20 liters is 5.2834410472 US gallons

The US liquid gallon is fixed at 231 cubic inches, and one cubic inch is 16.387064 mL, so a gallon is 3.785411784 L. Twenty liters divided by that figure gives 5.2834410472 US gallons. NIST Handbook 44, Appendix C (2024 edition) lists the 231 cubic inch gallon next to its metric equivalent, and the BIPM SI Brochure (9th edition, 2019) defines the liter as a cubic decimeter.

20 L = 20 / 3.785411784 = 5.2834410472 US gallons

Multiplication works just as well: 20 x 0.2641720524 = 5.2834410472. The same quantity is 20,000 mL, 20,000 cubic centimeters, 1,220.4749 cubic inches and 0.02 cubic meters. Break the answer into whole gallons and the remainder is 0.2834410472 gallon, or 36.2805 fluid ounces, so 20 L is 5 gallons plus a little over 36 ounces.

If you only need a shopping estimate, 20 L is a hair above 5.25 gallons and a hair below 5.3. The exact figure belongs on a mix sheet or an invoice, where a few ounces of concentrate or paint can change the price of a job.

A 20 liter jerry can holds 1.07 liters more than a 5 gallon bucket

The 20 L jerry can and the 5 gallon bucket are the two containers that show up most often beside each other, and they are not the same size. Five US gallons is 18.92705892 L, so a 20 L can carries 1.07294108 L more, a lead of 5.669 percent. In fluid ounces the surplus is 36.28 oz, roughly a quart and a splash.

Go the other way and 20 L is 2.7124707 L short of a 6 gallon jug. The can sits between the two standard bucket sizes, closer to the 5 gallon pail.

The difference matters once a job is priced per gallon. Paint, fuel treatment and cleaner are all sold by the US gallon, so a 20 L can of any of them is billed as 5.2834 gallons. Round that to 5.25 and you undercount by 4.28 fl oz; round to 5.3 and you overcount by 2.12 fl oz. Neither error is large, but the exact 5.2834 is the only figure that reconciles a can count with a gallon invoice.

What a full 20 liter can weighs, and how to lift it

Water is close to 1 kg per liter at room temperature, and the USGS Water Science School puts the peak density at 0.9998395 g per mL near 4 degrees Celsius. A full 20 L can of water is therefore about 20 kg, or 44.0925 lb. Add a steel jerry can at roughly 4 kg and the load is near 53 lb, which is more than most people want to carry up a ladder.

Warm water weighs less. The same USGS page records a gallon of tap water at 70 degrees Fahrenheit at 8.329 lb, so 20 L of warm water is 44.01 lb, about 0.09 lb under the cold figure. The capacity conversion does not care about temperature; only the mass changes.

Fuel is lighter than water. Gasoline runs near 0.74 kg per L, so 20 L is about 32.63 lb, and a full can is a one hand carry for most adults. Diesel at roughly 0.84 kg per L comes to 37.04 lb. Neither figure changes the 5.2834 gallon answer, which is a capacity, not a weight.

Twenty liters of paint covers about 1,849 square feet

Paint coverage is usually quoted at 350 square feet per gallon per coat, a rule of thumb that assumes a smooth, primed wall. At 5.2834 gallons, 20 L covers about 1,849.2 square feet in one coat. Two coats drop the same can to 924.6 square feet, because the second pass uses the same amount of paint again.

Translate that into a room. A 12 by 15 foot room with 8 foot ceilings has 432 square feet of wall, less 40 square feet for a door and two windows, so 392 square feet. One 20 L can puts two coats on that room and still leaves paint for the trim and a second bedroom closet. A larger open plan space of 1,200 square feet of wall takes 1.30 cans at two coats.

The 350 figure is a planning guide, not a promise. Bare drywall, textured plaster and deep color changes all absorb more, and a roller wastes more than a sprayer. Buy 10 percent extra and keep the receipt; a partial can is easier to return than a second trip to the store. The calculator on this page converts any liter figure to gallons and applies the same 350 square foot assumption.

Quarts, pints, cups and ounces at 20 liters

A quart is one quarter of a gallon, so 20 L is 21.1338 quarts. Fluid ounces are the next stop down: 128 of them make a gallon, which puts 20 L at 676.2805 fl oz. Both figures are US liquid units. The imperial quart is larger, so a UK recipe that calls for quarts will not match these numbers without a second conversion.

The ladder below moves one liter at a time. Every row divides by the same 3.785411784, so each step adds 0.2641720524 gallon. The 5 gallon mark falls between 18 L and 19 L, and the 5.25 gallon mark falls just under 20 L.

