Mass Calculator Online Free Tool
Mass Calculator
Mass Formula
m = mass
ρ (rho) = density
V = volume
Input Values
Calculated Mass
Result: 8900 kg/m³ × 1 m³ = 0 kg
Values Summary
Mass Comparison (1 m³ volume)
Mass and weight are related but distinct concepts that are often used interchangeably in everyday language. This calculator converts between mass units (kg, g, mg, lb, oz, ton), computes mass from density and volume (m = ρV), or finds mass from weight and gravity (m = F/g). Understanding the difference between mass and weight matters in science, engineering, nutrition labeling, shipping, and any situation where you need to work across metric and imperial measurement systems.
Mass Unit Conversions
Mass can be expressed in metric units (grams, kilograms, metric tons) or imperial/US units (ounces, pounds, short tons). The metric system is base-10, making conversions straightforward by moving the decimal point. Converting between metric and imperial requires the fixed factor of 1 pound = 453.592 grams.
| Unit | Kilograms | Grams | Pounds |
|---|---|---|---|
| 1 kilogram (kg) | 1 | 1,000 | 2.205 |
| 1 gram (g) | 0.001 | 1 | 0.00220 |
| 1 milligram (mg) | 0.000001 | 0.001 | 0.0000022 |
| 1 pound (lb) | 0.4536 | 453.6 | 1 |
| 1 ounce (oz) | 0.02835 | 28.35 | 0.0625 |
| 1 metric ton | 1,000 | 1,000,000 | 2,205 |
| 1 short ton (US) | 907.2 | 907,200 | 2,000 |
Mass vs Weight
Mass is the amount of matter in an object and stays constant regardless of location. Weight is the gravitational force pulling on that mass and changes with gravitational field strength. An astronaut with a mass of 80 kg has the same mass everywhere in the universe, but weighs 784 N on Earth, 130 N on the Moon, and essentially 0 on the International Space Station (in free fall). In daily life this distinction rarely matters because we always measure on Earth where gravity is constant, but in science and engineering the difference is critical.
Weight (N) = Mass (kg) × g g = 9.81 m/s² (Earth surface) g = 1.62 m/s² (Moon surface) g = 3.72 m/s² (Mars surface) g = 24.8 m/s² (Jupiter surface)
Example: 70 kg person. Earth weight = 70 × 9.81 = 686.7 N. Moon weight = 70 × 1.62 = 113.4 N.
Mass from Density and Volume
When you know the density of a material and need to find how much a given volume weighs, use the relationship between mass, density, and volume. This is essential for estimating material costs in construction, calculating shipping weight for bulk goods, and lab work where you measure volume but need mass for a reaction.
Mass = Density × Volume m = ρ × V Examples: 1 liter of water (ρ = 1 kg/L): m = 1 × 1 = 1 kg 1 cubic foot of concrete (ρ ≈ 2,307 kg/m³ = 144 lb/ft³): m ≈ 144 lb 1 gallon of gasoline (ρ ≈ 0.74 kg/L, 3.785 L/gal): m ≈ 2.8 kg (6.1 lb)
Molar Mass in Chemistry
In chemistry, mass calculations extend to the atomic scale. The molar mass of an element or compound (in grams per mole) numerically equals its atomic or molecular weight. One mole of water (H₂O, molecular weight 18.015) weighs 18.015 grams. This lets chemists convert between measurable mass on a lab scale and the number of molecules participating in a reaction.
Frequently Asked Questions
What is the difference between mass and weight?⌄
Mass is intrinsic to the object: it measures how much matter the object contains and never changes with location. Weight is the gravitational force acting on that mass and depends on the local gravitational field. In everyday speech "weight" is used for both, but in physics they are distinct quantities with different units. Mass is measured in kilograms; weight is measured in Newtons. A scale in a grocery store measures weight but is calibrated to display mass in kg or lb because Earth's gravity is essentially constant at the surface.
What is atomic mass?⌄
Atomic mass (also called atomic weight) is the average mass of one atom of an element, expressed in unified atomic mass units (u or Da, Daltons). It reflects the weighted average of all naturally occurring isotopes of that element. For example, carbon has two main isotopes: carbon-12 (about 99% of natural carbon) and carbon-13 (about 1%), giving carbon an atomic mass of 12.011 u rather than exactly 12. Molecular weight is the sum of atomic masses of all atoms in one molecule of a compound.
How do scales measure mass?⌄
Most bathroom and kitchen scales measure weight (the force you exert on the scale due to gravity) using spring compression or strain gauge sensors. They are then calibrated assuming standard Earth gravity (9.81 m/s²) to display mass in kilograms or pounds. This calibration works well for everyday use because gravity at the Earth's surface varies by less than 0.5% between the equator and poles. A precision analytical balance used in chemistry labs compares the unknown mass against known reference masses using a beam or electromagnetic force, making it independent of local gravity variations.
What is the lightest and heaviest naturally occurring element?⌄
Hydrogen (H, atomic mass 1.008 u) is the lightest element and the most abundant in the universe. Uranium (U, atomic mass 238.03 u) is the heaviest element that occurs in nature in significant quantities, though trace amounts of plutonium also occur naturally in uranium ores via neutron capture reactions. Artificially created superheavy elements like Oganesson (Og, element 118, atomic mass ~294 u) are even heavier, but they exist for only fractions of a second and are synthesized in particle accelerators, not found in nature.
How do I convert pounds to kilograms?⌄
Multiply pounds by 0.453592 to get kilograms. Divide kilograms by 0.453592 (or multiply by 2.20462) to get pounds. Quick mental approximation: divide pounds by 2.2 to get approximate kilograms, or multiply kilograms by 2.2 to get approximate pounds. Example: 150 lb ÷ 2.2 ≈ 68.2 kg. For body weight, this approximation is close enough for practical purposes.