Common Unit Conversions

Water treatment operators should be familiar with these common unit conversions.

Length:

12 in = 1 ft
3 ft = 1 yd
5,280 ft = 1 mi

Area:

144 sq in = 1 sq ft
43,560 sq ft = 1 acre

Weight:

1,000 mg = 1 gm
1,000 gm = 1 kg
454 gm = 1 lb
2.2 lbs = 1 kg
1 lb of water = 27.7 cu in
1 gal of water = 8.333 pounds
1 cu ft of water = 62.5 pounds

Volume:

7.48 gal = 1 cu ft
1,000 mL = 1 liter
3.785 L = 1 gal
231 cu in = 1 gal

Power:

0.746 kW (746 W) = 1 HP
1 kW = 1,000 Watts 

8.34 lbs = 1 gal
64.4 lbs = 1 cu ft

Dosage:

17.1 mg/L = 1 grain/gal
64.7 mg = 1 grain
8.34 lb/million gal = 1 mg/L

2.31 ft water = 1 psi
0.433 psi = 1 ft water
1.133 ft water = 1 in Mercury

Flow:

694 GPM = 1 MGD
1.55 CFS = 1 MGD