Weight Converter

Weight Converter

Convert between milligrams, grams, kilograms, ounces, pounds, stone, US tons, and metric tonnes instantly. Weight conversions come up in a surprisingly wide range of real situations — from figuring out your body weight in kilograms for a European gym membership form, to converting a shipping manifest from pounds to tonnes, to scaling a recipe that lists ingredients in grams when your kitchen scale only reads ounces. This converter handles all of those without rounding errors or lookup tables.

How Weight Conversion Works

All weight units convert through grams as a common base. The formula is: Result = Value x (source unit in grams) / (target unit in grams). The exact gram equivalents for each unit are:

• 1 milligram = 0.001 g
• 1 gram = 1 g
• 1 kilogram = 1,000 g
• 1 ounce (avoirdupois) = 28.3495 g
• 1 pound = 453.592 g (16 ounces)
• 1 stone = 6,350.29 g (14 pounds)
• 1 US short ton = 907,185 g (2,000 lbs)
• 1 metric tonne = 1,000,000 g (1,000 kg)

For example, to convert 185 pounds to kilograms: 185 x 453.592 / 1,000 = 83.91 kg.

Worked Examples

A US athlete flying to Germany for a competition needs to list their body weight in kilograms on an entry form. They weigh 195 lbs. Converting: 195 x 453.592 / 1,000 = 88.45 kg. They round to 88.5 kg for the form. Without the converter, the rough estimate of dividing by 2.2 gives 88.6 kg — close enough here, but the exact figure avoids any weigh-in discrepancy.

A small bakery owner is scaling up a bread recipe that was written for a home kitchen. The original recipe calls for 12 oz of bread flour. The bakery’s commercial scale reads in grams. Converting: 12 x 28.3495 = 340.2 g. They measure 340 g and the dough consistency matches the original batch perfectly, confirming the conversion was accurate.

A freight coordinator is quoting shipping costs for a pallet loaded at 4,400 lbs. The overseas carrier’s rate sheet is priced per metric tonne. Converting: 4,400 x 453.592 / 1,000,000 = 1.996 tonnes — just under 2 tonnes. The coordinator confirms the shipment qualifies for the under-2-tonne rate tier, saving $85 on the quote.

Reference Conversion Table

When to Use This Converter

• Fitness and health tracking — US apps report body weight in pounds, European apps in kilograms; converting consistently keeps your progress logs comparable when switching platforms
• International cooking and baking — UK and European recipes list ingredients in grams; US recipes use ounces and cups; converting to grams first then measuring by weight is the most accurate approach for either
• Freight and logistics — international shipping rates are almost always priced per kilogram or metric tonne; converting from US pounds ensures you are quoted the correct rate tier
• Pharmacy and lab work — drug dosages and reagent quantities are measured in milligrams and micrograms; even a small rounding error at this scale has real consequences
• Precious metals and gemstones — gold, silver, and gems use troy ounces (31.1035 g), not standard avoirdupois ounces (28.3495 g); this converter handles avoirdupois units, so be aware of the distinction when working with metals

Common Mistakes to Avoid

1. Confusing US tons and metric tonnes — a US short ton is 2,000 lbs (907 kg), while a metric tonne is 1,000 kg (2,205 lbs). They are close enough to cause expensive errors in freight and material purchasing. A 10-tonne steel order is 22,046 lbs; a 10-US-ton order is 20,000 lbs — a difference of 1 tonne.
2. Using avoirdupois ounces for precious metals — gold and silver are priced per troy ounce (31.1035 g), which is about 10% heavier than a standard ounce (28.3495 g). Never use this converter for precious metal weight calculations without applying the troy ounce correction.
3. Forgetting that stone is a body weight unit, not a general one — stone is used almost exclusively in the UK and Ireland for reporting human body weight. It is 14 pounds exactly. Applying it to other contexts (like food or freight) will confuse anyone outside of a UK/Irish health context.
4. Rounding grams when accuracy matters in baking — bread and pastry recipes depend on ingredient ratios. Rounding 28.35 g to 28 g per ounce is fine for one ounce, but over a 10-ounce measurement the error accumulates to 3.5 g — enough to affect dough hydration in a high-hydration recipe.

Quick Reference Benchmarks

These five weight anchors cover the vast majority of everyday conversions:

• 1 kg = 2.205 lbs — or just “a kilogram is about 2.2 pounds”
• 1 lb = 453.6 g — or “a pound is about 454 grams”
• 1 oz = 28.35 g — or “an ounce is about 28 grams”
• 1 stone = 14 lbs = 6.35 kg — UK body weight unit
• 1 metric tonne = 1,000 kg = 2,205 lbs — slightly heavier than a US ton (2,000 lbs)

Tips

1. For a quick pounds-to-kilograms estimate, divide by 2.2 — for example, 200 lbs / 2.2 = 90.9 kg; the exact value is 90.72 kg, a difference of under 0.2%
2. To convert kilograms to pounds mentally, double the kg value then add 10% — so 75 kg becomes 150 + 15 = 165 lbs (exact: 165.3 lbs)
3. If you track body weight in stone, multiply by 6.35 to get kilograms directly — no need to convert to pounds first
4. For cooking conversions, a kitchen scale set to grams is more accurate than any volume-to-weight conversion table; density varies by ingredient so weight is always more reliable than cups or tablespoons
5. When shipping internationally, convert your package weight to kilograms and round up to the nearest 0.5 kg before requesting a quote — carriers round up on their end and you want an accurate cost estimate
6. Milligrams matter in supplement and medication contexts: 1,000 mg = 1 g, so a 500 mg capsule is half a gram; always verify you are reading milligrams and not micrograms (1,000 times smaller) on pharmaceutical labels