Convert mass units like SI, Avoirdupois, Troy, Apothecaries, and others with this one-to-many (O2M) mapping tool. Just input a value and press the Enter key.

When appropriate, conversions follow NIST guidelines (NIST, 2016; 2006).

You may format results according to your needs.

You may also want to follow NIST 2006 guidelines for expressing results to a given number of significant digits:

If the first significant digit of the converted value is greater than or equal to the first significant digit of the original value, round the converted value to the same number of significant digits as there are in the original value.

If the first significant digit of the converted value is smaller than the first significant digit of the original value, round to one more significant digit.