Convert fl oz to L US fluid ounces ↔ litres Free Online Secure
Type a value in US fluid ounces and read it in litres at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Convert from US fluid ounces
Common values — Convert fl oz to L (US fluid ounces ↔ litres)
| fl oz | L |
|---|---|
| 1 | 0.0295735295625 |
| 2 | 0.059147059125 |
| 3 | 0.0887205886875 |
| 5 | 0.1478676478125 |
| 10 | 0.295735295625 |
| 20 | 0.59147059125 |
| 50 | 1.478676478125 |
| 100 | 2.95735295625 |
Where these units come from
The litre has an awkward history. From 1901 it was defined as the volume of one kilogram of pure water at its densest, which sounds elegant but came out at 1.000028 cubic decimetres — close enough to be confusing and far enough to spoil careful work. In 1964 the definition was abandoned and the litre became exactly one cubic decimetre, which it has been ever since. The gallon has a messier story still: the US gallon descends from the English wine gallon of 231 cubic inches, while Britain redefined its own in 1824 as the volume of ten pounds of water. Nobody reconciled the two, so a US gallon is 3.785411784 litres and an imperial gallon 4.54609 — about a fifth larger. The gallon, pint, cup, fluid ounce and spoons on this page are the US ones.
Where you meet them
Millilitres and litres run through daily life almost invisibly: bottles, fuel, paint, dosage, the capacity of a kettle. Cubic metres belong to water bills, concrete, shipping and the air a ventilation system has to move. Cubic centimetres name engine displacement, cubic feet appear in freight and in appliance capacities, and cups and spoons live almost entirely in recipes — which is exactly where the difference between a US cup and a metric one quietly ruins a cake.
Questions people ask
Is a fluid ounce a measure of weight?
No, it is a measure of volume, even though ounce also names a weight. A US fluid ounce is 29.5735 millilitres; the imperial one is slightly smaller, at 28.4131. The shared name is a historical accident, and for water the two roughly match, since a fluid ounce of water weighs close to an ounce.
Is a litre of water really a kilogram?
Very nearly. The kilogram was first defined as the mass of one litre of water, and the two are still close: water at about 4 °C is 0.99997 kilograms per litre. It is not exact today because the kilogram is now defined from a physical constant. Warm water is slightly lighter, so the rule is a good approximation and not a law.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Nalgene, Hydro Flask and the camp kitchen: outdoor water bottles in litres
Outdoor bottles are sold by the ounce in American shops, 16, 24, 32, 40 or 64, while water filters, stoves and trail guides in most other countries speak of litres. A walker planning a three-day trip across two systems needs to convert fl oz to L: multiply by 0.0295735. A 32 ounce bottle is 0.95 litres, a 64 ounce one 1.89 litres, and a bottle labelled 1 litre is 33.8 ounces. This page multiplies as you type, and the text below goes through bottles, filters, stoves and daily water needs on the trail.
The page covers the rule with examples, a note on each unit, a comparison, a tour of outdoor gear and the slips to avoid. All arithmetic happens in your browser; nothing you enter is sent anywhere. Always follow the instructions that come with water treatment products.
How to convert fl oz to L: multiply by 0.0295735
The rule
One US fluid ounce is 0.0295735296 litres, 29.57 millilitres. To convert fl oz to L, multiply the ounces by 0.02957, or by 0.03 for a quick figure. So 16 oz is 0.473 L, 32 oz is 0.946 L, 40 oz is 1.18 L and 64 oz is 1.89 L. In the other direction, multiply litres by 33.814.
Worked examples
A bottle of 24 ounces holds 0.71 litres. One of 18 ounces holds 0.53. A 100 ounce hydration bladder holds 2.96 litres. A pot of 34 ounces, as in many one-litre stove systems, holds 1.0 litre. For a quick figure, multiply by 3 and move the point.
Why not 0.028
The figure 0.028 is the number of kilograms in an ounce of weight. A fluid ounce is a volume, and the factor to litres is 0.0296. Using 0.028 understates the volume by 5 percent.
