How many gallons is 30 lbs of water?

"Pounds to Gallons" Calculator
How many gallons in
lb

How many gallons is 30 lbs of water?

Answer

30 lbs of water is
3.6 US gallons

Water is taken at 20 °C (68 °F), where its density is 0.998 kg/L, so one US gallon of it weighs 8.33 lbs. Colder water is a touch denser, so the same weight of it takes slightly less room.

In imperial (UK) gallons of 4.54609 L instead of 3.785411784 L, 30 lbs of water would be 3 UK gallons.

How the volume of 30 lbs of water was worked out

gallons = pounds × 0.45359237 ÷ (density in kg/L × 3.785411784)

A US gallon is exactly 3.785411784 liters and a pound is exactly 0.45359237 kilograms: the weight becomes kilograms, and the density turns kilograms into liters — and the liters become gallons.

30 lb × 0.45359237 ÷ (0.998 kg/L × 3.785411784)

≈

3.6 US gallons

(three point six gallons)

The density comes from FAO/INFOODS Density Database v2.0: liquid water at 20 °C; rounding to 1.00 kg/L is fine for everyday use.

The other way round: what one US gallon of this weighs

This page starts from a weight and answers in gallons. The opposite question — how much a given number of gallons weighs — is what the gallons to pounds calculator is for, and in metric units the same question is liters to kilograms. All of them read one density table, so their numbers agree.

For water the density is 0.998 kg/L, so 30 lbs is 3.6 gallons — and one US gallon of it weighs 8.33 lbs.

If the substance is not known in advance, start from how many gallons 30 lbs is — the same weight across every substance at once.

See Also

  • Gallons to Pounds - How much a gallon of water, milk, gasoline, diesel, oil or propane weighs in pounds — by density
  • Pounds to Liters - How many liters a pound of water, milk, oil or propane takes — by density
  • Kilograms to Liters - How many liters are in a kilogram of water, honey, gasoline, sand and other substances — by density
  • Liters to Gallons - Convert Liters to US Gallons
  • Lbs to Kg - Convert Pounds to Kilograms

About "Pounds to Gallons" Calculator

This calculator converts pounds to US gallons through the density of the substance: volume equals weight divided by the weight of one gallon. The lighter the substance, the more gallons the same pounds fill — a pound of propane takes almost twice the room of a pound of water. When no substance is named, the answer is for water, and the table shows every other liquid next to it. For example, it can help you find out how many gallons is 30 lbs of water? (The answer is: 3.6). The answer is in US liquid gallons; every result page also names the same volume in imperial gallons, which are about a fifth larger.
"Pounds to Gallons" Calculator
How many gallons in
lb

How many gallons 30 lbs of each substance takes

SubstanceVolume of 30 lbsOne US gallon weighsDensity, kg/L
Milk3.49 gallons8.6 lbs1.03
Propane7.08 gallons4.24 lbs0.5076
Vegetable oil3.91 gallons7.68 lbs0.92
Water3.6 gallons8.33 lbs0.998

FAQ

How many gallons is 30 lbs of water?

30 lbs of water is 3.6 US gallons

How do you work out the volume of 30 lbs of water?

Divide the weight by the weight of one US gallon. One US gallon of water weighs 8.33 lbs (density 0.998 kg/L), so 30 lbs is 3.6 US gallons — division rarely comes out even, so the figure is rounded.

How many gallons is a pound of water?

0.12 US gallons at 20 °C (68 °F), because a US gallon of water weighs 8.33 lbs there. Cold water is a touch denser — at 4 °C (39 °F), its densest, a gallon weighs 8.35 lbs — so the same weight of it takes a fraction of a percent less room.

How many imperial gallons is 30 lbs of water?

3 UK gallons, against 3.6 US gallons. The imperial gallon is 4.54609 liters, the US one 3.785411784, so the same weight fills about a fifth fewer imperial gallons.