Buoyancy Calculator
A 2 litre object under fresh water feels an upward buoyant force of 19.6133 N, equal to the weight of the 2 kg of water it displaces.
Fresh water 1000 kg/m³, sea water about 1025 kg/m³, air about 1.2 kg/m³.
19.6133 N
Full answer, then cut to fewer decimals (not rounded):
- 19.6133 N
- 19.613 N
- 19.61 N
- 19.6 N
- In kN
- 0.0196133 kN
- In mN
- 19613.3 mN
- In lbf
- 4.409245244 lbf
- In kgf
- 2 kgf
- In dyn
- 1961330 dyn
- Mass of displaced fluid ρV
- 2 kg
Step-by-step solution
- F_b = ρ × V × g
- F_b = 1000 × 0.002 × 9.80665
- F_b = 19.6133 N
Buoyancy Formula
F_b = ρ V g
ρ density of the fluid (not the object), V displaced volume, g gravitational acceleration
Worked Example
A 2 litre object fully submerged in fresh water:
- F_b = ρ × V × g
- F_b = 1000 × 0.002 × 9.80665
- F_b = 19.6133 N
In mN: 19613.3 mN · In lbf: 4.409245244 lbf · In kgf: 2 kgf · In dyn: 1961330 dyn · Mass of displaced fluid ρV: 2 kg
Apparent weight
An object weighed under water seems lighter by exactly the buoyant force. Weighing in air and in water gives the volume, and so the density, which is how Archimedes is said to have tested the king’s crown.
More Fluids, Pressure and Density Calculators
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Pressure Calculator
P = F / A
P pressure (Pa = N/m²), F force normal to the surface, A area
Example: A 500 N force spread over 0.01 m² (10 cm × 10 cm): Pressure P = 50000 Pa.
-
Density Calculator
ρ = m / V
ρ density, m mass, V volume; specific gravity = ρ / ρ(water)
Example: A 2.7 kg block with a volume of 1 litre (0.001 m³): Density ρ = 2700 kg/m³.
Frequently asked questions
Will it float?
Compare the object’s weight with the buoyant force when fully submerged, or simply its density with the fluid’s: less dense objects float.
Why do ships float though steel sinks?
The hull encloses air, so the ship’s average density is below water’s. It sinks until the displaced water weighs as much as the ship.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Buoyancy Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/buoyancy-calculator/
IEEE
Scientific Converters, "Buoyancy Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/buoyancy-calculator/