Weight converter (kg, lb, stone, oz)

Convert kg to lbs, pounds to kg, stone to kg and ounces to grams with the exact 1959 pound, plus tonnes, carats, troy ounces and tola.

Drafted with AI writing toolsUpdated Checked examples: 4

A number in the “from” unit, or with its own unit
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Converted value
lb
Converted value: 2.20462262185 lb
Significant figures: 12; Nearest, ties away from zero
Conversion
1 kg ≈ 2.204623 lb
Conversion factor
2.20462262185
Exactness
Exact definitions, repeating decimal

1 kg is about 2.204623 lb.

The same amount counted in each unit

kg1 kglb2.204623 lb
1 kg in every Mass unit Rows: 15
UnitValueDefinition
kilogram (kg)1Base unit
gram (g)1,0001 g = 0.001 kg, exact
milligram (mg)1,000,0001 mg = 0.000001 kg, exact
microgram (µg)1,000,000,0001 µg = 1 × 10⁻⁹ kg, exact
tonne (t)0.0011 t = 1,000 kg, exact
quintal (q)0.011 q = 100 kg, exact
pound (lb)2.2046231 lb = 0.45359237 kg, exact
ounce (oz)35.273961 oz = 0.028349523125 kg, exact
stone (st)0.1574731 st = 6.35029318 kg, exact
short ton (ton (US))0.0011023111 ton (US) = 907.18474 kg, exact
long ton (ton (UK))0.00098420651 ton (UK) = 1,016.0469088 kg, exact
carat (ct)5,0001 ct = 0.0002 kg, exact
grain (gr)15,432.361 gr = 0.00006479891 kg, exact
troy ounce (oz t)32.150751 oz t = 0.0311034768 kg, exact
tola85.735321 tola = 0.0116638038 kg, exact (180 grains (Indian standard))
How it's calculated S
  1. Convert kilogram to pound

    1 kg÷0.45359237 kglb=2.20462262185 lb1\ \text{kg} \div 0.45359237\ \tfrac{\text{kg}}{\text{lb}} = 2.20462262185\ \text{lb}

    1 lb = 0.45359237 kg, exact

    Both units are defined exactly, but the converted value is a repeating decimal; it is shown to 12 significant figures.

About the weight converter

Every mass unit is a fixed number of kilograms. The pound has been exactly 0.45359237 kg since the 1959 international yard and pound agreement, so pounds, ounces (1/16 lb), stones (14 lb) and short and long tons all convert exactly. The kilogram itself has been defined since 2019 by a fixed value of the Planck constant.

The default converts 1 kg to 2.20462262185 lb, a repeating decimal shown to 12 significant figures. Body weight is the usual reason to convert: 70 kg is about 154.32 lb, or just over 11 stone.

Weight here means mass, the sense in which scales and shops use the word. Precious metals use the troy ounce (31.1034768 g) rather than the ordinary ounce (28.349523125 g), and gems are weighed in metric carats of exactly 200 mg.

How to convert tons to kilograms

A metric tonne is exactly 1,000 kg, so multiply tonnes by 1,000: 2.5 t = 2,500 kg. Divide by 1,000 to go from kilograms to tonnes: 750 kg = 0.75 t. A US short ton is 907.18474 kg and a UK long ton is 1,016.0469088 kg, so first check which ton a document means.

MeaningKilograms per onePounds per one
Metric tonne (t)1000≈ 2204.62262185
US short ton907.184742000
UK long ton1016.04690882240

The SI Brochure, Table 8 defines the tonne as 1,000 kg. The other two tons are defined in pounds, and the international pound is exactly 0.45359237 kg: 2,000 lb gives 907.18474 kg, and 2,240 lb gives 1,016.0469088 kg.

Which ton does a document mean?

  • t, tonne or metric ton: 1,000 kg.
  • Short ton or US ton: 2,000 lb. In US documents an unqualified "ton" normally means this one.
  • Long ton or UK ton: 2,240 lb, the old British imperial ton.

NIST Appendix B.9 lists the short and long tons separately. The gap is too large to ignore: three short tons of gravel is 2,721.55422 kg, about 278 kg less than three tonnes. A long ton is 1.6% heavier than a tonne.

How to convert any mass unit

Multiply by the source unit's mass in kilograms, then divide by the target unit's mass in kilograms. For 5 lb to grams: 5 × 0.45359237 kg = 2.26796185 kg, which is 2,267.96185 g. For 11 stone: 11 × 6.35029318 = 69.85322498 kg.

The table gives one of each unit in kilograms. Metric units scale by powers of ten, as NIST's SI mass guidance explains; ounces and pounds are avoirdupois.

