Free Tool · 6 Categories · Instant Conversion

Unit Converter

Convert between length, mass, area, volume, speed and time units — with instant results as you type.

1 Choose a category
2 Enter the value to convert
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What this unit converter does

This tool converts between units across six physical quantities: length, mass, area, volume, speed and time. Choose a category, pick the "from" and "to" units, and enter the value — the result appears instantly. All conversions use exact or standard factors, and the page includes a quick-reference table of common equivalents for the selected category so you can sanity-check any result. The converter uses the same unit tables shared by the individual length, mass, area, volume, speed and time converters, so a value converted here matches the result you'd get from the dedicated page for that category.

How the conversion works

General unit conversion
result = value × factorfrom→SI factorto→SI

Every unit in the converter is defined by a factor that converts it to the SI base unit of its category — metres for length, kilograms for mass, square metres for area, cubic metres for volume, metres per second for speed, and seconds for time. To convert from unit A to unit B, multiply the value by A's factor and divide by B's factor. This two-step path through SI guarantees consistency: it does not matter how many intermediate units you go through, the result is the same.

Example: 10 metres to feet

  • metre → SI: 1 m = 1 m, factor = 1
  • foot → SI: 1 ft = 0.3048 m, factor = 0.3048
  • result = 10 × 1 / 0.3048 = 32.8084 ft

Example: 72 km/h to m/s

  • km/h → SI: 1 km/h = 1000/3600 m/s ≈ 0.277778 m/s
  • m/s → SI: 1 m/s = 1 m/s, factor = 1
  • result = 72 × 0.277778 / 1 = 20 m/s

Worked examples

Length — 5 km to miles

  1. 1 km = 1000 m; 1 mile = 1609.344 m.
  2. Result = 5 × 1000 / 1609.344 = 3.10686 miles.
  3. This is the "5K run" distance — about 3.1 miles.

Length — 6 feet (height) to metres

  1. 1 ft = 0.3048 m.
  2. Result = 6 × 0.3048 = 1.8288 m.
  3. A person 6 feet tall is about 1.83 metres.

Mass — 75 kg to pounds

  1. 1 kg = 2.20462 lb.
  2. Result = 75 × 2.20462 = 165.35 lb.
  3. 75 kg is a common adult weight — around 165 pounds.

Mass — 500 g to ounces

  1. 1 g = 0.035274 oz.
  2. Result = 500 × 0.035274 = 17.637 oz.
  3. Just over a pound — a typical serving-sized package.

Volume — 2 litres to cubic centimetres

  1. 1 L = 1000 cm³.
  2. Result = 2 × 1000 = 2000 cm³.
  3. The standard soda bottle volume in metric units.

Speed — 100 km/h to m/s

  1. 1 km/h = 5/18 m/s ≈ 0.277778.
  2. Result = 100 × 0.277778 = 27.78 m/s.
  3. About the speed of a car on a Pakistani motorway (M-2).

Time — 3 hours to minutes and seconds

  1. 1 h = 60 min = 3600 s.
  2. Result = 3 × 60 = 180 minutes = 3 × 3600 = 10800 seconds.
  3. Three hours is 180 minutes or 10,800 seconds.

Area — 1 acre to square metres

  1. 1 acre = 4046.86 m².
  2. Result = 1 × 4046.86 = 4046.86 m².
  3. About 0.4 hectares — a Pakistani "kanal" is roughly 505.86 m², so 1 acre ≈ 8 kanals.

Common conversion factors at a glance

These are the most frequently used factors. Memorising a few makes quick mental estimates possible, and having them on hand is useful for exam checks.

Conversion Factor Reverse
km → miles× 0.621371miles × 1.609344 = km
m → feet× 3.28084feet × 0.3048 = m
cm → inches× 0.393701inches × 2.54 = cm
kg → pounds× 2.20462pounds × 0.453592 = kg
g → ounces× 0.035274ounces × 28.3495 = g
L → gallons (US)× 0.264172gallons × 3.78541 = L
m³ → cubic feet× 35.3147ft³ × 0.0283168 = m³
km/h → m/s× 0.277778m/s × 3.6 = km/h
mph → km/h× 1.60934km/h × 0.621371 = mph
knots → km/h× 1.852km/h × 0.539957 = knots
hours → minutes× 60minutes × 1/60 = hours
days → hours× 24hours × 1/24 = days

Note that "gallon" here means the US gallon (3.785 L). The UK imperial gallon is larger at 4.546 L. For most Pakistani contexts, litres and millilitres are the standard for volume, and gallons appear mainly in imported or US-context problems.

