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Volume Converter

Convert between metric, US customary, and UK imperial volume units (millilitre, cubic centimetre, litre, cubic metre, cubic inch, cubic foot, cubic yard, US fluid ounce, US pint, US gallon, UK pint, UK gallon) with NIST-grade exact factors.

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gal

Result

3.78541 L

1 gal= 3.785412 L

UnitValue
Milliliter (mL)3,785.41
Cubic centimeter (cm³)3,785.41
Liter (L)3.78541
Cubic meter (m³)0.00378541
Cubic inch (in³)231
Cubic foot (ft³)0.133681
Cubic yard (yd³)0.00495113
US fluid ounce (fl oz)128
US pint (pt)8
US gallon (gal)1
UK pint (imperial) (pt (UK))6.66139
UK gallon (imperial) (gal (UK))0.832674

Switching between teaspoons, cups, and grams? Try the cooking converter.

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Volume converter: liters to gallons, milliliters to fluid ounces, and cubic feet.

A volume converter restates a quantity from one unit into another by scaling every unit through the cubic meter. It spans metric, US customary, and UK imperial units, and keeps look-alikes apart — a US gallon is 3.78541 liters while a UK gallon is 4.54609 liters.

What Is a Volume Converter?

1 liter is 0.264172 US gallons, and a US gallon holds 3.78541 liters — but a UK gallon holds 4.54609 liters, roughly a fifth more for the very same word. A volume converter takes a quantity in one unit and restates it in another, routing everything through a single base unit: the cubic meter. Every supported unit stores one factor to the cubic meter, so any pair is only two steps apart — scale the input up to cubic meters, then scale back down to whatever unit you asked for.
That one-pivot design is what lets a single tool move between a splash of milliliters in a recipe, a car's fuel tank in gallons, a swimming pool in cubic meters, and a concrete order in cubic yards without a special rule for each pair. The units group into four families: metric (milliliter, cubic centimeter, liter, cubic meter), the cubic imperial units used for solids and spaces (cubic inch, cubic foot, cubic yard), US customary liquid units (US fluid ounce, US pint, US gallon), and UK imperial liquid units (UK pint, UK gallon). The cubic units nest neatly — 1 cubic foot is 1,728 cubic inches and 1 cubic yard is 27 cubic feet — while a milliliter and a cubic centimeter are simply two names for the identical volume.
Almost every trap here comes from one word meaning two volumes on opposite sides of the Atlantic, and the split is historical. The United States kept the old Queen Anne wine gallon of exactly 231 cubic inches (3.78541 L), while Britain redefined its gallon in 1824 as the volume of ten pounds of water — about 277 cubic inches, or 4.54609 L. That is why a US gallon and a UK gallon differ by about 20%, and why a British "40 miles per gallon" reads as thirstier than it really is once someone treats it as US mpg. The fluid ounce splits the same way (29.5735 mL in the US against 28.4131 mL in the UK), and so does the pint — about 473 mL in a US glass versus about 568 mL in a UK one, because a US pint holds 16 fluid ounces while a UK pint holds 20. The converter labels every US and UK unit by name, so a bare "gallon" never slips through unlabeled.

How to Use the Volume Converter

Using the volume converter takes three steps:
1. Pick the unit you are starting from in the From menu — liter, US gallon, milliliter, cubic foot, or any other supported unit.
2. Pick the unit you want in the To menu.
3. Type your value. The result updates as you type, and you can click it to copy.
Either menu switches to any unit in the list at any time, so you choose both the from-unit and the to-unit yourself rather than being tied to one fixed pair. A precision selector lets you keep the automatic setting or fix the number of decimals, which helps when a factor runs to several places.
To run a conversion by hand, scale through the cubic meter — or, for everyday liquid work, straight through the liter. US gallons to liters: 1 US gallon is 3.78541 liters, so 5 gallons is 5 × 3.78541 = 18.92705 liters. Liters to US gallons reverses it: 1 liter is 0.264172 US gallons, so 20 liters is 20 × 0.264172 = 5.28344 US gallons. Milliliters to US fluid ounces: 1 US fluid ounce is 29.5735 mL, so 250 mL is 250 ÷ 29.5735 ≈ 8.4535 fluid ounces. Whichever pair you pick, it is one scale into the base unit and one scale back out.
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The Volume Conversion Formula

