Which one is smaller nano or milli

The unit "nano" is smaller than the unit "milli".

1 milli is equal to 0.001.
1 nano is equal to 0.000000001.

Milli is smaller than nano.

The prefixes nano- (symbol: n) and milli- (symbol: m) are part of the International System of Units (SI) used to denote decimal multiples and submultiples of units.

Nano- represents one billionth (10^-9), which means it is 1,000 times smaller than a milli-.

Milli- represents one thousandth (10^-3), which means it is larger than nano by a factor of 1,000.