For cooking, two decimal places are plenty: 20 L is 5.28 gallons or 21.13 quarts. For a fuel mix or a chemical dose, keep at least four: the difference between 5.28 and 5.2834 is 0.0034 gallon, which is 0.44 fluid ounce. That is small in a bucket and large in a two stroke engine.

Imperial gallons: 20 liters is 4.3994, not 5.28

Britain and Ireland use a larger gallon. The Weights and Measures Act 1985, Schedule 1 defines the imperial gallon as exactly 4.54609 cubic decimeters, so 20 L divided by 4.54609 is 4.3993850 imperial gallons. The US answer is 5.2834410, about 20 percent higher for the same can.

The two factors are easy to mix up on a label printed for export. A drum marked 5 imperial gallons carries 22.7305 L, which is 6.005 US gallons. A can marked 20 L is 4.399 imperial gallons and 5.283 US gallons. Neither reading is wrong; they answer different questions.

Canada, Australia and New Zealand have used the liter for retail fuel and milk for decades, but older equipment and imported containers still carry imperial markings. When in doubt, look for the word imperial on the label. If it is missing, the country of sale is the next best clue, and the NIST unit conversion page lists both gallon factors with the current edition of SP 811.

Two stroke mix and the 50 to 1 ratio at 20 liters

Small engines specify fuel to oil ratios, and the ratio is a ratio of volumes, so the unit cancels as long as both sides use the same one. At 50 to 1, a 20 L can of gasoline needs 392.16 mL of two stroke oil, which is 13.26 US fluid ounces. At 40 to 1 the same can takes 487.80 mL, or 16.49 fl oz.

Most owners measure oil in fluid ounces, not milliliters, so the conversion matters. One US fluid ounce is 29.5735295625 mL, and a typical 2.6 fl oz container is 76.9 mL. For a 50 to 1 mix in a 20 L can you need about five of those containers, or one 13 oz container, which is 384.5 mL, still 7.7 mL short of the target.

Do not use the gallon figure to buy oil. The mix ratio is tied to the fuel load, and 20 L is 20 L whether the can is marked in liters or gallons. If a chart is written for 5 gallons, that is 18.9271 L, which is 1.0729 L less than a full 20 L can. Mixing for 5 gallons and pouring into 20 L gives a slightly lean mix, which is the direction that damages a two stroke engine.

The same can feeds a push mower, a string trimmer, a chainsaw and a small outboard, and each engine has its own fuel reservoir. A trimmer with a 0.5 L reservoir would take 40 fills from one 20 L can at 50 to 1, while a chainsaw with a 0.4 L reservoir would take 50. Keep the oil container with the can and mark the ratio on the cap, because a can that has held 40 to 1 mix should not be topped up for a 50 to 1 engine without a note.

Coolers, aquariums and other containers sold as 20 liters

A 20 L cooler is 5.2834 US gallons, which is enough ice and drinks for a small group but not a full day for a family. Campers who plan by the gallon should treat it as a 5 gallon cooler with a little headroom, since the lid and the drain take up space that the nominal capacity ignores.

Cooler ratings are nominal, and the ice-to-drink ratio decides how many people a 20 L cooler serves in practice. A common rule is one pound of ice per person plus the drinks, and ice melts into water at close to 1 kg per L. Fill the cooler half with ice and half with cans and the usable drink capacity drops to about 10 L, or 2.64 gallons. That is a realistic target for a tailgate, and it is lower than the label suggests.

Bottled water is the other way people meet 20 L. A case of 24 half liter bottles is 12 L, so 20 L is 1.67 cases, or 40 single bottles. A 5 gallon office cooler jug is 18.9271 L, so a 20 L delivery is one jug plus 1.07 L, which is why a dispenser route bills the extra liter rather than a second jug.

Aquariums use the same arithmetic. A 20 L aquarium carries 5.283 US gallons or 4.399 imperial gallons of water, and the water alone weighs 44.09 lb. Add gravel at roughly 1.5 kg per L of substrate and the stand has to carry well over 60 lb. Tank capacity ratings usually measure the outside dimensions, so the usable water capacity is a little lower than the label.

Gravel for the same aquarium is sold by the bag and by weight. A 20 L pail of aquarium gravel at about 1.5 kg per L weighs 30 kg, or 66.1 lb, which is more than the water it displaces. Sand runs heavier still. Buy substrate by the bag size printed on the label and check the pound figure on the shelf tag before you plan the stand.

Camping carriers use the same figure. A 20 L water carrier with a spigot and a wide mouth weighs 20 kg when filled, so it belongs on a picnic table or a tailgate, not on a strap over a shoulder. Drain it before the drive home, because a half full carrier sloshes and a full one strains the handle.