Skip to content
OneKitly
Sign up · Sign in

Force calculator (F = ma)

Compute force from mass and acceleration using Newton's second law.

Related tools

All Physics tools →
Centripetal force calculatorCompute the centripetal force on an object moving in a circle (F = mv²/r).Gravitational force calculatorCompute the gravitational attraction between two masses (Newton's law).Friction force calculatorCompute the friction force from the coefficient of friction and the normal force (F = μN).Hydraulic Cylinder Force CalculatorPush and pull force of a hydraulic cylinder from F = P × A, with the rod annulus handled properly, the area ratio φ and an ISO bore table.Acceleration calculatorCompute acceleration from the change in velocity over time.Displacement calculatorCompute displacement from initial velocity, acceleration and time (s = ut + ½at²).Hooke's law calculatorCompute the force of a spring from its stiffness and displacement (F = kx).Impulse calculatorCompute impulse from a force applied over a time (J = F·t).

The Force calculator (F = ma) turns Mass (kg), Acceleration (m/s²) into Force (N), instantly and for free. For instance, with Mass (kg) = 10 and Acceleration (m/s²) = 9.8 it returns Force (N) = 98.

How to use it

  1. Enter your values: Mass (kg), Acceleration (m/s²).
  2. Read the result instantly: Force (N).

Frequently asked questions

How does the Force calculator (F = ma) work?

It takes Mass (kg) and Acceleration (m/s²) and derives Force (N) from them. The calculation is live as you type, so the result updates on every change.

Which values does the calculator ask for?

2 values: Mass (kg) and Acceleration (m/s²). Nothing else is required — no account, no file upload.

What does a typical calculation look like?

With Mass (kg) = 10 and Acceleration (m/s²) = 9.8, the calculator returns Force (N) = 98. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

How much does the result change with different inputs?

It moves a lot. Using Mass (kg) = 11 and Acceleration (m/s²) = 19.6 instead, Force (N) goes from 98 to 215.6 — which is why it is worth testing a few scenarios rather than trusting a single figure.

What does it give for smaller values?

Scaled down to Mass (kg) = 9 and Acceleration (m/s²) = 4.9, Force (N) comes out at 44.1. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Checking a homework answer, sizing something before building it, and getting an order of magnitude before committing to a design — a torque on a bolt, the force a spring returns, the frequency a circuit resonates at, how long light takes to arrive.

What is the most common mistake?

Feeding in a value in the wrong unit. Physics formulas assume SI throughout, so grams instead of kilograms or centimetres instead of metres shifts the answer by powers of ten without any warning.

What is the difference between the Force calculator (F = ma) and the Centripetal force calculator?

This one returns Force (N); the Centripetal force calculator returns Centripetal force (N). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Gravitational force calculator is the closest one after this: Compute the gravitational attraction between two masses (Newton's law).

What else is worth having open alongside it?

Friction force calculator and Hydraulic Cylinder Force Calculator — they come up in the same task often enough to be worth a second tab.

Further reading

All guides →
ExplainerHooke's Law Explained: F = kx, Real Spring Constants, and Where It Stops HoldingHooke's law says force is proportional to stretch — but only below the elastic limit. Here is F = kx with worked numbers, what a 200 N/m spring actually feels like, and how springs combine.GuideThe Four Kinematics Equations: Which One to Use, and What Each One Leaves OutFive variables, four equations, and each equation is missing exactly one of them. Choose by looking at the variable the question never mentions.ExplainerHow the Doppler Effect Works: The Formula, the Sign Convention, and Why Moving the Source Is Not the Same as Moving the ListenerFor sound, f' = f(v + v_o)/(v − v_s) — and getting the signs backwards is the classic error. Here is the convention spelled out, a 440 Hz source computed at four speeds, and why light needs a different equation entirely.ExplainerWhat Is the Reynolds Number? The Formula, the Units That Cancel, and Why 2 300 Is Only for PipesRe = ρvL/μ compares inertia with viscosity, and the units really do cancel. See the number worked out for honey, a household pipe, an artery, a swimmer and a wing — and why the 2 300 threshold belongs to pipe flow alone.ExplainerHow Buoyancy Works: Archimedes' Principle, and Why Ice Floats With 10.5 % Above WaterThe upward force equals the weight of the fluid pushed aside. That one sentence decides whether something floats, and if it floats, exactly how much of it stays under.ExplainerProjectile Motion Explained: Range, Height, Flight Time — and Why 45° Is Not Always BestThree formulas cover the whole of projectile motion on level ground. The catch is level ground: the moment launch and landing heights differ, the 45° result stops being true.
Force calculator (F = ma) — OneKitly