Buoyancy calculator
Archimedes' principle: the upward force equals the weight of fluid displaced.
L
kg/m3
kg/m3
Buoyant force
98.0665N
- Weight in air
- 68.646 55
- Apparent weight in the fluid
- -29.419 95
- It floats
- 1
- Fraction submerged when floating
- 70.00 %
- Extra mass it could carry and still float
- 3
Show the working
- Volume of the object = 10
- Density of the object = 700
- Density of the fluid = 1000
- v_m3 = 10 / 1000 = 0.01
- mass = 0.01 * 700 = 7
- Weight in air = 7 * g0 = 68.6466
- Buoyant force = 0.01 * 1000 * g0 = 98.0665
- Apparent weight in the fluid = 68.6466 - 98.0665 = -29.42
- It floats = 700 < 1000 ? 1 : 0 = 1
- Fraction submerged when floating = 1000 > 0 ? min(700/1000, 1) * 100 : 0 = 70
- Extra mass it could carry and still float = max(98.0665 - 68.6466, 0) / g0 = 3
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- buoyant force = volume displaced x fluid density x g
- fraction submerged = object density / fluid density
Ice at 917 kg/m3 in seawater at 1025 floats with 89.5% of its volume below the surface.