Weight Conversion Calculator
Convert pounds, kilograms, ounces and more without hunting for a chart
Weight and mass conversion FAQ
What’s the difference between mass and weight?
In physics, mass measures how much matter an object has and is usually measured in kilograms (kg). Weight is the force of gravity on that mass and can change slightly with location. In everyday use, people say “weight” when they really mean “mass”, so this calculator treats them as interchangeable, just like most scales and nutrition labels do.
How are pounds, ounces and tons related?
In the common U.S. system:
- 1 pound (lb) = 16 ounces (oz).
- 1 short ton (t, US) = 2,000 lb = 32,000 oz.
The calculator uses those exact relationships along with kilogram equivalents, so you can jump between pounds, ounces, short tons, stones and metric units in one place.
What’s the difference between a metric ton and a long ton?
A metric ton (tonne, t) is exactly 1,000 kg. A long ton (lt) is an older UK/imperial unit of 2,240 lb, which works out to about 1,016 kg. This tool lets you convert between short tons (2,000 lb), long tons, metric tons, kilograms, stones and more without remembering all the numbers.
Where do grams and milligrams fit in for food and medicine?
Grams (g) and milligrams (mg) are the most common small mass units. This calculator uses:
- 1 kg = 1,000 g.
- 1 g = 1,000 mg.
They’re ideal for nutrition labels, supplements, medication doses and baking recipes where precision matters more than in everyday “pounds and ounces” talk.
Why are calories and carats included in a weight converter?
Some tables express weight-equivalent relationships between kilocalories (kcal) and kilograms of body mass, and carats (ct) are a standard mass unit for gemstones (1 ct = 0.2 g). This converter follows your reference table and lets you move between those units and kilograms, grams, pounds and other mass units, while still keeping the core focus on weight.
Is this accurate enough for luggage, gym tracking and shipping?
Yes. Internally everything runs through kilograms with stable conversion factors and then gets rounded for display. That’s more than accurate enough for gym logs, suitcase limits, postage estimates, food portions and product labels. For lab-grade work or legal-for-trade scales, use this tool as a cross-check and rely on your calibrated instrument for the official number.
From ounces on a label to tons of cargo in one line
This weight conversion calculator is built for everyday use and quick checks. You can take a gym number in pounds and see it as kilograms, translate a luggage limit from kilograms back to pounds, scale a baking recipe from ounces into grams, or understand how many stones or tons a large load really is. The result card stays simple with a line like “50 lb = 22.68 kg”.
1. Choose the weight units you care about
The dropdowns cover the units you actually see in real life:
- Pounds (lb) and ounces (oz) for body weight, parcels, gym plates, and many US product labels.
- Short tons (US t), metric tons (t) and long tons (lt) for cargo, freight and large loads.
- Kilograms (kg), grams (g) and milligrams (mg) for nutrition labels, recipes and medication doses.
- Stones (st) for UK-style body weight.
- Kilocalories (kcal) as a mass-equivalent from your reference table.
- Carats (ct) for gemstones and small precious items (1 ct = 0.2 g).
Any pair is allowed: pounds to kilograms, stones to pounds, tons to kilograms, grams to ounces, milligrams to carats, or even calories to kilograms using the provided equivalence.
2. Base-unit method: everything through kilograms
Internally, the calculator turns everything into kilograms first, then into the target unit. Each unit has a fixed factor in kilograms, drawn from your table:
- 1 short ton (US t) ≈ 907.18474 kg.
- 1 lb ≈ 0.453592 kg.
- 1 oz ≈ 0.02835 kg (about 28.35 g).
- 1 metric ton (t) = 1,000 kg.
- 1 kg = 1 kg; 1 g = 0.001 kg; 1 mg = 0.000001 kg.
- 1 stone (st) ≈ 6.350293 kg.
- 1 long ton (lt) ≈ 1,016 kg.
- 1 carat (ct) = 0.2 g = 0.0002 kg.
- 1 kilocalorie (kcal) ≈ 0.0001296 kg (from your equivalence of 1 ton ≈ 7,000,000 kcal).
When you hit Convert, the tool multiplies your input by the “to kilograms” factor, then divides by the target unit’s factor. That keeps everything consistent across pounds, kilos, tons, stones and the special units.
3. Weight relationships at a glance
This table picks out some of the core relationships behind the calculator so you can sanity check results or do quick mental estimates for luggage, parcels, recipes and gym plates.
| Starting Unit | Resulting Unit | Relationship |
|---|---|---|
| Everyday and gym weights | ||
| pound (lb) | ounce (oz) | 1 lb = 16 oz |
| short ton (US t) | pound (lb) | 1 t (US) = 2,000 lb |
| kilogram (kg) | pound (lb) | 1 kg ≈ 2.20462 lb |
| kilogram (kg) | ounce (oz) | 1 kg ≈ 35.274 oz |
| Metric mass units | ||
| kilogram (kg) | gram (g) | 1 kg = 1,000 g |
| gram (g) | milligram (mg) | 1 g = 1,000 mg |
| metric ton (t) | kilogram (kg) | 1 t = 1,000 kg |
| stone (st) | pound (lb) | 1 st = 14 lb |
| Special-purpose units | ||
| carat (ct) | gram (g) | 1 ct = 0.2 g |
| long ton (lt) | pound (lb) | 1 lt = 2,240 lb |
| kilocalorie (kcal) | kilogram (kg) | 1 kcal ≈ 0.0001296 kg (from your reference table) |
4. Reading and using the result
The result card stays short and readable. If you enter 23 and convert from kilograms to pounds, you’ll see a line like “23 kg = 50.71 lb”. That’s enough to check baggage allowance, plate loading at the gym, or whether a product spec fits within a shipping service’s limits. If you convert stones to kilograms or grams to ounces, you get the same simple structure.
Because every unit flows through kilograms with consistent factors, the calculator behaves like a clean, modern conversion table for weight and mass—just faster and easier to scan than flipping through charts.
References and further reading on weight and mass units
These resources explain how the main weight and mass units used here are defined:
- Kilogram — defines the kilogram as the SI base unit of mass and shows how grams, milligrams and tonnes relate.
- Pound (mass) — describes the international avoirdupois pound and its relationship to kilograms and ounces.
- Tonne — explains the metric ton (1,000 kg) and compares it with short and long tons.
- Stone (unit) — covers the stone as a body-weight unit and shows that 1 st = 14 lb ≈ 6.35 kg.
- Carat (mass) — defines the carat as 0.2 g and its use in gemology.
For legal-for-trade scales, shipping contracts or medical dosing, always confirm important limits and values against your official documentation or device manuals before finalising numbers.