The Complete Guide to Weight Conversions

Consider this the master page for weight conversions. Below you'll find every supported unit explained, the precise factors connecting them, and computed tables you can rely on for homework, work or travel.

Prefer a calculator? Every conversion on this page has an instant, free tool — start at the tools hub or use the links under each unit below.

The units at a glance

Milligram (mg)

The milligram — one thousandth of a gram — is the unit of medicine dosages and nutrition labels, where tiny quantities matter enormously.

• 1 mg = 0.001 grams (g) — Milligram to Gram converter
• 1 mg = 0.000001 kilograms (kg) — Milligram to Kilogram converter
• 1 mg = 0 metric tons (t) — Milligram to Metric ton converter
• 1 mg = 0.00003527 ounces (oz) — Milligram to Ounce converter
• 1 mg = 0.0000022 pounds (lb) — Milligram to Pound converter
• 1 mg = 0.00000016 stones (st) — Milligram to Stone converter

Gram (g)

The gram is the metric everyday unit for cooking ingredients, letters and jewelry. Originally defined as the mass of a cubic centimeter of water.

• 1 g = 1,000 milligrams (mg) — Gram to Milligram converter
• 1 g = 0.001 kilograms (kg) — Gram to Kilogram converter
• 1 g = 0.000001 metric tons (t) — Gram to Metric ton converter
• 1 g = 0.035274 ounces (oz) — Gram to Ounce converter
• 1 g = 0.002205 pounds (lb) — Gram to Pound converter
• 1 g = 0.00015747 stones (st) — Gram to Stone converter

Kilogram (kg)

The kilogram is the SI base unit of mass, since 2019 defined via the Planck constant rather than a physical metal cylinder in Paris.

• 1 kg = 1,000,000 milligrams (mg) — Kilogram to Milligram converter
• 1 kg = 1,000 grams (g) — Kilogram to Gram converter
• 1 kg = 0.001 metric tons (t) — Kilogram to Metric ton converter
• 1 kg = 35.274 ounces (oz) — Kilogram to Ounce converter
• 1 kg = 2.2046 pounds (lb) — Kilogram to Pound converter
• 1 kg = 0.157473 stones (st) — Kilogram to Stone converter

Metric ton (t)

The metric ton (tonne) equals 1,000 kilograms — the unit of cargo, CO₂ emissions and industrial output.

• 1 t = 1,000,000,000 milligrams (mg) — Metric ton to Milligram converter
• 1 t = 1,000,000 grams (g) — Metric ton to Gram converter
• 1 t = 1,000 kilograms (kg) — Metric ton to Kilogram converter
• 1 t = 35,273.96 ounces (oz) — Metric ton to Ounce converter
• 1 t = 2,204.62 pounds (lb) — Metric ton to Pound converter
• 1 t = 157.473 stones (st) — Metric ton to Stone converter

Ounce (oz)

The avoirdupois ounce is exactly 28.349523125 grams. It dominates American recipe and food-label weights and is one sixteenth of a pound.

• 1 oz = 28,349.52 milligrams (mg) — Ounce to Milligram converter
• 1 oz = 28.3495 grams (g) — Ounce to Gram converter
• 1 oz = 0.02835 kilograms (kg) — Ounce to Kilogram converter
• 1 oz = 0.00002835 metric tons (t) — Ounce to Metric ton converter
• 1 oz = 0.0625 pounds (lb) — Ounce to Pound converter
• 1 oz = 0.004464 stones (st) — Ounce to Stone converter

Pound (lb)

The pound has been defined as exactly 0.45359237 kilograms since 1959. Body weight in the US, gym plates, and package weights all speak in pounds.

• 1 lb = 453,592.37 milligrams (mg) — Pound to Milligram converter
• 1 lb = 453.5924 grams (g) — Pound to Gram converter
• 1 lb = 0.453592 kilograms (kg) — Pound to Kilogram converter
• 1 lb = 0.00045359 metric tons (t) — Pound to Metric ton converter
• 1 lb = 16 ounces (oz) — Pound to Ounce converter
• 1 lb = 0.071429 stones (st) — Pound to Stone converter

Stone (st)

The stone (14 pounds, about 6.35 kg) is the traditional British and Irish unit for body weight — someone might be "11 stone 4" rather than 158 pounds.

