Enhanced Unit Conversions Calculator - Length, Weight, Temperature, Currency & More

Length Conversions

From:

To:

Enter a length value to convert

1m → ft

1ft → m

1km → mi

1mi → km

1in → cm

1cm → in

Weight/Mass Conversions

From:

To:

Enter a weight value to convert

1kg → lb

1lb → kg

1g → oz

1oz → g

Temperature Conversions

Temperature Value:

From Unit:

Celsius (°C)

Fahrenheit (°F)

273.15

Kelvin (K)

491.67

Rankine (°R)

Enter a temperature to see all conversions

0°C

32°F

100°C

212°F

Volume Conversions

From:

To:

Enter a volume value to convert

1L → gal

1gal → L

1cup → mL

1mL → cup

Area Conversions

From:

To:

Enter an area value to convert

Time Conversions

From:

To:

Enter a time value to convert

Unit Conversion Reference & Learning

Unit Systems

International System of Units (SI)

Length

Base unit: meter (m)
Common: km, cm, mm

Mass

Base unit: kilogram (kg)
Common: g, mg, metric ton

Time

Base unit: second (s)
Common: min, h, day, year

Temperature

Base unit: Kelvin (K)
Common: Celsius (°C)

Imperial/US Customary System

Length

inch, foot, yard, mile
12 in = 1 ft, 3 ft = 1 yd

Weight

ounce, pound, stone, ton
16 oz = 1 lb, 14 lb = 1 stone

Volume

fluid ounce, cup, pint, quart, gallon
8 fl oz = 1 cup, 4 cups = 1 qt

Temperature

Fahrenheit (°F)
Water freezes at 32°F, boils at 212°F

Conversion Relationships

1 meter = 3.28084 feet = 39.3701 inches
1 kilogram = 2.20462 pounds
1 liter = 0.264172 US gallons = 1.05669 US quarts

Conversion Formulas

Temperature Conversions

Celsius ↔ Fahrenheit

°F = (°C × 9/5) + 32
°C = (°F - 32) × 5/9

Celsius ↔ Kelvin

K = °C + 273.15
°C = K - 273.15

Fahrenheit ↔ Rankine

°R = °F + 459.67
°F = °R - 459.67

Kelvin ↔ Rankine

°R = K × 9/5
K = °R × 5/9

Length Conversion Factors

1 km = 1000 m = 0.621371 mi
1 m = 100 cm = 1000 mm = 3.28084 ft
1 ft = 12 in = 0.3048 m
1 in = 2.54 cm (exact)
1 mi = 5280 ft = 1.60934 km
1 nautical mile = 1.852 km

Weight/Mass Conversion Factors

1 kg = 1000 g = 2.20462 lb
1 lb = 16 oz = 453.592 g
1 stone = 14 lb = 6.35029 kg
1 metric ton = 1000 kg = 2204.62 lb

Volume Conversion Factors

1 L = 1000 mL = 0.264172 US gal
1 US gal = 4 qt = 8 pt = 16 cups = 128 fl oz
1 cup = 8 fl oz = 16 tbsp = 48 tsp
1 m³ = 1000 L = 35.3147 ft³
1 ft³ = 1728 in³ = 28.3168 L

Important Physical Constants

Universal Constants

Speed of Light

c = 299,792,458 m/s
≈ 186,282 mi/s

Gravitational Constant

G = 6.674 × 10⁻¹¹ m³/kg⋅s²
Universal gravitation

Planck's Constant

h = 6.626 × 10⁻³⁴ J⋅s
Quantum mechanics

Avogadro's Number

Nₐ = 6.022 × 10²³ mol⁻¹
Particles per mole

Earth and Atmospheric Constants

Standard Gravity

g = 9.80665 m/s²
≈ 32.174 ft/s²

Atmospheric Pressure

1 atm = 101,325 Pa
= 760 mmHg = 14.696 psi

Earth's Radius

Mean: 6,371 km
≈ 3,959 miles

Water Properties

Density: 1000 kg/m³
Freezes: 0°C, Boils: 100°C

Energy and Power Units

1 J = 1 N⋅m = 1 W⋅s
1 kWh = 3.6 × 10⁶ J
1 cal = 4.184 J (thermochemical calorie)
1 BTU ≈ 1055 J
1 eV = 1.602 × 10⁻¹⁹ J

Worked Examples

Example 1: Temperature Conversion

Problem: Convert 25°C to Fahrenheit

Solution:
• Use formula: °F = (°C × 9/5) + 32
• °F = (25 × 9/5) + 32
• °F = (25 × 1.8) + 32
• °F = 45 + 32 = 77

Answer: 25°C = 77°F

Example 2: Length Conversion

Problem: Convert 5 kilometers to miles

Solution:
• 1 km = 0.621371 miles
• 5 km × 0.621371 miles/km
• = 3.106855 miles

Answer: 5 km ≈ 3.11 miles

Example 3: Volume Conversion

Problem: Convert 2.5 liters to US gallons

Solution:
• 1 L = 0.264172 US gallons
• 2.5 L × 0.264172 gal/L
• = 0.66043 gallons

Answer: 2.5 L ≈ 0.66 gallons

Example 4: Weight Conversion

Problem: Convert 150 pounds to kilograms

Solution:
• 1 lb = 0.453592 kg
• 150 lb × 0.453592 kg/lb
• = 68.0388 kg

Answer: 150 lb ≈ 68.04 kg