Unit codeKilograms per unit
kg1
g0.001
mg0.000001
ug0.000000001
t1000
q100
lb0.45359237
oz0.028349523125
st6.35029318
ton_us907.18474
ton_uk1016.0469088
ct0.0002
gr0.00006479891
ozt0.0311034768
tola0.0116638038

Ounces, grains, carats and tolas

  • Ounce (oz): 1/16 lb, 28.349523125 g, or 437.5 grains.
  • Troy ounce (ozt): 480 grains, 31.1034768 g. Gold and silver are priced in troy ounces.
  • Grain (gr): 1/7,000 lb, 64.79891 mg.
  • Carat (ct): 200 mg, so a gram is 5 carats.
  • Quintal (q): 100 kg.
  • Tola: 180 grains, 11.6638038 g.

Common mistakes

  • Treating every ton as 1,000 kg. 20 short tons is 18,143.6948 kg, not 20,000 kg.
  • Weighing gold in ordinary ounces. A troy ounce is about 2.75 g heavier than an ordinary ounce, roughly 9.7% more.
  • Converting fluid ounces as mass. A fluid ounce measures volume. Use the volume converter, and expect the mass to depend on what the liquid is.
  • Mixing mass and force. Kilograms and pounds here measure mass, the everyday sense of weight. Newtons and pounds-force belong in the force converter.

For body weight in stones and pounds alongside height, use the height and weight converter. The single-direction pages lbs to kg and kg to lbs include charts for everyday weights.

Worked examples

1 kg to pounds

Value
1 kg
From
kilogram (kg)
To
pound (lb)
Converted value
2.2046226218 lb
Exactness
Exact definitions, repeating decimal

Checked against: 1 lb = 0.45359237 kg exactly (1959 agreement); 1/0.45359237 = 100000000/45359237

1 stone in pounds

Value
1 st
From
stone (st)
To
pound (lb)
Converted value
14 lb

Checked against: NIST HB 44 App. C: 1 stone = 14 lb

1 ounce in grams

Value
1 oz
From
ounce (oz)
To
gram (g)
Converted value
28.349523125 g
Exactness
Exact

Checked against: 1/16 × 453.59237 g = 28.349523125 g (NIST HB 44 App. C)

1 tola in grams

Value
1 tola
From
tola
To
gram (g)
Converted value
11.6638038 g

Checked against: 1 tola = 180 grains; 1 grain = 64.79891 mg exactly (NIST HB 44 App. C): 180 × 64.79891 mg

Questions

How many pounds are in a kilogram?

About 2.20462262 lb. The pound is defined as exactly 0.45359237 kg, so 1 kg = 1 ÷ 0.45359237 = 2.2046226218… lb, a decimal that never ends. The shortcut “multiply by 2.2” is about 0.2% low: 100 kg is about 220.46 lb, not 220.

How many kilograms are in a stone?

Exactly 6.35029318 kg. A stone is 14 lb, and 14 × 0.45359237 kg gives that figure. Stones are still used for body weight in the UK and Ireland; 11 st 7 lb is 161 lb, or about 73.03 kg. To convert that mixed weight, select pounds and enter 11*14+7.

What is the difference between a troy ounce and an ounce?

A troy ounce is 31.1034768 g and an ordinary (avoirdupois) ounce is 28.349523125 g, so the troy ounce is about 9.7% heavier. Gold, silver and platinum prices are quoted per troy ounce. A troy pound has 12 troy ounces, while the ordinary pound has 16 ounces.

Is a ton the same as a tonne?

No. A tonne (metric ton) is 1,000 kg. A US short ton is 2,000 lb, 907.18474 kg, and a UK long ton is 2,240 lb, 1,016.0469088 kg. The long ton is 12% heavier than the short ton, so shipping and freight documents should state which one they use.

How many grams is a tola?

11.6638038 g. A tola is 180 grains, and a grain is exactly 64.79891 mg (NIST Handbook 44), so 180 × 64.79891 mg = 11.6638038 g. Gold is still traded by the tola in South Asia and the Gulf, where a 10-tola bar weighs about 116.64 g.

About this calculator

1 lb=0.45359237 kg1 oz=116 lb1 st=14 lb1 oz t=31.1034768 g1 ct=200 mg\begin{gathered} 1\ \mathrm{lb} = 0.45359237\ \mathrm{kg} \\ 1\ \mathrm{oz} = \tfrac{1}{16}\ \mathrm{lb} \\ 1\ \mathrm{st} = 14\ \mathrm{lb} \\ 1\ \mathrm{oz\ t} = 31.1034768\ \mathrm{g} \\ 1\ \mathrm{ct} = 200\ \mathrm{mg} \end{gathered}

Sources

  1. NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors
  2. NIST Handbook 44, Appendix C — General tables of units of measurement
  3. BIPM — SI base unit: kilogram

Checked against references

This calculator includes 4 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.

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