Weight Mass Unit Converter

Formula or method

Output = input × source mass factor ÷ destination mass factor, using kilograms as the base. One metric tonne = 1,000 kg; one US short ton = 2,000 lb = 907.18474 kg; one Imperial long ton = 2,240 lb = 1,016.0469088 kg. One avoirdupois pound = exactly 0.45359237 kg, and one ounce = 1/16 pound.

How to use this calculator

1. Enter the Value to convert. The interface starts with 1; replace it with your measurement or quantity. Blank, nonnumeric and out-of-range values cannot produce a result.
2. Select From unit for the source unit. Match the complete label, including square/cubic units, decimal/binary prefixes or the gallon system when applicable.
3. Select To unit for the destination unit, then read Converted value with its unit label.
4. Try the worked example with its stated source and destination units. Results show at most eight fractional digits; very small nonzero values use scientific notation. Check the page limitations before interpreting the output.

Worked example

Select US short ton → kilogram (kg) and enter 2: 2 × 907.18474 = 1,814.36948 kg. For 2 Imperial long tons, the result is 2,032.0938176 kg (displayed as 2,032.0938176 kg). Two metric tonnes are 2,000 kg.

Understanding the result

Always retain the full ton label when recording a result: the same number of short tons, long tons and tonnes represents different masses. Everyday “weight” here means mass, not gravitational force.

Limitations and assumptions

• Enter a finite, nonnegative mass, including zero; invalid or out-of-range inputs do not produce a usable result.
• Pounds and ounces are avoirdupois mass, not troy/apothecary units, fluid ounces, pound-force or ton-force.
• No stone, carats or local trade tons are offered. A unit conversion cannot determine volume, density or shipping charges.

Frequently asked questions

Sources

• NIST SP 811: quantity-specific conversion factors
• NIST SP 811 footnote 22: exact avoirdupois pound
• NIST: SI base and derived units