Mass Calculator

Q: How do I find the mass of an irregularly shaped object?

First, find the volume of the object. A common method is water displacement . Fill a container with water and note the level. Submerge the object and note the new level. The difference is the object's volume. Then enter that volume and the material's density into the calculator to get the mass.

Q: Can I use this calculator to find the density of an unknown material?

Yes. Switch the mode to Density at the top. Enter the mass and volume of your object. The calculator will divide mass by volume and give you the density. You can then compare that density to known materials to help identify what the object is made of.

Q: What density value should I use for my material?

Use the Material Preset dropdown for common materials like water, steel, copper, or gold. If your material is not listed, look up its density on the manufacturer's datasheet or a reference table. Choose "Custom" from the dropdown and type the value in yourself. Make sure the units match what your source lists.

Q: How do I calculate the volume if I know mass and density?

Click the Volume mode at the top. Enter the mass and density of your object. The calculator divides mass by density to find the volume. The formula is V = m ÷ ρ . Your result will appear in the unit you choose from the output dropdown.

Mass Calculator

Updated Jul 10, 2026 By Jehan Wadia

Introduction

Mass is the amount of matter in an object. To find the mass of something, you need two pieces of information: its density (how tightly packed the matter is) and its volume (how much space it takes up). The formula is simple: Mass = Density × Volume.

This mass calculator lets you solve for mass, density, or volume using that one formula. Pick a common material like water, steel, or gold, or type in your own density value. Choose from dozens of units — kilograms, pounds, grams, ounces, liters, cubic feet, and many more. The calculator converts everything for you and shows your answer in multiple units at once.

Each calculation comes with a step-by-step solution so you can see exactly how the math works. Whether you are doing a homework problem, planning a project, or figuring out how heavy a material will be, this tool gives you a fast and accurate answer.

How to Use Our Mass Calculator

Enter any two of the three values — mass, density, and volume — and this calculator will solve for the missing one. You can also pick a material preset and change units to get your answer in the format you need.

Choose what to solve for. Click "Mass," "Density," or "Volume" at the top. This tells the calculator which value to find using the other two.

Pick a material or enter a custom density. Use the Material Preset dropdown to select a common material like water, steel, or gold. The density field will fill in for you. If your material is not listed, choose "Custom" and type in your own density value.

Set your density units. Use the two dropdown menus next to the density field to pick the mass unit and volume unit for your density. For example, kg/m³ or g/cm³. Press the swap button to flip the numerator and denominator units.

Enter the volume. Type the volume of your object and pick a unit from the dropdown, such as liters, cubic meters, or gallons.

Enter the mass. If you are solving for density or volume, type the mass of your object and pick a unit like kilograms, grams, or pounds.

Choose your output unit. Use the "Show result in" dropdown to pick the unit you want your answer displayed in.

Turn on scientific notation. If you work with very large or very small numbers, flip the scientific notation toggle to show results in exponential form. You can also use our scientific notation calculator for standalone conversions.

Get your result. Press the "Calculate" button. Your answer appears in the Result box. Below it, you will find the same result converted into many other units, a visual scale, and a full step-by-step solution showing how the math was done.

How to Calculate Mass from Density and Volume

Mass is the amount of matter in an object. It tells you how much "stuff" something is made of. Mass is not the same as weight. Weight changes depending on gravitational force, but mass stays the same everywhere.

To find the mass of an object, you need two things: its density and its volume. Density is how tightly packed the matter is inside an object. Volume is how much space the object takes up. The formula is simple:

Mass = Density × Volume

For example, copper has a density of 8,900 kg/m³. That means every cubic meter of copper holds 8,900 kilograms of matter. If you have 0.5 cubic meters of copper, the mass is 8,900 × 0.5 = 4,450 kg.

What Is Density?

Density measures how heavy a material is for its size. A block of gold is much heavier than a block of wood the same size because gold has a higher density. Every material has its own density. Water has a density of 1,000 kg/m³. Steel is about 7,850 kg/m³. Air at sea level is only 1.225 kg/m³. For a deeper look at how density works, try our density calculator.

Objects with a density lower than water will float. Objects with a density higher than water will sink. This is why wood floats and rocks sink. This principle is at the heart of buoyancy, which determines whether an object rises or sinks in a fluid.

Rearranging the Formula

The same formula lets you solve for any of the three variables:

Mass: m = ρ × V — multiply density by volume.
Density: ρ = m ÷ V — divide mass by volume.
Volume: V = m ÷ ρ — divide mass by density.

This calculator handles all three. Pick the variable you want to find, enter the other two values, and choose your units. It works with metric units like kilograms and cubic meters, imperial units like pounds and cubic feet, and many more.