Vt=Vs×fs÷ftV_t = V_s × f_s ÷ f_t
  • VsV_s = The volume you start from, in the source unit
  • fsf_s = Cubic meters in one source unit — its factor to the cubic meter (0.00378541 for a US gallon, 0.001 for a liter)
  • ftf_t = Cubic meters in one target unit — its factor to the cubic meter
  • VtV_t = The converted volume, in the target unit
Every volume conversion is a single multiplication, because all volume units share the same zero: zero of anything is zero cubic meters. Give each unit one number — how many cubic meters it equals — and any pair of units is two scalings apart. Scale the input up to cubic meters with the source factor, then scale back down with the target factor. There is no offset to add, which is what separates a volume conversion from a temperature one.
The metric factors are powers of ten: 1 mL = 0.000001 m³, 1 L = 0.001 m³, and 1 m³ = 1 m³. The cubic imperial units come from the exact inch (1 inch = 0.0254 m), so 1 cubic inch = 0.0254³ = 0.000016387064 m³, 1 cubic foot = 0.3048³ = 0.028316846592 m³, and 1 cubic yard = 0.9144³ = 0.764554857984 m³. The US customary liquid units all hang off one anchor — the gallon, fixed at exactly 231 cubic inches, which works out to 3.785411784 L — so a US pint is a gallon ÷ 8 (0.473176 L) and a US fluid ounce is a gallon ÷ 128 (29.5735 mL). The UK units hang off the imperial gallon, fixed at exactly 4.54609 L since 1985, with a UK pint at a gallon ÷ 8 (0.568261 L).
Unlike some length or temperature scales, there are no rounded units here — every volume factor is an exact legal definition. A US gallon is exactly 231 cubic inches, a UK gallon exactly 4.54609 liters, and a US fluid ounce exactly 29.5735295625 mL. So the only rounding in any result is the number of decimal places you choose to display; raise the precision and the extra digits are already there, never invented. Within a system the relationships stay clean too: 1 US gallon is exactly 128 US fluid ounces, 1 US pint is exactly 16 US fluid ounces, and every metric step is a plain shift of the decimal point.

Common Volume Conversions

ConversionResult
1 liter1000 milliliters
1 liter0.264172 US gallons
1 liter0.219969 UK gallons
1 liter2.11338 US pints
1 US gallon3.78541 liters
1 UK gallon4.54609 liters
1 US gallon128 US fluid ounces
1 US fluid ounce29.5735 milliliters
1 US pint473.176 milliliters
1 UK pint568.261 milliliters
1 cubic meter1000 liters
1 cubic meter264.172 US gallons
1 cubic foot28.3168 liters
1 cubic yard27 cubic feet
1 cubic inch16.3871 milliliters
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Worked Volume Conversions

A fuel tank: 60 liters in gallons

A 60-liter fuel tank is 15.85 US gallons — but only 13.20 UK gallons. Multiply liters by 0.264172 for US gallons: 60 × 0.264172 = 15.85032 US gal. For UK gallons, multiply by 0.219969 instead: 60 × 0.219969 = 13.19814 UK gal. The two answers differ by about 20% from the same 60 liters, which is exactly why a fuel-economy figure is meaningless until you know which gallon it uses.

A water jug: 5 US gallons in liters

A 5-gallon water jug holds 18.92705 liters. Multiply US gallons by 3.78541: 5 × 3.78541 = 18.92705 L. The factor traces straight back to the legal definition — 1 US gallon is exactly 231 cubic inches, and 231 × 16.387064 mL comes out to 3.785411784 L. To reverse it, multiply liters by 0.264172, so 18.92705 L returns to very nearly 5 US gallons.

In the kitchen: 250 mL in US fluid ounces

A 250 mL measure is 8.4535 US fluid ounces. Divide milliliters by 29.5735, since 1 US fluid ounce is 29.5735 mL: 250 ÷ 29.5735 = 8.4535 fl oz. Going the other way, 8 US fluid ounces is 8 × 29.5735 = 236.588 mL. Match the ounce to the recipe's country — a UK fluid ounce is 28.4131 mL, so a British recipe measured in ounces converts on a slightly different factor.

At the bar: a US pint versus a UK pint

A US pint is 473.176 mL (16 US fluid ounces), while a UK pint is 568.261 mL (20 UK fluid ounces) — about 95 mL more beer for the same word. To convert one to the other, divide: 1 UK pint ÷ 1 US pint = 568.261 ÷ 473.176 = 1.201, so a UK pint is 1.201 US pints. That is the same ~20% gap that separates the two gallons, running right down through their pints.

