What is CCF, and why convert it to gallons?
CCF stands for "hundred cubic feet" (C is the Roman numeral for 100). It is the standard billing unit used by most U.S. natural gas utilities and many municipal water utilities, because gas and water meters are calibrated to measure volume in cubic feet. Gallons, on the other hand, are the everyday U.S. unit people use to picture water volume — a hot water heater, a bathtub, or a swimming pool are usually described in gallons, not cubic feet. Converting CCF to gallons lets you translate a utility bill's metered usage into a volume you can actually visualize and compare against household water use or tank capacity.
The exact formula
The conversion relies on two fixed, exact definitions: 1 CCF = 100 cubic feet, and 1 U.S. liquid gallon = 231 cubic inches exactly. Since 1 cubic foot = 12³ = 1,728 cubic inches, one cubic foot equals 1,728 ÷ 231 = 7.4805194805... gallons (a repeating decimal, commonly rounded to 7.48052 or 7.481). Multiplying through:
Gallons = CCF × 100 × 7.480519481 = CCF × 748.0519481
So 1 CCF = 748.05 gallons (rounding to two decimal places). This calculator applies that exact factor directly — there is no estimation, rounding table, or scenario adjustment involved; it is pure dimensional conversion.
Reference values
- 1 CCF = 100 cubic feet = 748.05 gallons
- 1 cubic foot = 7.480519481 gallons
- 10 CCF (a typical monthly gas-heating bill amount in winter) = 7,480.52 gallons-equivalent of volume
- 1 gallon = 231 cubic inches (exact, by U.S. legal definition)
- 1 MCF (thousand cubic feet, sometimes used for gas) = 10 CCF = 7,480.52 gallons
Where you'll see CCF on a bill
Natural gas utilities meter the gas that flows through your line in cubic feet, then bill in CCF (or sometimes therms, which factor in heat content). Water utilities in many U.S. cities also bill in CCF, so a "used 5 CCF this month" line item on a water bill means the household used approximately 5 × 748.05 = 3,740.26 gallons. Converting to gallons makes it far easier to sanity-check usage against typical household consumption benchmarks, most of which are published in gallons rather than cubic feet.
Worked examples
Example 1: A water bill shows usage of 8 CCF. Gallons = 8 × 748.0519481 = 5,984.42 gallons.
Example 2: A gas furnace's supply line delivered 2.5 CCF overnight. Gallons-equivalent volume = 2.5 × 748.0519481 = 1,870.13 gallons (useful for volume comparisons, though gas is typically better tracked by energy content in therms).
Example 3: A commercial account used 150 CCF in a billing cycle. Gallons = 150 × 748.0519481 = 112,207.79 gallons.
Frequently asked questions
Is CCF the same as 100 gallons? No. CCF measures 100 cubic feet, a much larger volume than 100 gallons — 1 CCF equals about 748 gallons, roughly 7.5 times more than 100 gallons.
Why isn't the conversion a round number? Because the cubic foot and the U.S. gallon come from two different measurement systems (cubic length units versus a historically defined liquid-volume unit). The gallon was fixed by U.S. law at exactly 231 cubic inches, which does not divide evenly into a cubic foot's 1,728 cubic inches, so the ratio 1,728/231 is a repeating decimal.
Does this differ for the U.K. or Imperial gallon? Yes. This calculator uses the U.S. liquid gallon (231 in³). The Imperial gallon used in the U.K. and Canada is larger (about 277.42 in³), so 1 CCF equals about 623.2 Imperial gallons instead of 748.05 U.S. gallons.
Why do gas bills sometimes use therms instead of CCF? Therms measure heat energy content, which varies slightly by gas composition, while CCF measures raw volume. Many utilities print both CCF (metered volume) and therms (billed energy) on the same statement.
How many gallons are in an MCF? An MCF (1,000 cubic feet) is 10 CCF, so it equals 10 × 748.0519481 = 7,480.52 gallons.