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Hooke's law calculator

Compute the force of a spring from its stiffness and displacement (F = kx).

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Enter Spring constant (N/m), Displacement (m) and the Hooke's law calculator works out Spring force (N) straight away. For instance, with Spring constant (N/m) = 200 and Displacement (m) = 0.1 it returns Spring force (N) = 20.

How to use it

  1. Enter your values: Spring constant (N/m), Displacement (m).
  2. Read the result instantly: Spring force (N).

Frequently asked questions

What does the Hooke's law calculator actually compute?

It takes Spring constant (N/m) and Displacement (m) and derives Spring force (N) from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

2 values: Spring constant (N/m) and Displacement (m). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Spring constant (N/m) = 200 and Displacement (m) = 0.1, the calculator returns Spring force (N) = 20. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Spring constant (N/m) = 400 and Displacement (m) = 0.11 instead, Spring force (N) goes from 20 to 44 — 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 Spring constant (N/m) = 100 and Displacement (m) = 0.09, Spring force (N) comes out at 9. 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 Hooke's law calculator and the Spring constant calculator (Hooke's law)?

This one returns Spring force (N); the Spring constant calculator (Hooke's law) returns Result and Effective k (N/m). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Coulomb's Law Calculator is the closest one after this: Solve F = kq₁q₂/εᵣr² for the force, either charge or the distance, in any of 18 dielectric media, with charges in C, µC, nC or elementary charges, plus the potential energy and the field at q₂.

What else is worth having open alongside it?

Kepler's Third Law Calculator and Snell's Law 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.ExplainerThe Ideal Gas Law Explained: PV = nRT, R in Every Unit, and Where It BreaksPV = nRT holds when the gas is dilute and far from condensing. The value of R depends entirely on the units you feed it, and the temperature is never in degrees Celsius.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.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.