Length & Area

• 1 foot0.305 m
• 1 inch2.54 cm
• 1 mile5,280 ft1.61 km
• 1 acre43,560 ft²4,046.9 m²
• 1 hectare10,000 m²
• 1 square meter1.19 yd²

Volume & Weight

• 1 gallon (US)3.785 L8.34 lb of water
• 1 cubic foot of water7.48 gal62.4 lb
• 1 cubic meter of water1,000 kg1,000 L264 gal
• 1 acre foot of water326,000 gal
• 1 pound0.454 kg
• 1 ton2,000 lb
• 1 metric ton2,205 lb1,000 kg

Flow

• 1 cubic foot per second0.646 MGD448.8 gpm
• 1 million US gallons per day694 gpm1.55 ft³/sec
• 1 liter per second0.0864 MLD

Pressure & Head

• 1 atm33.9 ft of water10.3 m of water14.7 psi101.3 kPa
• 1 foot of water0.433 psi
• 1 meter of water9.8 kPa
• 1 pound per square inch2.31 ft of water6.89 kPa

Power

• 1 horsepower0.746 kW746 W33,000 ft lb/min

Reference Values

• 1 grain per US gallon17.1 mg/L
• 1%10,000 mg/L
• π or pi3.14
• Population Equivalent, hydraulic100 gal/person/day378.5 L/person/day
• Population Equivalent, organic0.17 lb BOD/person/day0.077 kg BOD/person/day