Unit Converter

Universal Unit Converter

Converting between different units of measurement is essential for travel, cooking, science, construction, and international communication. This calculator makes conversions instant and accurate.

Common Conversion Categories

Length/Distance:

• Metric: millimeters, centimeters, meters, kilometers
• Imperial: inches, feet, yards, miles
• Nautical: nautical miles, fathoms

Weight/Mass:

• Metric: milligrams, grams, kilograms, metric tons
• Imperial: ounces, pounds, tons
• Other: carats, stones

Volume:

• Metric: milliliters, liters
• US: fluid ounces, cups, pints, quarts, gallons
• UK: imperial units (slightly different!)

Temperature:

• Celsius (°C)
• Fahrenheit (°F)
• Kelvin (K)

Area:

• Square feet, square meters
• Acres, hectares
• Square miles, square kilometers

Speed:

• Miles per hour (mph)
• Kilometers per hour (km/h)
• Meters per second (m/s)
• Knots

Most Useful Conversions

Length:

• 1 inch = 2.54 cm
• 1 foot = 30.48 cm
• 1 meter = 3.28 feet
• 1 mile = 1.609 km
• 1 km = 0.621 miles

Weight:

• 1 ounce = 28.35 grams
• 1 pound = 0.454 kg
• 1 kg = 2.205 pounds
• 1 ton = 2,000 pounds

Volume (Liquid):

• 1 cup = 237 ml
• 1 pint = 473 ml
• 1 quart = 946 ml
• 1 gallon = 3.785 liters
• 1 liter = 0.264 gallons

Temperature:

• °F = (°C × 9/5) + 32
• °C = (°F - 32) × 5/9
• Water freezes: 0°C = 32°F
• Water boils: 100°C = 212°F
• Body temp: 37°C = 98.6°F

Real-World Applications

Traveling Abroad:

• Speed limits: 100 km/h = 62 mph
• Height restrictions: 2.5m = 8.2 feet
• Fuel efficiency: L/100km ↔ MPG
• Temperature: 25°C = 77°F (nice day!)

Cooking:

• Recipe from UK: 200g flour = 7 oz
• Oven temp: 180°C = 350°F
• Liquid measure: 250ml = 1 cup (approximately)

Shopping Online:

• Clothing: Size 42 EU = Size 10 US
• Monitor: 27" screen = 68.6 cm
• Package weight: 2 kg = 4.4 lbs

Home Improvement:

• Lumber: 2×4 inch = 5×10 cm (nominal)
• Paint coverage: sq ft ↔ sq meters
• Room size: 3m × 4m = 9.8ft × 13.1ft

Imperial vs. Metric

Metric System (most of the world):

• Based on powers of 10
• Easy conversions (×10, ×100, ×1000)
• Scientific standard
• Examples: meters, liters, grams

Imperial System (US, UK similarities with differences):

• Based on historical measurements
• Harder conversions (12 inches/foot, 3 feet/yard)
• Traditional in US
• Examples: feet, gallons, pounds

UK vs. US Differences:

• US gallon: 3.785 liters
• UK gallon: 4.546 liters
• Both use same pound (lb)

Quick Mental Approximations

For Travel:

• Kilometers to miles: Divide by 1.6 (or ÷ 8, × 5)
• Miles to kilometers: Multiply by 1.6
• Example: 100 km ≈ 60 miles

For Temperature:

• Quick °C to °F: Double it, add 30
• Example: 20°C → 40 + 30 = 70°F (actual: 68°F)
• Quick °F to °C: Subtract 30, divide by 2
• Example: 70°F → 40 / 2 = 20°C (actual: 21°C)

For Cooking:

• 1 cup ≈ 250 ml (actual: 237)
• 1 oz ≈ 30 g (actual: 28.35)
• 1 lb ≈ 500 g (actual: 454)

Common Mistakes to Avoid

Temperature Confusion:

• Don't just multiply °C by 1.8 (must also add 32!)
• Room temperature: 20-22°C = 68-72°F (not 36-40°F!)

UK vs. US Volumes:

• Verify which system when using international recipes
• US tablespoon: 14.8 ml
• UK tablespoon: 17.7 ml

Weight vs. Volume:

• 1 cup of water ≠ 1 cup of flour (by weight)
• Volume measures space, weight measures mass
• 1 cup water = 237 ml = 237 g
• 1 cup flour = 237 ml = 120-140 g

Scientific Notation

Large/Small Numbers:

• 1 kilometer = 10³ meters = 1,000 m
• 1 millimeter = 10⁻³ meters = 0.001 m
• Useful for scientific calculations

Precision Matters

When Exact Conversions Matter:

• Scientific experiments
• Legal documents
• Construction specifications
• Medical dosing

When Approximations Are Fine:

• Casual cooking
• Estimating travel time
• General shopping
• Casual conversations

Fun Facts

Historical Origins:

• Inch: Originally width of a thumb
• Foot: Literally the length of a foot
• Mile: From Latin "mille passus" (1,000 paces)
• Meter: 1/10,000,000 of distance from equator to North Pole

Why 12 inches in a foot?

• 12 is divisible by 2, 3, 4, and 6
• Made fractions easier before decimals were common

Why the US uses Imperial:

• Started using it before metric was invented
• Expensive and difficult to change all infrastructure
• Many US industries still use metric (science, military, medicine)

Specialized Conversions

Cooking Temperature:

• "Low": 150°C = 300°F
• "Medium": 180°C = 350°F
• "Hot": 200°C = 400°F
• "Very hot": 230°C = 450°F

Running Pace:

• 5 min/km = 8 min/mile
• 6 min/km = 9.66 min/mile
• 7 min/km = 11.27 min/mile

Fuel Economy:

• 25 MPG = 9.4 L/100km
• 30 MPG = 7.8 L/100km
• Lower L/100km = better (opposite of MPG!)

Use this calculator to convert between any units quickly and accurately, whether you're cooking, traveling, or working on a project!