Basic Mass Calculator
What is Mass?
Mass is typically defined as the amount of matter within an object. It is most commonly measured as inertial mass, involving an object's resistance to acceleration given some net force. Matter, however, is somewhat loosely defined in science, and cannot be precisely measured. In classical physics, matter is any substance that has mass and volume.
The amount of mass that an object has is often correlated with its size, but objects with larger volumes do not always have more mass. An inflated balloon, for example, would have significantly less mass than a golf ball made of silver. While many different units are used to describe mass throughout the world, the standard unit of mass under the International System of Units (SI) is the kilogram (kg).
There exist other common definitions of mass including active gravitational mass and passive gravitational mass. Active gravitational mass is the measure of how much gravitational force an object exerts, while passive gravitational mass is the measure of the gravitational force exerted on an object within a known gravitational field. While these are conceptually distinct, there have not been conclusive, unambiguous experiments that have demonstrated significant differences between gravitational and inertial mass.
Key Characteristics of Mass:
- Scalar quantity - has magnitude only, no direction
- Constant property - doesn't change with gravity or location
- SI Unit: Kilogram (kg) - international standard
- Determines inertia - resistance to acceleration (F=ma)
- Three mass types: Inertial, Active Gravitational, Passive Gravitational
Volume vs Mass Examples:
| Object | Volume | Mass | Density |
|---|---|---|---|
| Silver Golf Ball | Small | ~45g | High (10.5 g/cm³) |
| Inflated Balloon | Large | ~2g | Low (0.001 g/cm³) |
| Apple | Medium | 180g | Medium |
| Feather | Medium | 1g | Very Low |
Proves volume ≠ mass. Use our calculator for accurate mass conversions.
Mass vs. Weight: Key Differences
Mass and weight are often confused, but they're fundamentally different. Mass = matter quantity. Weight = gravitational force on that mass.
| Mass (Inertial) | Weight | |
|---|---|---|
| Definition | Amount of matter | Gravitational force |
| Formula | Intrinsic property | W = m × g |
| Units | kg, lbs, gram | newtons (N), lbf |
| Constant? | Yes - everywhere | No - varies by gravity |
| 65kg Person | 65 kg (always) | 638 N (Earth) 106 N (Moon) |
Real-world example: Astronauts have same mass on Moon as Earth, but 1/6th weight due to weaker gravity. Our calculator measures mass only.
How to Use Our Mass Calculator
- Select input unit (kg, lb, g, tons, etc.)
- Enter value in the field
- Choose output unit from dropdown
- Get instant conversion across all units
Supports metric ↔ imperial conversions with high precision for scientific and commercial use.
Frequently Asked Questions
What are the three types of mass?
Inertial mass (resistance to acceleration), active gravitational mass (gravitational force exerted), and passive gravitational mass (gravitational force experienced). Experiments show they're equivalent.
Why doesn't a larger object always have more mass?
Mass depends on density × volume. An inflated balloon has large volume but very low density, while metals have high density in small volumes.
What is the SI unit of mass?
The kilogram (kg) is the SI standard unit of mass worldwide.
How many pounds in a kilogram?
1 kg = 2.20462 pounds. Enter value in our calculator for instant conversion.
Is this calculator precise for science?
Yes, uses high-precision algorithms suitable for scientific, engineering, and gravitational mass calculations.