Weight & Mass Converter
Enter a value → choose units → convert instantly. Click any row in the bulk table to set it as your target unit.
Bulk Conversion Table — All 32 Units at Once
Click any row to set it as the target unit. Table updates live as you type.
| Unit | Result | Symbol / Abbrev. |
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The 5 Weight Unit Systems — Complete Guide
Metric, imperial, troy, apothecary and scientific weight systems explained with history and usage
Weight measurement is divided into five major systems, each developed for different historical, commercial and scientific purposes. This converter handles all five — from everyday metric and imperial units to specialist systems like troy weights for precious metals, apothecary weights for pharmacy, and SI units for scientific precision.
Most Common Weight Conversions — Quick Reference
The most-searched weight conversions with exact values and easy-to-remember approximations
70 kg = 154.32 lb
100 kg = 220.46 lb
150 lb = 68.04 kg
200 lb = 90.72 kg
10 st = 63.503 kg
12 st = 76.204 kg
70 kg = 11 st 0.3 lb
80 kg = 12 st 8.1 lb
100 g = 3.5274 oz
500 g = 17.637 oz
8 oz = 226.796 g
16 oz = 453.592 g
10 ozt = 311.035 g
1 troy lb = 373.242 g
1 t = 1,000 kg
1 short ton = 907.185 kg
Real-World Weight Reference — From Atoms to Blue Whales
Putting weight units in context with everyday objects, animals, food and scientific extremes
One of the best ways to understand weight conversions is to anchor them to real-world references — from the mass of an electron to the weight of a blue whale and beyond. The table below spans 60 orders of magnitude, giving you an intuitive feel for what the numbers mean.
| Object / Item | Metric | Imperial | Notes |
|---|---|---|---|
| ⚛️ Electron mass | 9.109 × 10⁻³¹ kg | ≈ 2.0 × 10⁻³⁰ lb | Lightest stable particle with mass |
| 🧬 Single DNA base pair | ~650 Da (daltons) | ≈ 1.08 × 10⁻²⁴ oz | Dalton ≈ 1 proton mass = 1.66 × 10⁻²⁷ kg |
| 💊 Aspirin tablet (standard) | 325 mg | 5.01 grains | 0.325 g; typical OTC dose |
| 🪙 US quarter coin | 5.670 g | 0.2 oz | Exact US Mint specification |
| 🥚 Large chicken egg | ~60 g | ~2.12 oz | Grade A large (USA standard) |
| 🍎 Medium apple | ~182 g | ~6.4 oz / 0.4 lb | Varies significantly by variety |
| 🍫 Standard chocolate bar | 100 g | 3.53 oz | Common European standard size |
| 📱 iPhone 15 Pro | 187 g | 6.60 oz | Apple official specification |
| 🏋️ Standard barbell plate (large) | 20 kg | 44.09 lb | Olympic standard bumper plate |
| 🧑 Average adult human | ~70 kg | ~154 lb / 11 st | Global average; varies by region |
| 🐻 Polar bear (male) | 350–700 kg | 772–1,543 lb | Largest land carnivore |
| 🚗 Average car (petrol) | ~1,400 kg | ~3,086 lb / 1.37 tons | European average; EVs ~200 kg heavier |
| 🐘 African elephant (bull) | ~6,000 kg | ~13,228 lb / 5.9 tons | Heaviest land animal |
| 🐋 Blue whale (adult) | ~150,000 kg | ~330,693 lb / 165 tons | Heaviest animal ever known |
| 🗼 Eiffel Tower | 7,300 tonnes | 8,047 short tons | Iron structure only; not foundation |
| 🌍 Earth | 5.972 × 10²⁴ kg | 1.317 × 10²⁵ lb | Determined by gravitational astronomy |
| ☀️ Sun | 1.989 × 10³⁰ kg | ≈ 4.385 × 10³⁰ lb | ~333,000 × Earth mass |
The History of Weight Measurement — From Grain Seeds to the Kilogram Prototype
How humanity progressed from inconsistent natural objects to the internationally agreed kilogram
The earliest weight standards were derived from nature. The grain — literally a single dry grain of wheat or barleycorn — was one of the first standardised weight units, used by the ancient Egyptians, Romans and later in medieval Europe. The grain is still used today in the apothecary system (for medicines) and for bullet and gunpowder weights in ballistics. 1 grain = exactly 64.79891 milligrams.
The ancient Egyptians used the qedet (~9.33 g) and the deben (~91 g) as primary commercial weights, standardised in bronze and stone. Egyptian balance scales dating to 3000 BCE are remarkably accurate — surviving examples show measurement precision of better than 1% — used for weighing gold dust and grain in trade. The Indus Valley civilisation simultaneously developed their own cubic stone weights with a precise doubling sequence (1, 2, 4, 8, 16, 32, 64 ratios).
The avoirdupois system — the standard for everyday goods in English-speaking countries — emerged in 14th-century England for trading bulk goods. Its name comes from the Old French avoir de pois meaning "goods of weight." By the 15th century it had stabilised at 16 ounces to the pound, the system still in use in the US today.
The troy system is older still, originating in the medieval trading city of Troyes, France, where the great Champagne fairs attracted merchants from across Europe. The troy pound of 12 troy ounces (~373 g) became the standard for gold, silver and gemstones across Europe. It is still used today exclusively for precious metals — every gold price you see quoted is in troy ounces.
The French Revolution again catalysed modern standardisation. In 1799, the kilogramme was defined as the mass of 1 litre of water at 4°C — materialised as the Kilogramme des Archives, a platinum cylinder. In 1889 this was replaced by the International Prototype Kilogram (IPK), a platinum-iridium cylinder kept at Sèvres, France — and remained the world's mass standard for 130 years.
