Once you get into thousands of kilograms (think car-size weights), you might switch to metric tons, also known as tonnes. The word tonne is not simply a British spelling of ton, it means a metric ton, which is one thousand kilograms.
http://themetricsystem.info/overviewofunits.htm
A yoctometre; which is one septillianth of a metre (10^-24).
http://www.answers.com/Q/What_is_the_smallest_unit_of_length
Only a masochist would want to compare three-eights inch to nine-sixteenths of an inch. For slightly larger sizes you can use centimeters or stick with millimeters. Distances you can walk would be measured in meters, or kilometers if you really need the exercise.
http://themetricsystem.info/overviewofunits.htm
Learning metric really only requires a few reference points and a way to use them in everyday life. It is up to you which things you want to start with first, whether you want to understand Celsius temperatures, or distances, or weight measures, etc.
http://themetricsystem.info/overviewofunits.htm
The smallest unit of length is a Planck Length. This is the  equivalent of a millionth of a billionth of a billionth of a  billionth of a centimeter. This is too small for t … he human eye to  see without assistance like a microscope. Answered.
http://www.answers.com/Q/What_is_the_smallest_unit_of_length
Contrary to what the name suggests, the string coupling constant is not constant, but depends on the value of a scalar field known as the dilaton. In loop quantum gravity, area is quantized, and the Planck area is, within a factor of 10, the smallest possible area value.
https://en.wikipedia.org/wiki/Planck_length
The word Atom was used many years ago to describe the smallest size anything could be. There have been several changes since then. The smallest unit these days is described as … something so small that no-one can see it no mater how hard they look.
http://www.answers.com/Q/What_is_the_smallest_unit_of_length
In string theory, the Planck length is the order of magnitude of the oscillating strings that form elementary particles, and shorter lengths do not make physical sense. The string scale ls is related to the Planck scale by ℓP = gs ls, where gs is the string coupling constant.
https://en.wikipedia.org/wiki/Planck_length
What are the abbreviations for units for length in smallest to largest? millimeter = mmcentimeter = cmmeter = mkilometer = km actually i believe it is 1. milometer =mi then millimeter, centimeter, meter, and finally kilometer. get your facts rig … ht mam/sir.
http://www.answers.com/Q/What_is_the_smallest_unit_of_length
In physics, the Planck length, denoted ℓP, is a unit of length, equal to 6965161619900000000♠1.616199(97)×10−35 metres. It is a base unit in the system of Planck units, developed by physicist Max Planck. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constant.
https://en.wikipedia.org/wiki/Planck_length
what is the smallest unit of length
The smallest unit of length is the Planck Length. The smallest unit of length is the planck length.