Convert weight or mass between micrograms, milligrams, grams, kilograms, metric carats, metric tonnes, ounces, pounds, stone, short tons, and long tons.
Last updated
Weight and mass converter Convert kilograms, pounds, grams, ounces, stone plus pounds, metric tonnes, US short tons, UK long tons, micrograms, and metric carats from one input.
Input mode
Switching units converts the current mass into the new input format instead of reinterpreting the same digits.
Common examples
Kilograms
70 kg
70 kg equals 70 kg, 154.324 lb, 11 st 0.3 lb, and 2,469.18 oz.
Popular weight conversions
These rows cover the common searches people usually need first: kg to lb, kg to stone and pounds, grams to ounces, pounds to ounces, and tonne-to-ton checks.
Pair
Left side
Right side
Typical use
Kilograms ↔ pounds
70 kg
154.324 lb
Useful for fitness, forms, luggage, and everyday metric-to-US checks.
Kilograms ↔ stone + pounds
70 kg
11 st 0.3 lb
Best for UK and Irish body-weight notation where spoken stone plus pounds is clearer than decimal stone.
Grams ↔ ounces
70,000 g
2,469.18 oz
Useful for recipes, nutrition labels, parcels, and small product weights.
Pounds ↔ ounces
154.324 lb
2,469.18 oz
Use when a scale or shipping label splits a package into pounds and ounces.
Metric tonnes ↔ US/UK tons
0.07 t
0.0772 short ton / 0.0689 long ton
Prevents confusing metric tonnes, US short tons, and UK long tons in freight or bulk-material work.
Micrograms ↔ milligrams
7e+10 mcg
70,000,000 mg
Helpful when reading small mass values in lab, supplement, or technical contexts.
Metric and specialist
Micrograms7e+10 mcg
Milligrams70,000,000 mg
Grams70,000 g
Kilograms70 kg
Metric tonnes0.07 t
Metric carats350,000 ct
Imperial and US customary
Ounces2,469.18 oz
Pounds154.324 lb
Stone11.0231 st
Short tons (US)0.0772 short ton
Long tons (UK)0.0689 long ton
Stone & pounds11 st 0.3 lb
Full conversion sheet notes
Weight is used here in the everyday sense. The calculations convert mass units; fluid ounces and troy ounces are separate systems and are not mixed into this table.
Unit
Value
Typical use
Micrograms
7e+10 mcg
Tiny lab, supplement, and technical mass values.
Milligrams
70,000,000 mg
Small ingredient, supplement, and laboratory weights.
Grams
70,000 g
Cooking, nutrition labels, parcels, and product weights.
Kilograms
70 kg
Body weight, luggage, metric shipping, and SI-based records.
Metric tonnes
0.07 t
Bulk materials, freight, construction, and industrial quantities.
Metric carats
350,000 ct
Metric gemstone mass; not the same as troy ounces.
Ounces
2,469.18 oz
Small US customary weights, recipes, parcels, and groceries.
Pounds
154.324 lb
US body weight, groceries, packages, and everyday scale readings.
Stone
11.0231 st
Decimal stone; UK and Irish body-weight contexts often prefer stone plus pounds.
Short tons (US)
0.0772 short ton
US short tons for freight, materials, and commercial quantities.
Long tons (UK)
0.0689 long ton
UK long tons for older British and maritime contexts.
Stone plus pounds
11 st 0.3 lb
Spoken body-weight notation in the UK and Ireland.
Weight conversion: kilograms, pounds, stone, ounces, and tonnes explained
A weight converter translates any mass or weight value into common metric, imperial, and US customary units simultaneously. This page also explains the main assumptions behind the weight conversion result, highlights the supporting figures shown by the calculator, and helps the reader use the estimate without overstating what a quick online tool can prove.
Metric and imperial weight units compared
The metric system bases all mass units on the kilogram, the SI base unit. One gram is one thousandth of a kilogram; one tonne is one thousand kilograms. Conversion is straightforward multiplication by powers of ten. The imperial and US customary systems use a different set of units: 16 ounces in a pound, 14 pounds in a stone, 2,000 pounds in a US short ton, and 2,240 pounds in a UK long ton.
The fundamental conversion is exact: one pound equals exactly 0.45359237 kg (adopted 1959). From that, one ounce equals 0.028349523125 kg, one stone equals 6.35029318 kg, one US short ton equals 907.18474 kg, and one UK long ton equals 1016.0469088 kg.
The stone-and-pounds composite
In the UK and Ireland, body weight is commonly expressed as a stone-and-pounds composite — for example, "11 stone 4 pounds" rather than "158 lb" or "71.7 kg". One stone equals 14 pounds. To convert a decimal stone value to the composite, take the integer part as whole stones and multiply the remainder by 14 to get the pounds.
This tool handles both directions. Enter a value in any single unit and you get the stone-and-pounds composite alongside all metric values. Or enter stone and pounds separately to get the metric equivalents.
Short tons vs long tons
Two different "tons" are in common use. The short ton (US ton) equals 2,000 pounds or approximately 907 kg — used in the United States for commercial and shipping purposes. The long ton (UK ton) equals 2,240 pounds or approximately 1,016 kg — used historically in the UK and in some international shipping contexts. Both differ from the metric tonne (1,000 kg = 2,205 lb).
When a weight is stated in "tons" without further qualification, context usually determines which is meant: US documents typically use short tons; UK shipping and older British documents often use long tons; scientific and international trade documents use metric tonnes.
