be located to the far left, front corner, the center, or the right hand corner.
Inspect the area directly above the keyboard, under the lid. Serial numbers are found in several locations in this area.
Look at the area to the right of the central hitch pin. The area where the serial number is likely to be located is on one of the circles in the central area of the plate.