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HomeWeight & Mass
⚖️

Weight & Mass Converter

156+ conversions · 13 units

Convert weight & mass units instantly with ConvertNow. 156+ free conversions, verified formulas, and reference tables. No signup required.

Welcome to the ConvertNow weight & mass converter hub. Whether you are a student solving homework, a professional completing a project, or a traveller navigating unfamiliar units, our free weight & mass conversion tools give you instant, accurate results backed by internationally verified constants.

⭐ Popular Weight & Mass Conversions

kg → g
Kilogram to Gram
kg → lb
Kilogram to Pound
g → oz
Gram to Ounce
t → kg
Metric Ton to Kilogram
lb → kg
Pound to Kilogram
lb → oz
Pound to Ounce
oz → g
Ounce to Gram
st → kg
Stone to Kilogram

All Weight & Mass Conversions

kgKilogram conversions

kg to gkg to mgkg to μgkg to tkg to lbkg to ozkg to stkg to tonkg to long tonkg to ctkg to troy ozkg to gr

gGram conversions

g to kgg to mgg to μgg to tg to lbg to ozg to stg to tong to long tong to ctg to troy ozg to gr

mgMilligram conversions

mg to kgmg to gmg to μgmg to tmg to lbmg to ozmg to stmg to tonmg to long tonmg to ctmg to troy ozmg to gr

μgMicrogram conversions

μg to kgμg to gμg to mgμg to tμg to lbμg to ozμg to stμg to tonμg to long tonμg to ctμg to troy ozμg to gr

tMetric Ton conversions

t to kgt to gt to mgt to μgt to lbt to ozt to stt to tont to long tont to ctt to troy ozt to gr

lbPound conversions

lb to kglb to glb to mglb to μglb to tlb to ozlb to stlb to tonlb to long tonlb to ctlb to troy ozlb to gr

ozOunce conversions

oz to kgoz to goz to mgoz to μgoz to toz to lboz to stoz to tonoz to long tonoz to ctoz to troy ozoz to gr

stStone conversions

st to kgst to gst to mgst to μgst to tst to lbst to ozst to tonst to long tonst to ctst to troy ozst to gr

tonShort Ton (US) conversions

ton to kgton to gton to mgton to μgton to tton to lbton to ozton to stton to long tonton to ctton to troy ozton to gr

long tonLong Ton (UK) conversions

long ton to kglong ton to glong ton to mglong ton to μglong ton to tlong ton to lblong ton to ozlong ton to stlong ton to tonlong ton to ctlong ton to troy ozlong ton to gr

ctCarat conversions

ct to kgct to gct to mgct to μgct to tct to lbct to ozct to stct to tonct to long tonct to troy ozct to gr

troy ozTroy Ounce conversions

troy oz to kgtroy oz to gtroy oz to mgtroy oz to μgtroy oz to ttroy oz to lbtroy oz to oztroy oz to sttroy oz to tontroy oz to long tontroy oz to cttroy oz to gr

grGrain conversions

gr to kggr to ggr to mggr to μggr to tgr to lbgr to ozgr to stgr to tongr to long tongr to ctgr to troy oz

History of Weight & Mass Measurement

Weight measurement traces back to grain seeds and carob seeds used as balance-scale weights over 5,000 years ago. The Roman libra gave us the pound. In 1795 the gram was defined from a cubic centimetre of water. The kilogram was the last SI base unit tied to a physical artefact — a platinum-iridium cylinder in Sèvres — until 2019, when it was redefined using Planck's constant.

Why Accurate Weight & Mass Conversion Matters

Weight conversions protect health (medication dosing), commerce (shipping costs), and safety (aircraft load limits). A 1 kg mistake in luggage fees can cost travellers; a 0.1 g error in pharmaceutical compounding can be dangerous.

Who Uses Weight & Mass Conversions?

Pharmacists, nutritionists, fitness trainers, logistics managers, jewelers, and home cooks.

Common Weight & Mass Conversion Confusions

Pounds vs kilograms (1 lb ≈ 0.454 kg) and ounces vs grams (1 oz ≈ 28.35 g). Many people estimate 1 kg ≈ 2 lb, which is close enough for luggage but inaccurate for medicine.

Weight & Mass Units Reference Table

UnitSymbolBase EquivalentCommon Use
Kilogramkg1 kgGlobal (SI)
Gramg0.001 kgGlobal
Milligrammg1e-6 kgPharmacy
Metric Tonnet1,000 kgShipping
Poundlb0.4536 kgUS, UK
Ounceoz0.02835 kgUS, UK
Stonest6.350 kgUK, Ireland

Quick Weight & Mass Conversion Reference

Common ValueEquals
1 lb0.454 kg
1 oz28.35 g
1 stone6.35 kg
1 tonne2,205 lb

Weight & Mass Conversion FAQ

What is the difference between mass and weight?

Mass is the amount of matter (kilograms). Weight is the force of gravity on that mass (newtons). On Earth they are proportional and often used interchangeably in everyday language.

How many grams in a pound?

1 pound = 453.59237 grams exactly (by international agreement since 1959).

Why do doctors use kilograms but gyms use pounds?

Medical standards follow the SI system (kilograms). US fitness culture historically adopted pounds. Most modern gyms display both.

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Convert MPG and L/100km for vehicle efficiency

Weight & Mass Units

  • Kilogramkg
  • Gramg
  • Milligrammg
  • Microgramμg
  • Metric Tont
  • Poundlb
  • Ounceoz
  • Stonest
  • Short Ton (US)ton
  • Long Ton (UK)long ton
  • Caratct
  • Troy Ouncetroy oz
  • Graingr

Other Categories

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  • 🌡️Temperature
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