Convert a measured mass between metric and customary units, including a mixed stone-and-pounds or pounds-and-ounces reading.
Choose the scale used by your measurement
For a decimal value, select its unit and the desired result unit. For a scale reading such as 10 st 4 lb, select Stone + pounds and enter each part separately. The result includes both mixed formats, every supported unit, and a small reference table. Smaller-unit inputs may exceed 14 pounds or 16 ounces; the displayed mixed result normalizes them.
Everyday ounces and precious-metal weights
An ordinary avoirdupois pound contains 16 ordinary ounces. A troy pound contains 12 troy ounces, and a troy ounce is heavier than an ordinary ounce. Select the explicitly labeled troy units for precious-metal mass. Metric carats measure mass; gold karats describe purity and are not a conversion unit here. This tool does not calculate a metal price or fine-gold content.
Stone, tons, and weight versus mass
The stone used here is 14 international pounds. A metric tonne is 1,000 kg, a US short ton is 2,000 lb, and an imperial long ton is 2,240 lb. Choose the full unit label before comparing shipping or material quantities.
Everyday “weight” readings usually report mass. Newtons measure force and need a gravitational acceleration to convert to mass, so they are not offered as interchangeable mass units. Fluid ounces measure volume; use a volume converter, or a density calculation when crossing from volume to mass.
Formula
kg = pounds × 0.45359237
pounds = stone × 14 + remaining pounds
ounces = pounds × 16
Examples
A scale in stone
10 st 4 lb is 144 lb, or 65.31730128 kg.
An ounce of gold
1 troy oz is 31.1034768 g; 1 ordinary oz is 28.349523125 g. The labels matter.
Precision and definitions
Calculations retain unrounded values internally. Displayed digits do not increase the accuracy of measurements. NIST unit definitions provide the conversion reference.