Units Cheatsheet

Length

• 1 inch = 25.4 mm
• 1 foot = 30.48 cm = 12 inches
• 1 yard = 91.44 cm = 3 feet
• 1 mile = 1.609 km = 5,280 ft
• 1 nautical mile = 1.852 km = 1.151 miles
• 1 light-year = 9.461 × 10¹² km

Mass / weight

• 1 ounce = 28.35 g
• 1 pound = 453.59 g = 16 oz
• 1 stone = 6.35 kg = 14 lb
• 1 US ton = 907.18 kg = 2,000 lb
• 1 metric tonne = 1,000 kg
• 1 carat = 200 mg

Volume

• 1 fl oz = 29.57 ml
• 1 cup = 236.59 ml = 8 fl oz
• 1 pint = 473.18 ml = 2 cups
• 1 quart = 946.35 ml = 4 cups
• 1 US gallon = 3.785 L = 16 cups
• 1 imperial gallon = 4.546 L (UK)
• 1 barrel (oil) = 158.99 L = 42 US gal

Temperature

• °F = °C × 9/5 + 32
• °C = (°F − 32) × 5/9
• K = °C + 273.15
• Water freezes: 0°C / 32°F / 273.15 K
• Water boils (1 atm): 100°C / 212°F
• Body temp: 37°C / 98.6°F

Pressure

• 1 atm = 101.325 kPa
• 1 atm = 14.696 psi
• 1 atm = 760 mmHg
• 1 bar = 100 kPa = 14.504 psi
• Sea level avg: 14.7 psi

Energy

• 1 cal = 4.184 J
• 1 food calorie (Cal) = 1,000 cal = 4,184 J
• 1 BTU = 1,055.06 J
• 1 kWh = 3.6 × 10⁶ J = 3,412 BTU
• 1 ft·lb = 1.356 J

Time

• 1 minute = 60 sec
• 1 hour = 60 min = 3,600 sec
• 1 day = 86,400 sec
• 1 week = 604,800 sec
• 1 year ≈ 3.156 × 10⁷ sec
• 1 nanosecond = 10⁻⁹ sec

Speed

• 1 mph = 1.609 km/h
• 1 m/s = 3.6 km/h = 2.237 mph
• 1 knot = 1.852 km/h = 1.151 mph
• Sound (air, 20°C) = 343 m/s
• Light = 299,792,458 m/s