Common Uses

Engineers use mass calculations to figure out how heavy a metal part will be before they build it. For specific materials, dedicated tools like a steel weight calculator or an aluminum weight calculator can help estimate weight for standard shapes. Scientists use them to identify unknown materials by measuring mass and volume, then calculating density. Shipping companies need mass to estimate freight density and costs. Students use the formula in science class to solve homework problems.

Knowing the mass of an object helps you plan for weight limits, structural support, material costs, and transportation. Mass also plays a key role in related physics concepts like force, momentum, and kinetic energy. Whether you are working with a tiny piece of aluminum or a large block of concrete, the math is the same — just plug in the density and volume, and multiply.

Formulas used

Mass from Density and Volume

m = \rho \times V

Density from Mass and Volume

\rho = \frac{m}{V}

Volume from Mass and Density

V = \frac{m}{\rho}

Frequently asked questions

What is the difference between mass and weight?

Mass is the amount of matter in an object. It stays the same no matter where you are. Weight is the force of gravity pulling on that mass. On the Moon, you weigh less because gravity is weaker, but your mass does not change. This calculator finds mass, not weight.

What units can I use in this calculator?

You can use a wide range of units. For mass, you can pick kilograms, grams, milligrams, pounds, ounces, stones, tons, carats, grains, slugs, and all SI prefix grams. For volume, you can pick liters, milliliters, cubic meters, cubic centimeters, cubic feet, cubic inches, gallons (US and UK), cups, pints, quarts, barrels, and more. The calculator converts between all of them automatically.

How do I find the mass of an irregularly shaped object?

First, find the volume of the object. A common method is water displacement. Fill a container with water and note the level. Submerge the object and note the new level. The difference is the object's volume. Then enter that volume and the material's density into the calculator to get the mass.

What does the swap button next to the density units do?

The swap button flips the mass unit and volume unit in the density field. For example, if your density is set to kg/m³, pressing swap will try to switch it to m³/kg. If that exact swap is not possible, it defaults to kg/L. This makes it easy to rearrange your density units quickly.

Why does my result show a very large or very small number?

This happens when there is a big difference between your input units and output units. For example, converting a large volume in cubic meters to mass in milligrams gives a huge number. Turn on the scientific notation toggle to make these numbers easier to read.

How accurate is this calculator?

The calculator uses 7 significant figures of precision. The material presets use standard reference densities at room temperature and normal pressure. For most schoolwork, engineering estimates, and everyday projects, this level of accuracy is more than enough.

Can I use this calculator to find the density of an unknown material?

Yes. Switch the mode to Density at the top. Enter the mass and volume of your object. The calculator will divide mass by volume and give you the density. You can then compare that density to known materials to help identify what the object is made of.

What density value should I use for my material?

Use the Material Preset dropdown for common materials like water, steel, copper, or gold. If your material is not listed, look up its density on the manufacturer's datasheet or a reference table. Choose "Custom" from the dropdown and type the value in yourself. Make sure the units match what your source lists.

Does temperature affect the density of a material?

Yes. Most materials expand when heated and contract when cooled. This changes their volume, which changes their density. For example, water at 4°C has a density of about 1,000 kg/m³, but at 80°C it drops to about 972 kg/m³. The preset values in this calculator use standard room temperature conditions.

How do I calculate the volume if I know mass and density?

Click the Volume mode at the top. Enter the mass and density of your object. The calculator divides mass by density to find the volume. The formula is V = m ÷ ρ. Your result will appear in the unit you choose from the output dropdown.

What is the density of water?

Pure water at 4°C has a density of 1,000 kg/m³, which equals 1 g/cm³ or 1 g/mL. This is a handy reference point because 1 liter of water has a mass of exactly 1 kilogram. Seawater is slightly denser at about 1,025 kg/m³ because of the dissolved salt.

Can I copy the result to use somewhere else?

Yes. Click the copy button (the small clipboard icon) next to the result. The value and unit will be copied to your clipboard. A "Copied!" message will briefly appear to confirm it worked.

Why does the calculator show results in other units below the main answer?

The multi-unit table saves you time. Instead of running separate conversions, you can see your result in kilograms, grams, pounds, ounces, tons, and more all at once. This is helpful when you need the same answer in different unit systems.

What does the visual conversion scale show?

The scale is a simple diagram that shows how your result changes when you halve or double one of the inputs. It helps you see the linear relationship between the variables. For example, if you double the volume while keeping density the same, the mass also doubles.

Is mass the same in metric and imperial systems?

The amount of matter does not change, but the number changes depending on the unit. One kilogram equals about 2.205 pounds. This calculator converts between metric and imperial units for you, so you can enter values in one system and see the result in another.