💪Force Calculator (F = ma)
Solve for force, mass, or acceleration using Newton's second law, with unit conversion and an optional net-force mode.
Free Force Calculator
Working through a Newton's Second Law problem? Our free Force Calculator solves F = ma instantly — enter any two of force, mass, or acceleration, and get the third immediately, with the formula and substitution shown clearly.
Unit conversions are built in, so you can mix newtons and pounds-force, kilograms and pounds, without converting by hand first. For problems with multiple forces acting on an object, the net-force mode lets you add up individual forces along one axis before solving for the resulting acceleration — exactly how real mechanics problems are set up.
Whether you're checking Newton's laws homework or working through an engineering statics problem, this tool gives you the answer with the reasoning shown. No sign-up, no downloads, no limits. See the About page or the FAQ for more.
About the Force Calculator
Features
Solve for F, m, or a
Enter any two known quantities to solve for the third.
Unit conversion
Mix newtons/pounds-force, kilograms/pounds, and m/s²/ft/s²/g-force freely.
Net-force summation mode
Add multiple signed forces along one axis before solving for acceleration.
Step-by-step working
Every result shows the formula and substitution with your actual values.
Frequently Asked Questions
How does the force calculator work?
Enter any two of force, mass, or acceleration; it solves for the third using F = ma and shows the working.
Is it free?
Completely free, no sign-up, downloads, or limits.
What is Newton's Second Law?
It states that force equals mass times acceleration (F = ma), describing how an object accelerates under a net force.
Can it handle multiple forces?
Yes, the net-force mode lets you add several forces along one axis to find the total before solving.
Does it convert units?
Yes, force, mass, and acceleration can each be entered in common units (N, lbf, kg, lb, m/s², ft/s²) with automatic conversion.
Does it show the steps?
Yes, the formula and substitution with your actual values are shown for every calculation.
What if I enter a negative or zero mass?
Mass must be positive; the calculator flags invalid mass values rather than returning a meaningless result.
Can this help with engineering problems?
Yes, it's useful for basic statics and dynamics calculations involving Newton's second law.
Is my data stored?
No; everything runs in your browser and isn't stored or sent anywhere.
Does it work on mobile?
Yes, fully responsive on all screen sizes.