15 cubic feet to gallons

Fifteen cubic feet is 112.2078 US gallons

25,920 cubic inches, 231 to the gallon

Fifteen cubic feet is 112.2078 US gallons. Work it from cubic inches and nothing hides: 15 x 1,728 = 25,920 cubic inches, and 25,920 / 231 = 112.2078. The one step version multiplies by 7.48051948051948 and reaches the same decimal place.

Metric runs exact. Fifteen cubic feet is 424.7527 liters, and those liters divide by 4.54609 to give 93.4325 imperial gallons. NIST Special Publication 811, Appendix B lists the US gallon at 3.785412 liters next to the cubic foot, so the whole chain survives a check with a calculator. The BIPM SI Brochure, 9th edition, keeps the inch at 25.4 mm exactly, which is why the liters per cubic foot never drift.

In cubic yards the figure is 0.5556, since 15 / 27 = 0.5556, and in dry gallons it is 96.4277. The table covers ten to twenty cubic feet, the band where most tanks, totes and trailer loads sit.

Fifteen lands in a useful place. It is just over two 55 gallon drums, since 112.2078 / 55 = 2.0401, and three quarters of a 150 gallon tank. A 110 gallon sprayer holds 14.7049 cubic feet, so fifteen cubic feet fills one with 2.21 gallons to spare.

Ten cartons, five crates, or a corner of a storage unit

Carton sizes and what a 5 by 5 unit holds

Movers sell boxes by the cubic foot for a reason. A book carton measuring 18 by 12 by 12 inches is 2,592 cubic inches, or 1.5 cubic feet, so fifteen cubic feet is ten of them. A large carton at 18 by 18 by 16 inches is 5,184 cubic inches, or 3 cubic feet, and only five of those fill the same space.

Wardrobe cartons are the other extreme. At 24 by 24 by 18 inches one holds 10,368 cubic inches, or 6 cubic feet, so fifteen cubic feet takes two and a half of them, which in practice means two wardrobes and a carton of shoes. The box count changes with the shape of the load, while the volume does not.

Storage units are priced on the same arithmetic. A 5 by 5 foot unit with an 8 foot ceiling measures 200 cubic feet, so fifteen cubic feet is 7.5 percent of the floor to ceiling space and the unit swallows 13.33 loads of this size. An enclosed trailer 6 by 12 feet with 6 foot walls is 432 cubic feet, which is 28.8 of these loads.

Weight is the part volume cannot answer. A carton of books runs far heavier than a carton of bedding at the same 1.5 cubic feet, which is why movers weigh the truck instead of counting boxes, and why the heavy cartons belong at the bottom of the stack and over the axle.

Fifteen cubic feet reads differently on paper and in a hallway. Ten book cartons stacked two high fill about five feet of wall to hip height and no more, which looks small on the tailgate of a truck and large in a spare bedroom. That gap between the two impressions is the reason a volume figure beats a box count when a load is being planned.

Inside and outside a 15 cubic foot chest freezer

Liner volume against cabinet volume

The label on a chest freezer counts the liner, not the cabinet. A freezer whose liner measures 45 by 24 by 24 inches is 25,920 cubic inches inside, which is fifteen cubic feet exactly. The lid gasket, the step over the compressor and the hanging basket all sit inside that number, so the usable floor is smaller than the label suggests.

Outside, the same freezer measures roughly 50 by 30 by 34 inches, which is 51,000 cubic inches, or 29.5139 cubic feet. Just under half of that cabinet, 14.5139 cubic feet, is foam, liner, condenser and compressor. The ratio explains why outside dimensions matter more than the label once a freezer has to pass a doorway or fit under a shelf.

Measure the opening rather than the appliance. A cabinet 30 inches wide needs 31 inches of clear opening once the lid hinge and the door stop are counted, and a basement stair with a 29 inch turn will not take it at any angle without the lid off. Fifteen cubic feet of freezer is a two person lift on a hand truck, and the load is awkward rather than heavy.

Floor load is easy to underestimate. If the contents were water the freezer would carry 935.5 pounds, and spread over the 50 by 30 inch footprint that is 89.8 pounds per square foot. Frozen food is lighter than water, so the real figure lands well below that, but a 15 cubic foot freezer still belongs on a slab or a braced floor rather than a balcony.

A 110 gallon sprayer tank or two rain barrels

Round tanks, height and fill time

Sprayers, water totes and rain barrels are quoted in gallons, and fifteen cubic feet sits just above the common 110 gallon tank. That tank is 110 / 7.48051948051948 = 14.7049 cubic feet, so fifteen cubic feet fills it and leaves 2.21 gallons over. A 150 gallon tank is 20.05 cubic feet and needs a third more volume than this page.

