Finger binary is a system for counting and displaying binary numbers on the fingers of either or both hands. Each finger represents one binary digit or bit. This allows counting from zero to 31 using the fingers of one hand, or 1023 using both: that is, up to 25−1 or 210−1 respectively.
Modern computers typically store values as some whole number of 8-bit bytes, making the fingers of both hands together equivalent to 1¼ bytes of storage—in contrast to less than half a byte when using ten fingers to count up to 10.