Common mistakes to avoid

  • Confusing mass and weight. The mass converter converts between mass units (kg, g, lb, oz). Weight is a force in newtons — W = mg. If a problem gives weight and asks for mass, divide by 9.8 first.
  • Using a linear conversion factor for area or volume. Since 1 m = 100 cm, one might assume 1 m² = 100 cm², but it is actually 10,000 cm² — the factor is squared. Similarly, 1 m³ = 1,000,000 cm³. The converter handles this correctly, but students often get it wrong by hand.
  • Mixing up litres and cubic metres. 1 m³ = 1000 L. A 1-litre bottle is 0.001 m³, not 1 m³. And 1 L = 1000 mL = 1000 cm³, so liquids measured in mL and solids measured in cm³ share the same scale.
  • Using statute miles when nautical miles are meant. A statute mile is 1609.344 m; a nautical mile is exactly 1852 m. Aviation and marine problems use nautical miles, and the difference is 15%.
  • Assuming US and UK gallons are the same. US gallon = 3.785 L, UK (imperial) gallon = 4.546 L. Nearly 20% difference — enough to matter in fuel or chemistry problems.
  • Forgetting that time conversion is base-60, not base-10. 1.5 hours is 90 minutes, not 1 hour 50 minutes. 2 hours 30 minutes is 2.5 h, not 2.3 h. Decimal time notation (used by the calculator) is different from clock time.
  • Applying a conversion twice. If you convert metres to feet and then multiply by 0.3048 again, you are effectively converting to inches. Track the direction carefully, or use the swap button.

FAQ

What units does this converter support?

Six categories: length (metres, kilometres, centimetres, millimetres, miles, feet, inches, yards), mass (kilograms, grams, milligrams, pounds, ounces, tonnes), area (square metres, square kilometres, square feet, square yards, acres, hectares), volume (litres, millilitres, cubic metres, cubic centimetres, gallons, cubic feet), speed (m/s, km/h, mph, knots, ft/s), and time (seconds, minutes, hours, days, weeks).

How do I convert metres to feet?

Multiply by 3.28084. For example, 10 m = 10 × 3.28084 = 32.8084 feet. The converter uses this factor exactly, so entering 10 m gives the precise result. Conversely, 1 foot = 0.3048 m exactly.

How do I convert km/h to m/s?

Multiply km/h by 5/18 (or divide by 3.6). For example, 72 km/h = 72 × 5/18 = 20 m/s. The inverse conversion, m/s to km/h, is multiply by 3.6. This factor comes from 1000 m per km divided by 3600 seconds per hour.

How do I convert kilograms to pounds?

Multiply kilograms by 2.20462. For example, 75 kg = 75 × 2.20462 = 165.35 lb. One pound is defined exactly as 0.45359237 kg, so this factor is exact rather than approximate.

What is the difference between mass and weight?

Mass is the amount of matter in a body, measured in kilograms. Weight is the gravitational force acting on that mass, measured in newtons (W = mg). The mass converter converts between mass units only — kilograms, grams, pounds, ounces. To convert to weight in newtons, multiply the mass by 9.8.

Does the converter work for compound units?

The converter handles one unit category at a time. Compound units like kg/m³ (density) or N·m (torque) involve multiple categories. Convert each component separately, or use a dedicated tool like the density calculator for density conversions.

Dedicated converters for each category

Each dedicated converter offers the same conversion but with more room for worked examples, unit-specific context, and category-tailored tips. This master page is ideal for quick lookups across categories; the dedicated pages are better for deep study of a single conversion type.

Related tools

Related Hira Academy resources

Practice unit conversions with our Class 9 notes and Class 10 notes, and track term progress with the free Student Portal.

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