Buoyancy Calculator
Calculate the buoyant force on any submerged object using Archimedes’ principle (F = ρ · V · g). Enter the submerged volume and fluid density, choose a gravity preset, and the buoyancy calculator computes the buoyant force, displaced fluid mass, and — when you add the object mass — whether it floats or sinks. All calculations run locally in your browser with no signup required.
Enter the object's submerged volume and the fluid density, and the buoyancy calculator computes the buoyant force using Archimedes' principle (F = ρ·V·g). Optionally add the object's mass to check whether it floats or sinks. All calculations run locally in your browser — no signup required.
Enter a submerged volume and fluid density to calculate the buoyant force.
Archimedes' Principle
Buoyant Force
F_b = ρ · V · g
ρ = fluid density, V = displaced volume, g = gravity
Displaced Mass
m = ρ · V
Mass of fluid displaced by the object
Float Condition
ρ_object < ρ_fluid
Object floats when less dense than fluid
Fraction Submerged
ρ_object / ρ_fluid
Portion of a floating object below the surface
All calculations run locally in your browser. No data is ever sent to a server.
Why Use Our Buoyancy Calculator?
Instant Buoyant Force Calculation
Enter the submerged volume and fluid density, and the buoyancy calculator returns the buoyant force instantly using Archimedes’ principle — no submit button needed. Results update in real time as you type.
Secure Buoyancy Calculator Online
Your values and calculations never leave your device. The buoyancy calculator runs 100% client-side in your browser — no server, no account, no data collection of any kind.
Buoyancy Calculator — No Installation
Use the buoyancy calculator directly in any modern browser with no downloads, no plugins, and no account required. Works on desktop and mobile — open the page and start calculating buoyant force immediately.
100% Free with Float/Sink Analysis
The buoyancy calculator is completely free with no signup, no usage limits, and no ads. Add the object mass and the calculator determines whether it floats or sinks, plus the fraction submerged at equilibrium.
Common Use Cases for Buoyancy Calculator
Physics Homework and Exam Prep
Students use the buoyancy calculator to solve Archimedes’ principle problems from textbooks and past papers. Entering volume and fluid density gives the buoyant force instantly, while the formula reference reinforces the underlying physics.
Boat and Ship Design
Naval architects use the buoyancy calculator to estimate the buoyant force on hull sections and verify displacement. Determining how much water a hull displaces is essential for confirming a vessel will float with its intended load.
Submarine and ROV Engineering
Engineers use the buoyancy calculator to balance ballast and achieve neutral buoyancy for submarines and remotely operated vehicles. The float/sink analysis helps tune the mass-to-volume ratio for stable underwater operation.
Scuba Diving and Buoyancy Control
Divers and instructors use the buoyancy calculator to understand how body volume and equipment affect buoyant force in fresh versus sea water. This helps plan weighting systems for safe, controlled descents and ascents.
Hot Air Balloon and Airship Estimates
Aeronautics enthusiasts use the buoyancy calculator with air as the fluid to estimate the lift generated by displaced air. The same Archimedes’ principle that floats boats in water lifts balloons in the atmosphere.
Material Density and Quality Testing
Lab technicians use the buoyancy calculator alongside displacement measurements to determine an object’s density and verify material composition. Comparing object density to fluid density reveals whether a sample will float or sink.
Understanding Buoyancy and Archimedes' Principle
What is Buoyancy?
Buoyancy is the upward force exerted by a fluid on any object immersed in it. According to Archimedes' principle, this buoyant force equals the weight of the fluid displaced by the object — expressed by the formula F = ρ · V · g, where ρ is the fluid density, V is the submerged volume, and g is gravitational acceleration. The buoyant force is what makes ships float, balloons rise, and submerged objects feel lighter. Our buoyancy calculator onlineapplies Archimedes' principle directly, computing the buoyant force from the volume and fluid density you enter, with support for multiple unit systems and gravity presets for different planets.
How Our Buoyancy Calculator Works
- Enter the Submerged Volume: Type the volume of the object that is submerged in the fluid and select a unit — cubic metres, litres, millilitres, cubic feet, or US gallons. The buoyancy calculator converts everything to SI base units internally for accuracy.
