Decimal vs Binary
SI · base 1000 — used by drive makers, macOS and networking. 1 KB = 1000 B.
IEC · base 1024 — used by Windows, RAM and many tools. 1 KiB = 1024 B.
Bytes per unit
Unit
SI (1000)
IEC (1024)
B11
K1,0001,024
M1,000,0001,048,576
G1,000,000,0001,073,741,824
T10¹²1,099,511,627,776
On the main screen: Step sets how much +/− change the value, Unit picks the source unit, and Base toggles SI / IEC.