Fluid Ounces to Pounds Converter
Convert US fluid ounces to pounds and other mass units — select a substance or enter a custom density (g/mL) to account for the liquid's weight.
fl oz (US)
Substance
Mass of the selected substance at the given volume
- 1
Volume in millilitres
16 × 29.5735 = 473.181 US fluid ounce = 29.5735 mL exactly (NIST definition). - 2
Mass in grams
473.18 × 1 = 473.176 - 3
Convert to pounds
473.176 ÷ 453.592 = 1.0432
How does this calculator work?
Mass (lb) = fl oz × 29.5735 × density (g/mL) ÷ 453.592. For water (1.000 g/mL), 1 US fl oz ≈ 0.0652 lb. Denser liquids weigh more per fl oz; select a substance or enter a custom density in g/mL for any liquid. Uses the US fluid ounce (29.5735 mL), not the imperial fl oz.
Formula
How this is calculated
Fluid ounces measure volume, not mass, so converting to weight always requires a density. One US fluid ounce equals exactly 29.5735 mL (NIST definition). Multiplying by the substance's density in g/mL gives mass in grams; dividing by 453.592 converts to pounds, and by 28.350 for avoirdupois ounces.
For water at standard conditions (density = 1.000 g/mL), 1 US fl oz weighs 29.574 g ≈ 1.043 oz ≈ 0.0652 lb. Denser liquids weigh proportionally more — honey at 1.42 g/mL weighs 42 % more per fluid ounce than water; lighter liquids like gasoline (0.737 g/mL) weigh less. Select "Custom density" to handle any substance whose density you know.
Note that the US fluid ounce (29.5735 mL) differs from the imperial fluid ounce (28.4131 mL) — this calculator uses the US definition. Tabulated densities are approximate values at around 20 °C and standard atmospheric pressure; actual density varies with temperature, pressure, and composition.
Frequently asked questions
16 US fl oz × 29.5735 mL/fl oz × 1.000 g/mL ÷ 453.592 g/lb ≈ 1.043 lb. A US pint of water is close to one pound but not exactly — the old "a pint's a pound" saying was based on the imperial system where the numbers happen to align better.
Fluid ounces measure volume — how much space the liquid occupies. Weight (mass) depends on how much matter is packed into that space, which is density. Equal volumes of different liquids have very different weights: a fluid ounce of honey weighs about twice as much as a fluid ounce of gasoline.
A US fluid ounce (fl oz) is a volume unit equal to 1/128 US gallon = 29.574 mL. An avoirdupois ounce (oz) is a mass unit equal to 1/16 pound = 28.350 g. They are numerically close for water (1 fl oz ≈ 1.043 oz by weight) but diverge for denser or lighter liquids.
Also known as
TG we-Calculate Editorial Team. (2026). Fluid Ounces to Pounds Converter [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/fluid-ounces-to-pounds-conversion-calculator
TG we-Calculate Editorial Team. "Fluid Ounces to Pounds Converter." TG we-Calculate. 2026. https://we-calculate.com/calculator/fluid-ounces-to-pounds-conversion-calculator.
TG we-Calculate Editorial Team, "Fluid Ounces to Pounds Converter," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/fluid-ounces-to-pounds-conversion-calculator
@misc{wecalculate_fluid_ounces_to_pounds_conversion_calculator, title = {Fluid Ounces to Pounds Converter}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/fluid-ounces-to-pounds-conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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