- Choose the Fluid and Gravity:Pick a fluid preset (fresh water, sea water, oil, mercury, and more) or enter a custom density. Select a gravity preset for Earth, Moon, Mars, or Jupiter, or enter a custom value. The buoyancy calculator instantly applies Archimedes' principle.
- Read the Buoyant Force and Float Analysis:The result shows the buoyant force in newtons and kilogram-force, plus the displaced fluid mass. Optionally enter the object's mass to determine whether it floats or sinks and what fraction sits below the surface. All calculations run locally in your browser.
What the Buoyancy Calculator Computes
- Buoyant Force: The upward force in newtons (N) and kilogram-force (kgf), calculated as F = ρ · V · g from the fluid density, submerged volume, and gravity.
- Displaced Fluid Mass:The mass of fluid pushed aside by the object, equal to ρ · V — the basis of Archimedes' principle.
- Float or Sink Verdict: When you provide the object mass, the calculator compares object density to fluid density and reports whether the object floats, sinks, or has neutral buoyancy.
- Fraction Submerged: For floating objects, the calculator shows the percentage of volume below the surface, equal to the ratio of object density to fluid density.
Important Notes About This Calculator
The buoyancy calculator assumes the fluid is incompressible and at rest, and that the object is fully or partially submerged with a known displaced volume. It uses a standard gravitational acceleration of 9.80665 m/s² for Earth, but you can select other planetary values or enter a custom one. For partially submerged floating objects, enter only the submerged portion as the volume, or enter the full volume plus the object mass to let the calculator determine the equilibrium fraction submerged. The calculator does not account for surface tension, fluid viscosity, or dynamic effects such as drag — it computes the static buoyant force from Archimedes' principle.
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Frequently Asked Questions About Buoyancy Calculator
A buoyancy calculator is a tool that computes the buoyant force on an object immersed in a fluid using Archimedes’ principle (F = ρ · V · g). You enter the submerged volume and fluid density, and the calculator returns the upward force in newtons and kilogram-force. Our buoyancy calculator online runs entirely in your browser with no signup, no server, and no data collection.
Archimedes’ principle states that the buoyant force on an object equals the weight of the fluid it displaces. Mathematically, F = ρ · V · g, where ρ is the fluid density, V is the displaced volume, and g is gravitational acceleration. The buoyancy calculator applies this principle directly to compute the buoyant force for any object and fluid combination.
Absolutely. The buoyancy calculator runs 100% client-side in your browser. Your values and calculations are never transmitted to any server, stored in a database, or tracked in any way. Everything stays completely private on your device.
Yes — the buoyancy calculator is 100% free with no signup, no account, and no usage limits. Solve as many buoyancy problems as you need, completely free forever. There are no ads, no premium tiers, and no data collection.
When you enter the object mass, the buoyancy calculator computes the object density (mass ÷ volume) and compares it to the fluid density. If the object is less dense than the fluid, it floats; if it is denser, it sinks; if the densities are equal, it has neutral buoyancy. The calculator also shows the net force — the difference between the buoyant force and the object’s weight.
The buoyant force is directly proportional to fluid density, so denser fluids exert more buoyant force on the same volume. Sea water (about 1025 kg/m³) is denser than fresh water (about 998 kg/m³), which is why objects float slightly higher in the ocean. The buoyancy calculator includes presets for common fluids and lets you enter any custom density.
For a floating object in equilibrium, the fraction submerged equals the ratio of the object density to the fluid density. For example, ice (917 kg/m³) floating in sea water (1025 kg/m³) sits with about 89% of its volume below the surface. The buoyancy calculator shows this percentage with a visual bar when an object floats.
Yes. Archimedes’ principle applies to any fluid, including gases. The buoyancy calculator includes an air preset (1.225 kg/m³), so you can estimate the lift on hot air balloons, weather balloons, and airships. The buoyant force from displaced air is what allows lighter-than-air craft to rise.
Yes. The buoyant force depends on gravitational acceleration, so the calculator includes presets for Earth, Moon, Mars, and Jupiter, plus a custom option. Lower gravity reduces both the buoyant force and the object’s weight proportionally, so whether an object floats or sinks does not change with gravity — only the magnitude of the forces does.