Buoyant Force Calculator
Fast, accurate, and free online Buoyant Force Calculator tool that runs directly in your browser.
-
1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
return "Result ready in 0.1s";
}
tools.buoyancy-force calculator.name
tools.buoyancy-force calculator.hint
Rate this tool:
Related tools
Other tools you may find usefulBuoyant force calculator - Archimedes' principle in practice
Do you immerse your body in water and feel that it becomes lighter? This is thebuoyant force- an effect described over two thousand years ago by Archimedes. Our calculator allows you to calculate the value of the buoyant force for a body in a liquid or gas in a few seconds, based on the volume, density of the medium and acceleration due to gravity. You will also find all the necessary formulas, density tables and calculation examples.
Run the buoyant force calculator See formulas and examples
Archimedes' principle - basis of calculations
where Fw- buoyant force [N], ρ - density of liquid or gas [kg/m³], g - acceleration due to gravity [9.81 m/s²], V - volume of the immersed part of the body [m³].
How the calculator works
- Calculates the buoyant force acting on a body in a liquid or gas.
- Gives the apparent weight (the difference between the real weight and the buoyant force).
- Allows you to select the medium - water, oil, alcohol, air, helium and others.
- Supports unit conversions: N, kN, dyn, kgf, lbf.
- Takes into account the temperature and density of water under various conditions.
Density values for common liquids
| Substance | Density [kg/m³] | Temperature [°C] | Remarks |
|---|---|---|---|
| Water | 998 | 20 | Basic reference point |
| Sea water | 1025 | 15 | Higher density - higher buoyancy |
| Vegetable oil | 920 | 20 | Lighter than water |
| Ethyl alcohol | 790 | 20 | Lower density - lower buoyancy |
| Air | 1.2 | 20 | Buoyancy for balloons and gases |
| Helium | 0.18 | 20 | Gas lighter than air |
How to calculate the buoyancy force step by step
- Measure or determine the volume of the immersed part of the body V [m³].
- Select the density of the liquid ρ [kg/m³].
- Substitute the values into the formula Fw= ρ · g · V.
- If you want to know the apparent weight, use: Fpos= Fg− Fw.
Calculation examples
1) Steel cube in water
V = 0.002 m³, ρwater= 998 kg/m³, g = 9.81 m/s²
Fw= 998 × 9.81 × 0.002 ≈ 19.6 N
Buoyant force 19.6 N balances the weight of 2 kg of water. A steel cube with a higher density will sink, but "loses" 19.6 N of its own weight.
2) Block of wood in water
V = 0.005 m³, ρof water= 998 kg/m³, g = 9.81 m/s²
Fw= 998 × 9.81 × 0.005 = 48.9 N
If the density of the wood is 600 kg/m³, its weight is 29.4 N, so the block floats partially - the buoyancy balances the weight when partially submerged.
3) Balloon in the air
V = 0.4 m³, ρarea= 1.2 kg/m³, g = 9.81 m/s²
Fw= 1.2 × 9.81 × 0.4 = 4.71 N
This corresponds to a "weight loss" of 0.48 kg - therefore the helium balloon (density less than air) floats.
4) Substances with different densities
For the same volume of 0.01 m³ and g = 9.81 m/s²:
- Water: Fw= 98.1 N
- Oil: Fw= 90.3 N
- Mercury (ρ = 13534): Fw= 1328 N
The greater the density of the medium, the greater the buoyant force.
Swimming balance
An object floats when its weight balances its buoyant force:
This explains why wood partially floats and ice - despite being denser than water at 0°C - does not sink completely.
Most common applications
- Design of ships, boats and submarines.
- Weather balloons and airships.
- Hydrometers and hydrometers (measuring the density of liquids).
- Calculation of apparent weight in a liquid.
- School experiments with Archimedes in the main role.
FAQ – frequently asked questions
Why does the body seem lighter in water?
Because water exerts an upward buoyant force, which reduces the apparent weight of the body.
Does the buoyant force depend on depth?
No - it only depends on the volume of the submerged part and the density of the liquid, not on how deep the body is.
Is it possible to have buoyancy in gas?
Yes, it is thanks to buoyancy that balloons, dirigibles and smoke float in the air.
What happens if the buoyant force is greater than the weight?
The body floats to the surface and remains partially submerged until the forces balance.
Does temperature affect buoyancy?
Yes - heating a liquid or gas reduces its density, so the buoyancy also decreases.
Summary:The buoyant force is a key physical phenomenon describing the behavior of bodies in liquids and gases. It occurs whenever a body partially or completely immerses itself in a medium, displacing its volume. Knowledge of this law allows us to understand the floating of ships, the floating of balloons and many natural phenomena.
Calculate the buoyant force Check the apparent weight