A quick sanity check
The litre is the larger unit, so the number shrinks by about thirty-four times. If your “convert fl oz to L” calculation result shrank only eight or sixteen times, you used the cup or pint factor.
The fluid ounce
An eighth of a cup
The fluid ounce is how American outdoor brands label bottles: 12, 16, 18, 21, 24, 32, 40 and 64 ounces are standard sizes. It is a unit of volume, which is not the same thing as the ounce on a scale, though water weighs nearly an ounce for each one.
Where it appears
Bottles, thermoses, bladders and camping cookware.
The litre
A thousand cubic centimetres
The litre is the basis of hiking advice in most countries: half a litre an hour, three litres a day, a one-litre stove pot. It also gives the weight directly, since a litre of water is a kilogram.
Where it appears
Trail guides, filters, stoves, packs and bladders.
Fluid ounce and litre compared
A litre holds nearly 34 fluid ounces. The bottle sizes sold in ounces, 32 and 64, are close to 1 and 2 litres but a few percent short, and a 34 ounce bottle is a true litre. People buying gear online from different countries should check which is meant before assuming a bottle will hold the water they plan on.
The factor is not round, so estimates are approximate: multiply by 3, move the point, and take off 1.5 percent. For exact work use 0.0295735296.
Where the conversion appears
Bottles
Popular wide-mouth bottles come in 16, 24, 32 and 48 ounce sizes, 0.47, 0.71, 0.95 and 1.42 litres. Insulated bottles come in 18, 21, 24, 32, 40 and 64 ounces, 0.53, 0.62, 0.71, 0.95, 1.18 and 1.89 litres. When you convert fl oz to L for a bottle, you can see at once how many you need to carry for a given distance.
Hydration bladders
Bladders are sold in 50, 70 and 100 ounce sizes, 1.5, 2.1 and 3.0 litres. A day hiker usually takes 2 litres, 68 ounces. On a hot day in the desert, advice is up to a gallon a day, 128 ounces, 3.8 litres. Plan the number of refill points along the route as well as the capacity you carry.
Stove pots and cookware
One-litre cooking cups hold 34 ounces and boil enough water for two meals. A smaller 16 ounce cup, 0.47 litres, is enough for a single freeze-dried meal. Pots are marked in ounces or millilitres, and a conversion lets you check whether a pot will boil enough for the group.
Daily water on the trail
A common guide is half a litre an hour of moderate activity, 17 ounces. A five-hour day needs 2.5 litres, 85 ounces, plus cooking water. In hot weather the need can double. Because a litre weighs a kilogram, 3 litres is 3 kilograms, 6.6 pounds, a large share of a day pack, so planners balance carrying and refilling.
Weight of water
An ounce of water weighs 29.57 grams, a litre 1,000 grams, 2.2 pounds. A 32 ounce bottle full weighs 0.95 kilograms, 2.1 pounds. A bladder of 100 ounces weighs 3 kilograms, 6.5 pounds. Because water is the heaviest item for many walkers, converting to litres is also converting to kilograms, and the sum for the pack follows.
In a spreadsheet
Put ounces in column A and use =A2*0.0295735296 in column B. For the reverse, =B2/0.0295735296. A column for hours and a rate of 0.5 gives the litres needed for a trip. Format with two decimals, and keep the source column so that each figure can be traced to the bottle label.
Rounding
The factor is exact, so rounding is your choice. Bottle sizes are nominal: a 32 ounce bottle is 0.946 litres, but the real capacity may be 1.0 litre to the brim. Round the figure to two decimals and plan with a margin. Round water needs up, since it is better to have a little too much than too little.
A mental shortcut
Multiply by 3 and move the point: 24 ounces gives 72, so 0.72 litres, less 1.5 percent, 0.71. For 32 ounces, 96, 0.96, less 1.5 percent, 0.95. For 100 ounces, 3.0, less 0.05, 2.96. The result is within a tenth of a percent, close enough for any trip plan.
