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Unit Conversions · Everyday measurements

Mass and Weight Unit Converter

Convert metric, avoirdupois, stone, and ton units using their defined mass equivalents.

Unit Conversions · Everyday measurements

Convert mass

Private in-browser conversion · common equivalents included

Enter one finite number. This quantity is treated as a magnitude, so the value cannot be negative. Select explicitly labeled units—especially where US, Imperial, decimal, or binary conventions differ. Results stay in this browser.

Conversion result

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Enter valid values to see the result.

Your entries are calculated in this browser and are not submitted to 365CALCS.COM.

Quick guide

How to use this calculator

  1. Enter the value exactly as recorded, then choose its source unit and the unit you need.
  2. Check regional and technical qualifiers in the unit names. US and Imperial gallons, force and mass, absolute temperatures and temperature differences, and decimal and binary data prefixes are deliberately separate.
  3. Use the selected result first, then open the common-equivalents table when you need to compare several standards without re-entering the value.

Calculation method

How the mass and weight unit converter works

The entered mass is converted once to the canonical kilogram basis and then from that basis to the selected output unit.

This converts mass-unit values. Weight as a force depends on local acceleration and belongs in the Force Converter.

Worked example

Mass and Weight Unit example

One international avoirdupois pound equals exactly 0.45359237 kilograms.

source value × source-to-kilogram relationship → canonical kilogram value → destination-unit relationship

Supported inputs

Precision and limits

Unit convention

This converts mass-unit values. Weight as a force depends on local acceleration and belongs in the Force Converter.

Precision

Definitions and exact conventional factors are retained internally where available. Display formatting uses up to 12 significant digits; very large or small results use scientific notation. Do not treat displayed digits as measurement accuracy beyond the source value.

Quantity boundary

This page converts mass. It does not infer a different physical quantity, material property, environmental condition, exchange rate, calendar rule, or regulatory value needed to make a cross-quantity conversion.

Privacy

Entered values and converted results stay in this browser and are not sent to analytics or third parties.

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