Example 1
ρ = 1000, V = 0.001 m³, blank g → F ≈ 9.81 N.
Buoyancy calculator
Type fluid density ρ [kg/m³] and submerged volume V [m³]. The calculator computes F = ρ V g: 1000 kg/m³ and 0.001 m³ is about 9.81 N. Blank g [m/s²] is 9.81.
Density: ρ = m/V. Pressure from depth: p = ρ g h.
Result
Liquid density ρ (kg/m³), Submerged volume V (m³) and g (m/s², optional). The result shows up here.
How it works
Buoyancy F = ρ V g is the weight of the displaced fluid. Water ρ = 1000 kg/m³ and V = 0.001 m³ (a liter) give F = 9.81 N. 0.002 m³ is 19.62 N. 0.05 m³, fifty liters, is about 491 N. 0.5 m³ is 4905 N. 0.00001 m³ (10 ml) is about 0.098 N. Oil at ρ = 900 and a liter give 8.83 N. Seawater 1025 kg/m³ and 0.01 m³ give about 101 N.
V is the submerged part, not the whole solid if the object floats and sticks out. Compare F with weight mg: when F > mg it rises; when F < mg it sinks until V grows or it hits the bottom. ρ is the fluid density, not the solid. Density of the object is on the density page, ρ = m/V.
Fields: ρ in kg/m³, V in m³, empty g = 9.81. Result in newtons. 1 liter is 0.001 m³. A thousand liters is 1 m³. A comma and a period are the same V: 0,001 and 0.001. Typed 0 in ρ or V gives F = 0. ρ and V both need a number before 9.81 N can appear.
Column pressure lives on hydrostatic pressure: p = ρ g h in pascals, from depth, not from volume. Here the result stays the upward force. The same water at 10 m is about 98 kPa, and a liter is still 9.81 N of buoyancy.
The model is Archimedes at rest. Current, waves, and viscosity stay outside the product. You can type g if the problem leaves Earth. Empty g stays at 9.81.
Type 1000 and 0.001, click Calculate, and match 9.81 N. Then 0.05 and see about 491 N. The header symbol does not lift the block.
How to use
- Type fluid ρ, for example 1000 for water or 1025 for seawater.
- Type V in m³, the submerged part. A liter is 0.001. Fifty liters is 0.05.
- Leave g blank for Earth (9.81), or type another value from the problem.
- Click Calculate. 1000 and 0.001 give 9.81 N. 1000 and 0.05 give about 491 N.
- For p = ρ g h, open hydrostatic pressure. ρ = m/V is on the density page.
Formula
F = ρ · V · g
Default g = 9.81 m/s2. V is the submerged volume.
F, ρ, and V in an Archimedes push
Buoyancy here is F = ρ V g. 1000 kg/m³ and 0.001 m³ is about 9.81 N. V is submerged, ρ is the fluid, not the object.
- F
- Buoyant force [N]. 1000 × 0.001 × 9.81 = 9.81 N. Weight of the displaced fluid.
- ρ
- Fluid density [kg/m³]. 1000 for water. Not the block density.
- V
- Submerged volume [m³]. 0.001 is a liter. The whole solid only if it sinks fully.
- g
- Optional 9.81 m/s². A blank field takes the Earth model.
Real-life examples
Example 2
V = 0.05 m³ in water.
Example 3
V = 0.002 m³.
Example 4
ρ = 900, V = 0.001 m³.
Example 5
ρ = 1025, V = 0.01 m³.
Example 6
V = 0.001 m³, g entered.
Example 7
V = 0.5 m³.
Example 8
V = 0.00001 m³.
Example 9
V = 0.001 m³, g = 1.62.
Example 10
V = 0.0004 m³ in water.
Ways to use this calculator
- You compute buoyancy of a liter of water: 0.001 m³.
- You compare F with weight mg, whether a block sinks.
Frequently asked questions
How much F at 1000 kg/m³ and 0.001 m³?
Buoyant force is 9.81 N. That is 1000 × 0.001 × 9.81. Weight of a liter of water, not a whole lake.
Is V the whole object volume?
No. V is the submerged part. If the object floats, V is smaller than the whole solid. The field does not ask for the dry part.
Which units do I type?
Density ρ [kg/m³], volume V [m³], optional g [m/s²]. Result F [N]. Type 1 L as 0.001, not as 1.
How much at 0.05 m³ in water?
You get about 491 N. 0.5 m³ is 4905 N. 0.00001 m³ is about 0.098 N.
How is this different from p = ρ g h?
Here a force in newtons from submerged volume. There pressure in pascals from depth. 10 m of water is about 98 kPa.
Do I have to type g?
No. Blank g = 9.81 m/s². Type g when the problem leaves Earth. Otherwise leave it blank.
How much at ρ = 900 and 0.001 m³?
Force is about 8.83 N. At 1025 kg/m³ and 0.01 m³ you get about 101 N.
Does a comma in 0.001 work?
Yes. 0.001 and 0,001 are the same V [m³]. A comma and a period mean the same value.
Where is ρ = m/V?
On the density page. Here fluid ρ is an input to F = ρ V g, not the object mass.
How many m³ is 1 liter?
0.001 m³. A thousand liters is 1 m³. Typed 1 in water would give 9810 N, tonne order, not a liter.
Knowledge sources
The formula is the school one. Units follow SI; NIST SP 330 and BIPM define the measures, not your result.
Page updated in 2026.