Reference values
8 oz is 0.24 L, 16 oz is 0.47 L, 24 oz is 0.71 L, 32 oz is 0.95 L, 34 oz is 1.0 L, 40 oz is 1.18 L, 64 oz is 1.89 L, 100 oz is 2.96 L and 128 oz is 3.79 L. If you convert fl oz to L and land far from this ladder, repeat the multiplication.
Checking by reversing
To make sure your “convert fl oz to L” calculation result is right, multiply it by 33.814. If 24 oz gave 0.71 L, then 0.71 times 33.814 returns 24. A second check is the size of the answer: it should be about thirty-four times smaller. If it is only eight times smaller, you used the cup factor.
Lakes, rivers and where to refill
Topographic guides mark water sources, and a walker works out the distance between them. If the next refill is 15 kilometres away, about four hours, the walker needs two litres, 68 ounces, to arrive comfortably. A bladder of 70 ounces, 2.07 litres, covers it. When you convert fl oz to L for the bladder, you can place it on the water plan at a glance.
Water caches and long routes
On very long trails with dry stretches, hikers sometimes leave water caches in gallon jugs, 128 ounces, 3.79 litres, or bring two to three litres more than usual. A 20 mile dry stretch, 32 kilometres, in warm weather needs about 4 litres, 135 ounces. Trail associations give the distances and the advice in miles and gallons, and travellers from abroad convert both.
Camp sinks and washing
A collapsible camp sink holds 5 to 10 litres, 170 to 340 ounces. Washing dishes for four uses about 4 litres, 135 ounces, and a handwash another litre. Gear catalogues list camp water containers in gallons or litres, such as 2.5 gallons, 9.5 litres, which would serve four people for dishes and handwashing for a weekend.
Sports nutrition powders at camp
A drink mix is made with 16 or 20 ounces of water per serving, 473 or 591 millilitres. A bottle of 24 ounces holds one and a half servings. A three-day trip with two drinks a day needs 6 servings, 96 to 120 ounces, 2.8 to 3.5 litres, of water on top of the drinking water. Packs state the amount in ounces, so a conversion saves a mistake.
Water filters
A squeeze filter fits on a 1 litre pouch, 34 ounces, and filters about 2 litres a minute at best, a pouch in under a minute. A gravity filter holds 4 litres, 135 ounces, in a bag and drips through in a few minutes. Pump filters work at 1 litre per minute. Capacity is given in litres or gallons, and when you convert fl oz to L for a bag marked in ounces, you can estimate how many fills a group needs.
Pack weight and water
Ultralight walkers aim for a base pack weight of 5 kilograms without food and water. Water is the largest variable: 2 litres add 2 kilograms. A route with plentiful streams lets you carry 1 litre, 34 ounces, between sources, a saving of 1 kilogram. The bottle size in ounces on the label becomes the weight in kilograms through the same factor, and so is easy to include in the planning sheet.
Scouts and group trips
A troop of 12 scouts on a weekend trip needs about 3 litres each per day, so 36 litres, 1,217 ounces, 9.5 gallons. Leaders buy a 5 gallon container, 18.9 litres, or two 10 litre cans. They count the bottles in ounces from American outfitters and litres from European ones, and a conversion table taped inside the kit box keeps everyone consistent.
Stoves, fuel and the litre of water
Gas stoves quote boil times for 1 litre, 34 ounces, such as 3.5 minutes. A group of four boiling 2 litres, 68 ounces, for dinner and 1 litre for breakfast uses about 25 grams of gas per litre, 75 grams a day. When you convert fl oz to L for a pot marked in ounces, you can estimate fuel use with the same rule of thumb used by guidebooks written in litres.
Chemical treatment
Chlorine dioxide tablets typically treat 1 litre, 34 ounces, each, with a waiting time of 30 minutes to 4 hours depending on the water. A pot of 2 litres, 68 ounces, takes two tablets. Always follow the instructions on the pack, since concentration and contact time matter more than the unit of measure. Ounces on American packs and litres on European ones describe the same water.