A rainwater tank: 2 cubic meters in gallons

A 2 m³ rainwater tank holds 2,000 liters, which is 528.34 US gallons or 439.94 UK gallons. Multiply cubic meters by 264.172 for US gallons: 2 × 264.172 = 528.344 US gal, and by 219.969 for UK gallons: 2 × 219.969 = 439.938 UK gal. In imperial cubic units the same tank is 2 × 35.3147 = 70.63 cubic feet — handy when a spec sheet lists capacity in cubic feet rather than liters.

Engine size: 350 cubic inches in cc

A 350-cubic-inch V8 displaces 5,735.5 cc, or about 5.7 liters. Multiply cubic inches by 16.387064: 350 × 16.387064 = 5735.5 cm³, and since 1 cm³ equals exactly 1 mL, that is also 5,735.5 mL. Reversing it, a 1000 cc motorbike is 1000 ÷ 16.387064 = 61.02 cubic inches. The "cc" on an engine badge and the "mL" on a measuring jug are the very same unit under two names.

Common Volume Conversion Mistakes

  • Treating a US gallon and a UK gallon as the same. A US gallon is 3.78541 liters, but a UK (imperial) gallon is 4.54609 liters — roughly 20% bigger. It is the most expensive volume mix-up there is: a British car review quoting fuel economy in imperial gallons, or an oil figure copied without checking its nationality, comes out wrong the moment the wrong gallon is assumed.
  • Assuming a fluid ounce is a fluid ounce. A US fluid ounce is 29.5735 mL, while a UK fluid ounce is 28.4131 mL — close, but not equal. Scale a cocktail or a marinade across the ocean without noticing and the ounce-by-ounce errors add up. Match the ounce to the country the recipe came from, and use the converter's US fluid ounce only for US recipes.
  • Forgetting that a milliliter and a cubic centimeter are identical. 1 mL equals exactly 1 cm³ — the same volume under two names, which is also the "cc" on a syringe or an engine badge. There is no factor to apply between them, so treating them as different units only adds a needless step and a chance to slip a decimal.
  • Confusing a US pint with a UK pint. A US pint is 473.176 mL (16 fluid ounces), but a UK pint is 568.261 mL (20 fluid ounces) — the reason a pint of beer poured in a British pub is noticeably bigger than one poured in a US bar. The same 20% gap that separates the two gallons runs right down through their pints.
  • Hunting for a quart or cup button that is not there. This converter lists milliliters, cubic centimeters, liters, cubic meters, the cubic imperial units, and US/UK fluid ounces, pints, and gallons — but not quarts or cups. A US quart is simply 2 US pints or a quarter of a US gallon, so convert through pints or gallons instead: 1 liter is about 2.11338 US pints, and 4 quarts make one US gallon.
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Volume Converter — Frequently Asked Questions

How many liters are in a gallon?

It depends which gallon. A US gallon is 3.78541 liters, while a UK (imperial) gallon is 4.54609 liters — about 20% larger. Always check which one a figure means before converting fuel, recipes, or oil prices.

What is the difference between a US gallon and a UK gallon?

A US gallon is 3.78541 liters and a UK (imperial) gallon is 4.54609 liters, so the UK gallon is roughly 20% bigger. They are two separate units, not roundings of each other, which is why an unlabeled "gallon" is ambiguous in any technical document. A US gallon works out to about 83% of a UK gallon.

Why is the UK gallon bigger than the US gallon?

The two countries froze the gallon at different moments. The US kept the old Queen Anne wine gallon of exactly 231 cubic inches (3.78541 L), while Britain redefined its gallon in 1824 as the volume of ten pounds of water — about 277 cubic inches, or 4.54609 L. Nothing has aligned them since, so the ~20% gap is permanent.

How many milliliters are in a US fluid ounce?

A US fluid ounce is 29.5735 mL. For quick kitchen work the 30 mL shortcut is close enough, but keep the full 29.5735 mL for anything measured precisely. A UK fluid ounce is different again — 28.4131 mL.

Is a milliliter the same as a cubic centimeter?

Yes, exactly. 1 mL equals 1 cm³ — the same volume with two names, so no conversion is needed between them. A dose written in cc and one written in mL are identical amounts.

How do I convert liters to gallons?

Multiply liters by 0.264172 to get US gallons, since 1 liter is 0.264172 US gallons — so 20 liters is 20 × 0.264172 = 5.28344 US gallons. For UK gallons, multiply by 0.219969 instead, because the UK gallon is the larger unit.

How do I convert gallons to liters?

Multiply US gallons by 3.78541, the exact US gallon-to-liter factor: 5 US gallons is 5 × 3.78541 = 18.92705 liters. For UK gallons, multiply by 4.54609 instead, so 5 UK gallons is 22.73045 liters — about 3.8 liters more than five US gallons.