Common uses: body weight, cooking, postage, and freight
Body weight: kg worldwide; lb in the US; st and lb in the UK and Ireland. BMI uses weight in kilograms and height in metres — this converter gives you the kg value from any input format. Cooking: recipes may use grams, ounces, or pounds. Postage and parcels: services list maximum weights in kg or lb depending on country.
Freight and bulk materials: metric tonnes are standard internationally; short tons are common in US freight; long tons appear in maritime and bulk shipping. For any of these contexts, enter your known value and unit to see all equivalents at once.
Why the common conversion pairs are shown separately
A broad mass converter can show many units, but most users arrive with a narrower job: kg to lb for body weight or luggage, kg to stone and pounds for a UK-style body-weight reading, grams to ounces for recipes, pounds to ounces for labels, or metric tonnes to US and UK tons for freight. The calculator keeps the full conversion sheet visible while also surfacing those high-intent pairs in a smaller comparison table.
This makes the page more useful than a one-target converter. You can enter 70 kg once and immediately read pounds, stone plus pounds, ounces, grams, and the exact relationships behind them. You can also switch from kilograms to pounds, grams, or stone plus pounds without losing the current mass.
Precision units, carats, and what this converter does not mix
Micrograms and milligrams are included for small mass values such as laboratory notes, supplements, and technical specifications. Metric carats are included for gemstone mass, where 1 carat is exactly 0.2 grams. Those are still mass conversions: the calculator converts through kilograms internally and rounds only for display.
The converter deliberately does not treat fluid ounces as weight units. A fluid ounce is a volume measure, and converting volume to mass requires density. It also does not use troy ounces, which are used for precious metals and differ from the ordinary avoirdupois ounce used for everyday mass. Keeping those systems separate prevents costly unit mistakes.
Rounding and exact constants
The exact constant behind pound-based conversions is 1 lb = 0.45359237 kg. Ounces follow from the exact relationship 16 oz = 1 lb, so one ounce equals 28.349523125 g. Stone follows from 1 st = 14 lb. Short tons and long tons are pound-based: 2,000 lb and 2,240 lb respectively.
For everyday use, a few decimal places are usually enough. For records, labels, invoices, or scientific work, keep the original value and use the level of precision required by the destination system. The calculator uses exact constants internally so a rounded display value does not change the underlying conversion.
1 lb = 0.45359237 kg
Exact international avoirdupois pound relationship.
1 oz = 28.349523125 g
Derived from 16 avoirdupois ounces per pound.
1 st = 14 lb = 6.35029318 kg
Stone and stone-plus-pounds conversion used in UK and Irish body-weight contexts.
1 short ton = 2,000 lb; 1 long ton = 2,240 lb
The two pound-based ton definitions shown separately from the 1,000 kg metric tonne.
1 ct = 0.2 g
The metric carat used for gemstone mass.
Frequently asked questions
How many kilograms are in a pound?
One pound equals exactly 0.45359237 kilograms. Equivalently, one kilogram equals approximately 2.20462 pounds. The factor is exact because the pound was redefined as exactly 0.45359237 kg in 1959 by international agreement.
What is the difference between a metric tonne, a short ton, and a long ton?
A metric tonne = 1,000 kg = 2,204.62 lb. A short ton (US) = 2,000 lb ≈ 907.2 kg. A long ton (UK) = 2,240 lb ≈ 1,016.0 kg. The three are close but not equal — a long ton is about 12% heavier than a short ton, and the metric tonne sits between them.
How do I convert stone and pounds to kilograms?
Multiply the stone value by 14 to get total pounds, then multiply by 0.45359237. For example, 11 st 4 lb = (11 × 14 + 4) = 158 lb × 0.45359237 ≈ 71.67 kg. Alternatively, use this converter — enter your stone and pounds, select "Stone & Pounds" mode, and all metric equivalents are shown instantly.
Is this a weight converter or a mass converter?
In everyday language people search for weight conversions, but the calculator is converting mass units. Weight is technically force under gravity, while kilograms, pounds, grams, ounces, stone, tonnes, and carats are mass units in this context.
Why does the converter show both decimal stone and stone plus pounds?
Decimal stone is mathematically compact, but everyday UK and Irish body-weight notation usually uses whole stones plus remaining pounds, such as 11 st 4 lb. Showing both prevents confusion when a scale, medical form, or conversation uses a different style.
Can I convert ounces to fluid ounces with this tool?
No. Ounces in this converter are avoirdupois mass ounces. Fluid ounces measure volume, not mass, so converting between ounces and fluid ounces requires a density for the specific ingredient or liquid.
Are short tons, long tons, and metric tonnes the same?
No. A metric tonne is 1,000 kg, a US short ton is 2,000 lb, and a UK long ton is 2,240 lb. They are close enough to be confused in freight and bulk-material work, so the calculator labels each one separately.
Why include metric carats in a weight converter?
The metric carat is a mass unit used for gemstones, where 1 ct equals exactly 0.2 g. It is useful for gemstone records, but it should not be confused with karat gold purity or troy ounces used for precious metals.
What rounding should I use for weight conversions?
Use the precision required by the destination. Whole grams or one decimal ounce may be fine for recipes, two decimals may suit labels or invoices, and scientific or lab records may need more precision. The safest workflow is to keep the original value and round only at the final display step.