Rain barrels come in pairs for the same reason. Two 55 gallon barrels hold 110 gallons, which is the 14.7049 cubic feet again, and three barrels hold 165 gallons, or 22.0573 cubic feet, which is 47 percent more than fifteen. A single barrel is 7.3524 cubic feet, so fifteen cubic feet is two barrels and a splash, 0.2951 cubic feet short of three.

Fill time depends on the spigot rather than the tank. At 4 gallons a minute from a household faucet, 112.2078 / 4 = 28.05195 minutes fills fifteen cubic feet. A 2 inch transfer pump moving 40 gallons a minute does it in 2.81 minutes, which is the difference between a coffee break and an afternoon.

Round tanks are the shape most people buy, and diameter decides how tall the tank has to stand. The table gives the height a fifteen cubic foot cylinder needs at five diameters, with the gallons each foot of height adds.

The 24 inch row is the one to remember: a drum two feet across has to stand 57.3 inches tall, nearly five feet, to hold fifteen cubic feet. Halve the diameter to 12 inches and the same volume needs 229.2 inches, or nineteen feet of pipe, because area falls with the square of the radius.

Bags of concrete, sand and gravel by the count

25 bags of 80 pound mix, 30 bags of sand

Bag yields are printed on the bag, and the count for fifteen cubic feet follows from them. An 80 pound bag of concrete mix yields about 0.6 cubic feet, so 15 / 0.6 = 25 bags, which is 2,000 pounds of material on the cart and two trips unless the store loads it. A 60 pound bag yields about 0.45 cubic feet, which stretches the same pour to 33.33 bags, and the store sells whole bags, so the order is 34.

Sand and gravel divide the same way with a heavier result. A 50 pound bag of play sand fills about 0.5 cubic feet, so thirty bags make fifteen cubic feet and weigh 1,500 pounds. That is past the 1,000 pound payload of a half ton pickup, so the bags go in two trips, and the wheelbarrow earns its keep on the second one.

Bulk beats bagged above about ten cubic feet. A cubic yard is 27 cubic feet, so fifteen cubic feet is 0.5556 of a yard, and most yards price a part load as a full yard plus a short load fee. That fee is why thirty bags of sand at $5.20 each, or $156, can beat a delivered part yard that bills the same as 27 cubic feet.

A 28 day water reserve for a household of four

One gallon per person per day

The Ready.gov build a kit checklist puts drinking and sanitation water at one gallon per person per day for several days. Fifteen cubic feet is 112.2078 gallons, so a household of four gets 112.2078 / 4 = 28.05 days at that rate, a household of six gets 18.70 days, and one person gets 112.21 days.

Weight decides where the containers live. Fifteen cubic feet of water weighs 935.5 pounds at 62.366 pounds per cubic foot, the USGS Water Science School figure for water at 60 F. Spread across an 8 square foot pallet that is 116.9 pounds per square foot, close to three times the 40 pounds per square foot a wood framed floor is designed for, so the stock belongs on a garage slab or a basement floor.

Keep the containers out of direct sun, write the fill date on each one, and rotate the stock on a schedule you will keep. A pair of 55 gallon barrels covers a couple for 27.5 days and a family of five for 22 days, which is the practical version of this page for anyone who does not want a 112 gallon tank in the garage.

What fifteen cubic feet costs by gallon, bag and yard

One volume, three price lists

Prices arrive in three units, and the conversion is the only way to line them up. At $0.10 a gallon, fifteen cubic feet costs 112.2078 x 0.10 = 11.22 dollars, which is 0.75 dollars per cubic foot and 20.20 dollars per cubic yard at that same rate. The table prices the volume at four rates so a utility bill, a bulk quote and a bag can be compared in one column.

Bagged concrete rarely wins on price. Twenty five bags of 80 pound mix at $6.85 each is $171.25, while the same 0.5556 of a yard as ready mix at $165 a yard is 91.67 dollars of concrete before the short load charge, and that charge usually closes the gap.

Tap water is the exception that makes the rest look expensive. A utility charging $4.20 per 1,000 gallons sells fifteen cubic feet for 47 cents, since 112.2078 / 1,000 x 4.20 = 0.4713. Bottled water at a dollar a gallon turns the same volume into $112.21, which is the real reason a water reserve is built from tap water and food grade containers.

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