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Weight Converter

A weight converter for kg to lbs and lbs to kg, grams to ounces, stone to kg and tonnes.

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Runs entirely in your browser. What you enter stays on your device — nothing is sent to a server. Verify it yourself

What is the difference between a ton and a tonne?

A tonne is 1,000 kg. A US short ton is 2,000 lb (about 907 kg) and a UK long ton is 2,240 lb (about 1,016 kg) — a spread wide enough that shipping and commodity contracts always specify which is meant.

Cost
Free, no limits
Upload
None — runs on your device
Sign-up
Not required
Works offline
Yes, once loaded

How to convert kg to lbs

  1. Enter the value

    Type the number into the Value box; the result updates as you type.

  2. Choose the units

    Pick From and To — kilograms and pounds to begin with, or grams, ounces, stone, tonnes or either kind of ton. The swap button between them flips the direction.

  3. Read every unit at once

    The All units table below the result shows the value in every mass unit, from milligrams to UK long tons.

Examples

  • 70 kg154.32 lb · 11 st 0.3 lb

    Stones are still common in the UK for body weight and nowhere else.

  • 1 US ton907.18 kg

    A US short ton, not a metric tonne — the two differ by about 10%.

Key features of the Weight Converter

  • Converts between 10 weight units
  • Converts as you type, in both directions
  • Metric and imperial in the same list
  • Runs entirely in your browser

Supported formats

Units

  • Micrograms
  • Milligrams
  • Grams
  • Kilograms
  • Tonnes
  • Ounces
  • Pounds
  • Stone
  • US tons (short)
  • UK tons (long)

When should you use this?

  • Converting body weight between kilograms, pounds and stones.
  • Reading a recipe written in the other system.
  • Checking a shipping weight against a limit.

Limitations

  • Conversions go through a base unit, so a value converted from one unit to another and back can differ in the last decimal place. That is floating-point arithmetic, not a defect, and it is far below the precision of any real measurement.
  • Results are displayed rounded for readability. If you need a specific number of significant figures, round the displayed value yourself rather than assuming the display is exact.
  • Converting a measurement cannot make it more precise than it was. A length measured to the nearest centimetre is still that precise after conversion, however many decimal places appear.
  • Mass and weight are different quantities in physics. Everything here converts mass; the everyday use of "weight" for it is a convention rather than an error, but it matters in technical contexts.
  • Ton is dangerously ambiguous: a US short ton is 907 kg, a UK long ton is 1,016 kg, and a metric tonne is 1,000 kg. This tool uses the US short ton.

Troubleshooting

The answer disagrees with another converter

Usually a different definition of the same unit name — US versus imperial, or a short versus a long ton. Check which variant each tool means before assuming one is wrong.

The last decimal place changes on a round trip

Conversion factors are not exact in binary floating point. The error is around one part in ten thousand billion, which no physical measurement can detect.

Common mistakes to avoid

  • Assuming a unit name is unambiguous. It very often is not.
  • Rounding partway through a multi-step calculation instead of at the end.
  • Treating a ton and a tonne as the same thing. They differ by roughly 10%, which is a lot when it is a shipment.

Pro tips

Tips for better results

  • US and UK units

    The same unit name can mean two amounts

    Check which system a unit belongs to before trusting it. Several unit names mean different amounts in the US and the UK.

  • Working method

    Write the unit beside every number

    Carry the unit through your working rather than converting at the end. Most unit errors happen when a number is written down without one.

Standards and terms behind the Weight Converter

The named things this tool works with, and the documents that define them.

SI unitsSpecification
The international system of units, maintained by the BIPM, which fixes the metre, kilogram, second and kelvin. Reference: SI units
Imperial and US customary unitsSpecification
Inches, feet, pounds, gallons and Fahrenheit — still standard in the United States and common in the UK.

Also searched as: kg to pounds, stones to kg, ounces to grams.

Mass, not weight

Strictly, these are units of mass. Weight is a force — mass times gravitational acceleration — and would be measured in newtons. In everyday use the two words are interchangeable, and every unit here behaves as mass, which is what a kitchen or bathroom scale is actually reporting.

Two different tons

"Ton" means different things in different places, and the difference is large enough to matter:

  • Tonne (metric ton) — 1,000 kg
  • US ton (short ton) — 2,000 lb, about 907 kg
  • UK ton (long ton) — 2,240 lb, about 1,016 kg

A 10% spread between the two imperial variants is why shipping and commodity contracts always specify which.

Stone

A stone is 14 pounds, about 6.35 kg, and is still the everyday unit for body weight in the UK and Ireland. It is generally quoted with pounds alongside — "11 stone 4" is 11 × 14 + 4 = 158 lb.

Privacy

The Weight Converter runs entirely in your browser. What you enter and the result it produces stay on your own device — nothing is sent anywhere, because nothing needs to be.

You can confirm this rather than take our word for it: open your browser’s developer tools, watch the Network tab, and use the tool. No request carries your input. It also keeps working with the connection off.

Details are in the privacy policy.

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Weight Converter — questions

How do I convert pounds to kg?

Multiply by 0.45359237 — a pound is exactly that many kilograms — so 150 lb is 68.04 kg. For kg to pounds, multiply by 2.20462.

How many pounds are in a kilogram?

One kilogram is about 2.20462 pounds. Conversely, a pound is exactly 0.45359237 kg by definition.

What is the difference between a ton and a tonne?

A tonne is 1,000 kg. A US short ton is 2,000 lb (about 907 kg) and a UK long ton is 2,240 lb (about 1,016 kg) — a spread wide enough that contracts always specify which.

How many pounds are in a stone?

Exactly 14. Stone is still the common unit for body weight in the UK and Ireland, usually quoted with remaining pounds — "11 stone 4" is 158 lb.

Is this measuring mass or weight?

Mass. Weight is technically a force measured in newtons, but in everyday use the words are interchangeable and every unit here behaves as mass — which is what a scale reports.

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