Mechanics
Weight
Weight is the gravitational force on an object.
Variables
WN
Weight
Gravitational force
In SI units: kg·m/s²
mkg
Mass
Mass of object
Allowed values: 0 or more
gm/s²
Gravitational acceleration
≈ 9.8 m/s²
Allowed values: greater than 0
Derivation
Special case of F = ma where a = g.
Your notes
0/5000
Constants in this formula
Check value
Round inputs run through this page's calculator, with each constant at its tabulated value. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.
- m = 2 kg (Mass)
- g = 9.806 65 m/s² (Gravitational acceleration)
Result: W = 19.6133 N
Other mechanics formulas with the same quantities
- Terminal Velocity (Dynamics) shares Mass, Gravitational acceleration
- Free Fall (Kinematics) shares Gravitational acceleration
- Projectile Range (Kinematics) shares Gravitational acceleration
- Projectile Maximum Height (Kinematics) shares Gravitational acceleration
- Projectile Time of Flight (Kinematics) shares Gravitational acceleration
- Gravitational Potential Energy (Work & Energy) shares Gravitational acceleration
Where this formula is listed
- Mechanics formulas, under Dynamics, alongside Friction Force, Hooke's Law, Drag Force, Center of Mass (Two Objects) and Pressure.
- In the mechanics list it comes after Newton's Second Law and before Friction Force.
- Mechanics formula sheet, one of 58 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Weight formula?
Weight is written W = mg. Weight is the gravitational force on an object. It belongs to Mechanics, under Dynamics.
What are the units in W = mg?
In SI units, W is weight, measured in kg·m/s²; m is mass, measured in kg; g is gravitational acceleration, measured in m/s².
How is the Weight formula derived?
Special case of F = ma where a = g. The result is W = mg.