• 1 st = 6,350,293.18 milligrams (mg) — Stone to Milligram converter
• 1 st = 6,350.29 grams (g) — Stone to Gram converter
• 1 st = 6.3503 kilograms (kg) — Stone to Kilogram converter
• 1 st = 0.00635 metric tons (t) — Stone to Metric ton converter
• 1 st = 224 ounces (oz) — Stone to Ounce converter
• 1 st = 14 pounds (lb) — Stone to Pound converter

Every conversion formula

The table below lists the exact formula for every weight pair we support. All factors derive from the SI definitions of the units, so chaining them never introduces error.

One-line cross reference: every unit in every other unit

The complete pairwise reference — every supported weight unit expressed in each of the others:

• 1 milligram = 0.001 grams
• 1 milligram = 0.000001 kilograms
• 1 milligram = 0 metric tons
• 1 milligram = 0.00003527 ounces
• 1 milligram = 0.0000022 pounds
• 1 milligram = 0.00000016 stones
• 1 gram = 1,000 milligrams
• 1 gram = 0.001 kilograms
• 1 gram = 0.000001 metric tons
• 1 gram = 0.035274 ounces
• 1 gram = 0.002205 pounds
• 1 gram = 0.00015747 stones
• 1 kilogram = 1,000,000 milligrams
• 1 kilogram = 1,000 grams
• 1 kilogram = 0.001 metric tons
• 1 kilogram = 35.274 ounces
• 1 kilogram = 2.2046 pounds
• 1 kilogram = 0.157473 stones
• 1 metric ton = 1,000,000,000 milligrams
• 1 metric ton = 1,000,000 grams
• 1 metric ton = 1,000 kilograms
• 1 metric ton = 35,273.96 ounces
• 1 metric ton = 2,204.62 pounds
• 1 metric ton = 157.473 stones
• 1 ounce = 28,349.52 milligrams
• 1 ounce = 28.3495 grams
• 1 ounce = 0.02835 kilograms
• 1 ounce = 0.00002835 metric tons
• 1 ounce = 0.0625 pounds
• 1 ounce = 0.004464 stones
• 1 pound = 453,592.37 milligrams
• 1 pound = 453.5924 grams
• 1 pound = 0.453592 kilograms
• 1 pound = 0.00045359 metric tons
• 1 pound = 16 ounces
• 1 pound = 0.071429 stones
• 1 stone = 6,350,293.18 milligrams
• 1 stone = 6,350.29 grams
• 1 stone = 6.3503 kilograms
• 1 stone = 0.00635 metric tons
• 1 stone = 224 ounces
• 1 stone = 14 pounds

Real-world reference points

Useful anchors: a paperclip weighs about a gram, a liter of water exactly one kilogram, a bag of sugar 2.2 pounds (1 kg), an average adult 62 kg globally, and a small car about 1.3 metric tons. When a converted number "feels" wrong against these anchors, double-check your factor.

Most-used conversion tables

Kilogram to Pound

Gram to Ounce

Stone to Pound

Ounce to Pound

Milligram to Gram

Gram to Milligram

Gram to Kilogram

Kilogram to Gram

Common mistakes to avoid

Watch out for the difference between mass and weight in physics contexts, between the avoirdupois ounce (28.35 g) and the troy ounce used for precious metals (31.1 g), and between the US ton (907 kg), UK ton (1,016 kg) and metric ton (1,000 kg) — three different "tons" that are routinely confused.

Tips for accurate conversions

• Round once, at the end. Chaining conversions and rounding each step compounds error surprisingly fast.
• Watch for regional unit variants. Some unit names have US and imperial variants with different sizes — always check which one your source means.
• Estimate first, then compute. A rough mental figure catches order-of-magnitude mistakes before they end up in your work.
• Use exact factors for anything official. The factors in this guide are the internationally defined values, not approximations.

Frequently asked questions

Which weight unit should I use?

Use the unit your audience expects: metric units for international and scientific audiences, US customary units for American everyday contexts. When in doubt, give both — "5 km (3.1 mi)" style.

Are these conversion factors exact?

Yes. Every factor on this page comes from the internationally agreed definition of the units involved (most were fixed by treaty in 1959 or by SI definition), so the only inaccuracy is the rounding you choose for the final answer.

Can I use these tables offline?

Yes — print this page or save it as a PDF. The tables are computed from exact factors and will not go out of date.