How many fluid ounces are in a gallon?

A US gallon holds exactly 128 US fluid ounces. A UK gallon holds 160 UK fluid ounces, because a UK pint is 20 fluid ounces against the US pint's 16, and both gallons are 8 pints.

What is the difference between a US pint and a UK pint?

A US pint is 473.176 mL and a UK (imperial) pint is 568.261 mL, so the UK pint is roughly 20% larger — the same gap that separates the two gallons. A US pint is 16 fluid ounces while a UK pint is 20, which is why a pint of beer in a British pub is bigger than a pint in a US bar.

How many quarts are in a liter?

One liter is about 1.05669 US quarts — a touch more than a quart. This converter lists US pints and gallons rather than quarts, but the relationship is simple: a US quart is 2 US pints or one-quarter of a gallon, so 1 liter is about 2.11338 US pints, and 4 quarts (3.78541 liters) make a US gallon.

How many gallons are in a cubic meter?

One cubic meter is 264.172 US gallons or 219.969 UK gallons. Since a cubic meter is exactly 1,000 liters, you can also read it as 1,000 liters and apply the usual liter-to-gallon factors. It is the natural unit for tanks, pools, and water-supply figures.

How many liters are in a cubic foot?

One cubic foot is 28.3168 liters, and one cubic meter is 35.3147 cubic feet. Cubic feet turn up on appliance and shipping specs, while liters and cubic meters dominate liquid and construction volumes, so the two families cross often. A cubic yard, higher still, is 27 cubic feet or 764.555 liters.

Can I use this to convert cc to mL for engine size?

Yes. A cubic centimeter (cc) is exactly a milliliter, so engine displacement moves cleanly between cc, mL, and liters — a 1,500 cc engine is 1.5 liters. To reach cubic inches, use the cubic inch unit: 1 cubic inch is 16.3871 cc, so a 350-cubic-inch V8 is about 5,735 cc, or 5.7 liters.

How accurate is this volume converter?

It uses exact legal definitions: 1 US gallon is 231 cubic inches (3.785411784 L), 1 UK gallon is 4.54609 L, 1 US fluid ounce is 29.5735295625 mL, and 1 cubic meter is 1,000 liters. Every volume factor is exact, so the only rounding is in how many decimals you choose to display with the precision selector.

Is this volume converter free?

Yes. It runs entirely in your browser with no account and no limits, covering metric, US customary, and UK imperial units. An embeddable version is available too, so brewing, plumbing, cooking, and engineering sites can host it without sending readers off-site.

出典・参考文献

  1. NIST SP 811 Appendix B.8 — Factors for units listed alphabetically (exact volume factors in boldface: US fluid ounce 2.95735295625e-5 m³, US gallon 3.785411784e-3 m³, cubic foot 2.8316846592e-2 m³, all definitionally exact)
  2. NIST Guide to the SI, Appendix B — Conversion factors (landing page, with the canonical bold-is-exact convention)
  3. BIPM — The International System of Units (SI Brochure, 9th edition 2019): the litre is listed among non-SI units accepted for use with the SI (1 L ≡ 1 dm³ ≡ 0.001 m³, exact)
  4. UK Weights and Measures Act 1985, Schedule 1, Part VI — "GALLON = 4.54609 cubic decimetres"; the binding statutory definition of the imperial gallon in force since 1985
  5. Wikipedia — Gallon: US gallon defined as exactly 231 cubic inches = 3.785411784 L; imperial gallon = 4.54609 L exactly since the 1985 UK Weights and Measures Act; ratio 1 UK gal ≈ 1.20095 US gal (US gal is ~83.27% of UK gal)
  6. Wikipedia — Litre: SI-accepted non-SI unit, defined as 1 L ≡ 1 dm³ ≡ 1000 cm³ since the 1964 CGPM redefinition (replacing the older 1.000028 dm³ mass-based definition); 1 mL ≡ 1 cm³ exactly
  7. Wikipedia — Fluid ounce: US fluid ounce = 1/128 US gallon = 29.5735295625 mL exactly; imperial fluid ounce = 1/160 UK gallon = 28.4130625 mL exactly; US fl oz is ~4.084% larger than the imperial fl oz despite the UK gallon being larger overall
  8. Wikipedia — International Yard and Pound Agreement (1 July 1959): yard defined as exactly 0.9144 m → cubic foot exactly 0.028316846592 m³, cubic yard exactly 0.764554857984 m³, cubic inch exactly 1.6387064e-5 m³

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