Cubic Feet to liters
1 ft³ = 28.3168 L, derived from exact unit definitions.
| ft³ | L |
|---|---|
| 1 ft³ | 28.32 L |
| 2 ft³ | 56.63 L |
| 5 ft³ | 141.58 L |
| 10 ft³ | 283.17 L |
| 25 ft³ | 707.92 L |
| 50 ft³ | 1,415.84 L |
| 100 ft³ | 2,831.68 L |
liters = cubic feet × 28.316846592Exact and terminating. 1 ft = 0.3048 m exactly, so 0.3048³ = 0.028316846592 m³, and a cubic metre is exactly 1,000 litres.How to convert cubic feet to liters
Multiply by 28.316846592. Every digit is exact — this is another conversion where the only judgement call is where to stop writing.
- Get the volume in cubic feet from internal dimensions.
- Multiply by 28.316846592.
- Check the magnitude: litres should be about 28 times the cubic-foot figure.
A cubic tank, 4 ft on each side
- Volume: 4 × 4 × 4 = 64 ft³
- 64 × 28.316846592 = 1,812.278…
- Round to 1,812 L
64 ft³ = 1,812 L
A 4 ft × 10 ft horizontal cylinder, in metric
- Volume: π × 2² × 10 = 125.664 ft³
- 125.664 × 28.316846592 = 3,558.2 L
- = 3.558 m³
125.66 ft³ = 3,558 L
Rainwater: 100 cubic feet of collected runoff
- 100 × 28.316846592 = 2,831.68 L
- Also 2.832 m³, or 748.05 US gal
100 ft³ = 2,831.7 L
Water utilities in the US commonly bill in units of 100 cubic feet — “CCF” or “HCF”. One CCF is 2,831.7 litres or 748.05 gallons, which is worth knowing when a metric consumption figure has to be reconciled against a US water bill.
Where the factor comes from
1 inch ≡ 2.54 cm (1959 Yard & Pound Agreement)
1 foot = 12 × 0.0254 = 0.3048 m exactly
1 ft³ = 0.3048³ = 0.028316846592 m³ exactly
1 m³ = 1000 L (litre ≡ 1 dm³)
∴ 1 ft³ = 28.316846592 L exactlyNIST SP 811 prints foot → metre as 3.048 E-01 in boldface, marking it exact. The cube of an exact value is exact, so this factor carries no uncertainty.Rounding
28.3168 is accurate to 0.0000016 % — more than anyone needs. 28.32 is 0.011 % high; 28.3 is 0.06 % low. Even the crudest of these is smaller than the error in a tape-measured tank, so pick whichever is convenient and spend the attention on the measurement instead.
FAQ
How many liters are in a cubic foot?
Exactly 28.316846592 L. The foot is defined as exactly 0.3048 m, and a cubic metre is exactly 1,000 litres, so the factor is exact and terminates.
Is 28.32 accurate enough?
Almost always. It is 0.011 % high — about 0.3 litres on a 100-cubic-foot tank, far less than the error in measuring the tank.
What is a CCF on a water bill?
One hundred cubic feet: 2,831.7 litres, or 748.05 US gallons. Many US water utilities bill in CCF (sometimes HCF) rather than gallons.
Why is the factor exact when the gallon-to-litre one isn't obviously so?
Both are exact. The foot and the inch were fixed against the metre by the 1959 International Yard and Pound Agreement, and the litre is fixed against the cubic metre by the SI. Any conversion built only from definitions is exact — what varies is whether the decimal happens to terminate.
Sources and standards
Every factor on this page is traced to the document that defines it. Where a value is exact, it is exact because the cited standard makes it so — not because we rounded it well.
- Refinement of Values for the Yard and the Pound — Federal Register Doc. 59-5442 (24 FR 5348, 1 July 1959)National Bureau of Standards; scan hosted by NOAA's National Geodetic Surveyhttps://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdfThe International Yard and Pound Agreement, signed by the United States, United Kingdom, Canada, Australia, New Zealand and South Africa. Fixes the yard at exactly 0.9144 m, from which the inch follows as exactly 25.4 mm. Every inch-to-metric volume factor on this site descends from this one page.
- The International System of Units (SI), 9th edition (SI Brochure)Bureau International des Poids et Mesures (BIPM)https://www.bipm.org/en/si-brochure-9The defining document for the SI, maintained by the treaty organisation that owns the definitions. The litre is exactly one cubic decimetre — 10⁻³ m³ — and is a unit accepted for use with the SI rather than an SI unit itself.
- Special Publication 811, Appendix B.8 — Factors for Units Listed AlphabeticallyNational Institute of Standards and Technologyhttps://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8NIST's master table of conversions into SI. Factors printed in boldface are exact by definition rather than measured or rounded — which is how you tell a defined unit from an approximated one.
- Unit Conversion — Office of Weights and MeasuresNational Institute of Standards and Technologyhttps://www.nist.gov/pml/owm/metric-si/unit-conversionNIST's index page explaining which of its publications governs which kind of conversion: SP 811 for exact factors, Handbook 44 Appendix C for trade and commerce, Handbook 133 Appendix E for packaged goods.
Every linked source above was retrieved and checked on 2026-09-02. Factors quoted as exact are exact by definition in the cited document, not rounded by us.