Archimedes’ principle explains why ships float and why you feel lighter in water.
How to use the Buoyancy Calculator
- Fluid
- Submerged volume
- Object mass
Results update as you type, and every field accepts the units shown in its menu.
How it works
Multiply the fluid density by the submerged volume and gravitational acceleration.
Inputs explained
| Field | What to enter |
|---|---|
| Fluid | Choose one: Fresh water (1,000 kg/m³), Seawater (1,025), Air (1.225), Mercury (13,534) |
| Submerged volume | Units: m³, L, ft³, yd³, US gal |
| Object mass | Units: kg, lb, g, oz, st |
What each result means
- Buoyant force = [Fluid] × [Submerged volume] × g
- Object weight = [Object mass] × g
- Net upward force = [Buoyant force] – [Object weight]
Example values
How the main result changes when Submerged volume changes and everything else stays at the example values above:
| Submerged volume (m³) | Buoyant force (N) |
|---|---|
| 0.025 | 245.17 |
| 0.0375 | 367.75 |
| 0.05 | 490.33 |
| 0.0625 | 612.92 |
| 0.075 | 735.5 |
| 0.1 | 980.67 |
Formula
F_b = ρ_fluid × V × gWorked example
Inputs — Fluid: Fresh water (1,000 kg/m³); Submerged volume: 0.05 m³; Object mass: 40 kg.
Results — Buoyant force = 490.33 N; Object weight = 392.27 N; Net upward force = 98.07 N.
Frequently asked questions
Why do steel ships float?
Their hollow shape displaces a large volume of water.
Is it easier to float in the sea?
Yes, seawater is denser than fresh water.
What formula does the Buoyancy Calculator use?
F_b = ρ_fluid × V × g.