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weight-converter

A weight converter translates a mass quantity between metric (grams, kilograms, metric tons) and imperial/US units (ounces, pounds, stones, US tons, UK long tons) with full precision based on the SI-exact pound definition (1 lb = 0.45359237 kg). The ZTools Weight Converter shows side-by-side conversions to all common units, supports composite imperial entries (e.g., "5 st 4 lb" parses correctly), distinguishes between metric tonnes (1000 kg), US short tons (2000 lb), and UK long tons (2240 lb) β€” three different "tons" that catch out the unwary.

Use cases​

Cooking and recipe scaling​

British recipe says "8 oz of butter" β€” that's 227 g. Or scale a recipe by weight to half-portion: 500 g flour β†’ 250 g.

Fitness β€” body weight in different units​

UK weight in stones (e.g., 12 st 6 lb), US in pounds (174 lb), gym tracker in kg (78.9 kg). Convert between them without confusion.

Shipping and freight​

Carrier charges by kg, but your scale reads pounds. Convert to enter the correct weight on the shipping form.

Engineering and material specs​

Steel beam datasheet uses kg/m; your project is in lb/ft. Convert linear density without dropping a digit.

How it works​

  1. Enter the weight β€” Decimals OK. Composite imperial like "5 st 4 lb" parses correctly.
  2. Pick the source unit β€” g, kg, mg, ΞΌg, oz, lb, st (stone), short ton, long ton, metric tonne.
  3. See all conversions at once β€” Single screen shows the source weight in all common units. No flipping back and forth.
  4. Copy any converted value β€” Click any unit row to copy. Easy to paste into a shipping form or spreadsheet.

Examples​

Input: 70 kg

Output: 154.32 lb | 11 st 0.32 lb | 2469.18 oz | 70,000 g

Input: 1 lb

Output: 0.4536 kg | 16 oz | 0.07143 st (1/14 of a stone)

Input: 1 metric ton

Output: 1000 kg | 2204.62 lb | 0.984 long tons | 1.102 short tons

Frequently asked questions​

Are mass and weight the same thing?

In physics: no. Mass is the amount of matter; weight is the force gravity exerts on that mass. In everyday English, "weight" usually means mass β€” and that's how the converter treats it. For physics class, use Newtons (N) for true weight.

What's the difference between US and UK tons?

US "short ton" = 2000 lb β‰ˆ 907 kg. UK "long ton" = 2240 lb β‰ˆ 1016 kg. Metric "tonne" = 1000 kg β‰ˆ 2205 lb. Never assume a "ton" without context β€” always check.

How do I convert a person's weight from stones to pounds?

1 stone = 14 pounds. So "12 st 6 lb" = 12 Γ— 14 + 6 = 174 lb. The converter handles composite "X st Y lb" inputs automatically.

For cooking, should I weigh by grams or ounces?

Either works. Grams are more precise for small quantities (0.5 g resolution is common). Ounces work fine but the typical 1/8 oz resolution is coarser. Consistency within one recipe is more important than the unit choice.

Are the metric system and the SI system the same?

SI is the modern, formally defined version of the metric system. Practically synonymous for length, mass, time. Older "metric" units (calories, dyne, gauss) aren't in SI but are still used in some fields.

Tips​

  • Quick mental: 1 kg β‰ˆ 2.2 lb, 1 lb β‰ˆ 0.45 kg, 1 oz β‰ˆ 28 g.
  • For body weight in stones: divide pounds by 14 (or multiply kg by 0.157).
  • When shipping internationally, always specify the unit (kg or lb) β€” carriers default to different ones in different countries.
  • For precision (medicine, chemistry), always use SI/metric β€” imperial fractions invite errors.

Try it now​

The full weight-converter runs in your browser at https://ztools.zaions.com/weight-converter β€” no signup, no upload, no data leaves your device.

Open the tool β†—

Last updated: 2026-05-05 Β· Author: Ahsan Mahmood Β· Edit this page on GitHub