In 2019, the kilogram was finally redefined in terms of fundamental physical constants — specifically Planck's constant (h = 6.62607015 × 10⁻³⁴ J·s). This makes it reproducible to any precision anywhere in the universe, free from the risk of the physical prototype changing mass (which the IPK did, by roughly 50 micrograms over its lifetime).
Fascinating Weight Facts, Records & Science
Extraordinary masses, surprising weight comparisons and records from physics to nature
The International Prototype Kilogram Gained & Lost Weight
The platinum-iridium IPK cylinder kept in Sèvres was the world's only true kilogram from 1889–2019. Over those 130 years, comparisons with its official copies revealed the IPK had changed mass by up to 50 micrograms — 50 millionths of a gram. This fundamental problem (a physical artefact can change) was why physicists worked to redefine the kilogram in terms of Planck's constant in 2019.
You Weigh Less at the Equator Than at the Poles
Due to Earth's oblate shape (bulge at equator) and rotation, gravity varies with latitude. At the equator (further from Earth's centre + centrifugal effect of rotation), you weigh about 0.5% less than at the poles. A person weighing 80 kg at the North Pole would weigh ~79.6 kg at the equator — a difference of ~400 grams. This is why precision weighing facilities must apply latitude corrections.
The Carat — Gemstone Weight Standardised on a Seed
The metric carat (200 mg = 0.2 g) used for gemstones was originally based on the carob seed (Ceratonia siliqua), which Mediterranean traders believed had a remarkably consistent weight (~200 mg). The metric carat was internationally standardised in 1907. Note: diamond "carat" (mass) is different from gold "karat" (purity — 24 karat = pure gold). A 1-carat diamond = 0.2 g = 0.00705 oz.
Olympic Weightlifting — The Numbers Are Staggering
The current Olympic weightlifting world record in the total (snatch + clean & jerk) stands at 477 kg (1,051.4 lb), set by Lasha Talakhadze (Georgia) in the +109 kg category at the 2021 Tokyo Olympics. His clean & jerk record alone is 267 kg (588.6 lb) — more than three times his own body weight lifted from the floor to overhead in one movement.
Your Weight on Other Planets
Weight depends on gravity. A person weighing 70 kg on Earth (686 N) would "weigh" (experience gravitational force equivalent to): Mars: 26.5 kg · Moon: 11.6 kg · Jupiter: 165.5 kg · Saturn: 74.5 kg · Venus: 63.4 kg · Neutron star surface: ~10¹⁴ kg (approximately 100 trillion kg of apparent weight). Their mass remains 70 kg throughout.
The Human Brain — Surprisingly Light
The adult human brain weighs approximately 1.3–1.4 kg (2.87–3.09 lb) — only about 2% of total body weight, yet consuming ~20% of the body's energy. Einstein's brain weighed 1,230 g — slightly below average. The brain of a sperm whale (~8 kg / 17.6 lb) is the largest of any animal, yet whale intelligence is thought to correlate more with brain-to-body ratio than absolute mass.
The Higgs Boson — Mass From the Field
The Higgs boson, discovered at CERN in 2012, has a mass of approximately 125.25 GeV/c² ≈ 2.23 × 10⁻²⁵ kg. The Higgs field that permeates the universe is what gives fundamental particles (electrons, quarks) their mass. Without the Higgs field, all particles would be massless and travel at the speed of light — matter as we know it could not exist.
The Heaviest Living Thing on Earth
The heaviest single living organism is not an animal but a plant: Pando, a clonal colony of quaking aspen in Utah, USA. Its ~47,000 genetically identical stems share a single root system estimated to weigh approximately 6 million kg (6,000 tonnes / 13.2 million lb). The blue whale (~150 tonnes) is the heaviest individual animal — but Pando outweighs it 40 times over.
How to Use the Weight Converter
Step-by-step guide to getting instant, accurate conversions across all 32 weight units
- 1
Enter Your Value
Type any positive number — including decimals (e.g., 75.5) and very small values (e.g., 0.001) — into the input field. The converter accepts standard decimal notation. As you type, the bulk conversion table updates live across all 32 units simultaneously so you can see multiple results without pressing any button.
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Select From & To Units
Choose your source unit from the "From Unit" dropdown and your target unit from the "To Unit" dropdown. Units are grouped into five categories (Metric, Imperial/Avoirdupois, Troy, Apothecary, Scientific) for easy navigation. Use the swap button (⇆) to instantly reverse the conversion direction — useful when you want to check the inverse calculation.
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Click Convert or Use Live Results
Press the Convert button to see the full result panel with the large-format answer, conversion factor, inverse factor and a system category label. Or simply read the live-updating bulk table — it shows your value in all 32 units at once. Click any row in the table to instantly set that unit as your target and see the highlighted result.
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Review Step-by-Step Working
Expand the Step-by-Step Calculation panel to see the exact conversion path. All conversions use kilograms as the base unit: value × fromToKg ÷ toToKg. The panel shows the conversion factor for both directions, the intermediate value in kilograms, and the final result — ideal for students, engineers and anyone who needs to verify or cite the conversion method.
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Share Your Result
Use Copy, WhatsApp or Twitter to share your conversion. The share text includes the original value, converted value, both units, conversion factor and the tool URL. Your last 20 conversions are saved in the sidebar history for quick recall — useful when switching between multiple conversions during a recipe, workout or engineering calculation.
Frequently Asked Questions
Common weight conversion questions answered with exact values and practical examples