Boiling water
Bringing water to a rolling boil kills most pathogens, and at high altitude a longer boil is advised. A stove with a 1 litre pot, 34 ounces, boils in 3 to 5 minutes. Two litres, 68 ounces, takes twice the fuel. Fuel use is counted in grams of gas per litre of water, so the volume in litres feeds directly into a fuel plan.
Freeze-dried meals
A typical freeze-dried meal calls for 16 ounces of boiling water, 473 millilitres, 0.47 litres. Two people eating together need 32 ounces, 0.95 litres, a litre pot. A trip of three days with dinner and breakfast for two needs 6 meals, 96 ounces, 2.8 litres. The water for meals adds to the drinking water in the plan.
Coffee and tea at camp
A camp mug holds 12 to 16 ounces, 355 to 473 millilitres. A morning coffee for two takes 24 to 32 ounces of water, 0.7 to 0.95 litres, so one litre pot of water boiled serves both. A percolator or a pour-over cone adds to the weight, while instant coffee needs only boiled water. Ounces on the mug and litres on the pot are the two numbers to match.
Winter water
Water bottles freeze in cold weather, so winter walkers carry bottles upside down and insulated, or keep them under their jackets. An insulated 32 ounce bottle, 0.95 litres, keeps liquid warm for 12 hours. Hot drink in a 24 ounce flask, 0.71 litres, fills three mugs. Winter planning counts litres of snow melted, since melting 1 litre needs more fuel than boiling it.
Kayaks and canoes
Paddlers carry water in bottles stowed within reach, and larger containers in the hull. A drinking bag of 100 ounces, 3 litres, and a bottle of 32 ounces serve a day. On the water a boat is a hazard in itself, and you drink much without noticing, so plan the same rate as on land, or a little more. The amounts in litres are the same everywhere.
Water for children and dogs
A child of 8 needs about 0.3 to 0.5 litres an hour on a walk, 10 to 17 ounces. A dog of 20 kilograms needs 0.5 to 1 litre a day, 17 to 34 ounces, and a collapsible bowl holds 12 ounces. A family of four with a dog planning a day walk of five hours needs about 9 litres, 300 ounces. Carrying that means two large bladders and a few bottles.
More values for convert fl oz to L
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 fl oz = 0.00295735 L
- 0.5 fl oz = 0.0147868 L
- 3 fl oz = 0.0887206 L
- 4 fl oz = 0.11829411825 L
- 7 fl oz = 0.207015 L
- 15 fl oz = 0.443603 L
- 20 fl oz = 0.59147059125 L
- 75 fl oz = 2.21801 L
- 200 fl oz = 5.9147059125 L
- 500 fl oz = 14.78676478125 L
- 2,000 fl oz = 59.147059125 L
- 10,000 fl oz = 295.735295625 L
Mistakes when you convert fl oz to L
Mixing fluid and weight ounces
A fluid ounce is 29.57 ml, an ounce of weight 28.35 g. Use the fluid one for water.
Assuming 32 ounces is a litre
A 32 ounce bottle is 0.946 litres. A litre is 33.8 ounces.
Multiplying by 33.8
That goes from litres to ounces. From ounces to litres, multiply by 0.0296.
Gear-shop questions
What does one fluid ounce come to in litres?
Roughly 0.0296 of a litre.
What is the quick way to convert fl oz to L?
Multiply the ounces by 0.0296.
And a litre in fluid ounces?
Roughly 33.8.
How much is a 32 ounce bottle?
A little under a litre, 0.946.
Do my numbers leave the page?
No, the sum is done inside your browser.
Keep going on the trail of conversions
Nearby volume converters: Convert fl oz to ml, Convert fl oz to cups, Convert gal to L, Convert cm³ to L, Convert L to m³, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. For the return direction, open Convert L to fl oz.
Bottom line: to convert fl oz to L, multiply by 0.0296 and keep the unit next to the number. The figure never leaves your device, and there is no account or upload.