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Weight from mass calculator

Compute the weight (force of gravity) of an object from its mass (W = mg).

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Enter Mass (kg), Gravity (m/s²) and the Weight from mass calculator works out Weight (N) straight away. For instance, with Mass (kg) = 70 and Gravity (m/s²) = 9.81 it returns Weight (N) = 686.7.

How to use it

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

Frequently asked questions

What does the Weight from mass calculator actually compute?

It takes Mass (kg) and Gravity (m/s²) and derives Weight (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: Mass (kg) and Gravity (m/s²). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Mass (kg) = 70 and Gravity (m/s²) = 9.81, the calculator returns Weight (N) = 686.7. 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 Mass (kg) = 77 and Gravity (m/s²) = 19.62 instead, Weight (N) goes from 686.7 to 1,511 — 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) = 63 and Gravity (m/s²) = 4.91, Weight (N) comes out at 309.33. 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 Weight from mass calculator and the Weight on other planets calculator?

This one returns Weight (N); the Weight on other planets calculator returns Weight there (kg). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

E = mc² Calculator (Mass–Energy) is the closest one after this: Convert mass into energy and back with a realistic efficiency — 100 % for antimatter, 0.7 % for fusion, 0.09 % for fission — and read the result in joules, kWh, kcal and tonnes of TNT.

What else is worth having open alongside it?

Potential energy calculator and Molar Mass Calculator — they come up in the same task often enough to be worth a second tab.

Further reading

All guides →
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.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.How-toHow to Calculate Molar Mass, Including Parentheses and HydratesMultiply each atomic weight by its subscript and add. The only three places the arithmetic goes wrong are a subscript after a closing bracket, the hydrate dot, and a capital letter typed as a lowercase one.ExplainerWhat Would You Weigh on Other Planets?Weight depends on gravity, but mass does not — here is why you would weigh differently on the Moon, Mars and Jupiter, and how to work it out.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.