Weight Calculator - Mass vs. Weight & Solar System Planets
Free online weight and mass calculator. Convert across international weight and mass units (lbs, kg, stones, ounces, metric tonnes, US tons, Newtons) and discover how much you would weigh on other planets, the Moon, and the Sun based on celestial surface gravity.
Weight vs. Mass & Celestial Planetary Calculator
Convert across weight & mass units and calculate your exact weight on the Moon, Mars, Jupiter, and across the solar system.
Weight vs. Mass & Celestial Gravity Guide: Gravitational Physics & Planetary Weights
While mass represents the invariant quantity of matter in an object, weight is the gravitational force exerted upon that mass. This guide explores gravitational acceleration across the solar system, unit conversions, and celestial weight variations.
The Law of Universal Gravitation & Weight
Weight Formula: W = m · g (Newtons or pounds-force)
Where m is mass and g is local gravitational acceleration (Earth: 9.807 m/s², Moon: 1.622 m/s², Mars: 3.721 m/s², Jupiter: 24.79 m/s²).
Step-by-Step Instructions
Enter Body or Object Mass
Input mass or weight in Kilograms (`kg`), Pounds (`lbs`), Stone (`st`), Grams (`g`), or Ounces (`oz`).
Select Gravitational Environment (Planetary Body)
Choose Earth standard gravity (`1.0g` = 9.80665 m/s²), Moon, Mars, Jupiter, Venus, or zero-g space orbit.
Compute Gravitational Force & Mass Conversions
Review equivalent force in Newtons (`N`), Pounds-force (`lbf`), and localized planetary scale weights.
Inspect Healthy Body Weight Metrics (For Humans)
Toggle Human Mode to compute Ideal Body Weight (Devine, Robinson, Miller formulas) and Body Mass Index (BMI).
Key Features & Capabilities
- Universal mass and weight unit converter: Pounds (`lbs`), Kilograms (`kg`), Stone & Pounds (`st lb`), Ounces (`oz`), Grams (`g`), and Newtons (`N`)
- Planetary weight simulator: calculate what an object or person weighs across all solar system planets, the Moon, and Pluto
- Medical Ideal Body Weight (IBW) calculator implementing standard clinical formulas (Devine, Robinson, Miller, and Hamwi equations)
- BMI and Healthy Weight Range calculator calibrated for adult height and gender
- High precision fractional arithmetic preventing rounding discrepancies
- Instant client-side calculation with zero server latency
Frequently Asked Questions
How do you convert between Pounds (lbs) and Kilograms (kg)?
The exact international conversion factor is: `1 Pound = 0.45359237 Kilograms` (or `1 kg ≈ 2.20462 lbs`). To convert kg to lbs, multiply by 2.20462. To convert lbs to kg, divide by 2.20462.
How much would a 150 lb person weigh on the Moon and Mars?
Surface gravity on the Moon is 16.6% of Earth's (`1.62 m/s²`), so a 150 lb person weighs only `150 * 0.166 = 24.9 lbs` on the Moon. On Mars (gravity is 37.9% of Earth's / `3.72 m/s²`), the person weighs `150 * 0.379 = 56.8 lbs`.
How does the British Stone (st) weight measurement work?
One Stone equals exactly 14 Pounds (`1 st = 14 lbs ≈ 6.35029 kg`). In the UK and Ireland, body weight is conventionally expressed in stone and pounds (e.g., 150 lbs is expressed as `10 stone 10 lbs` / `10st 10lb`).
What is the Devine Formula for Ideal Body Weight (IBW)?
The Devine formula is the medical standard used for drug dosing: For Men: `IBW (kg) = 50.0 + 2.3 * (Height in inches - 60)`. For Women: `IBW (kg) = 45.5 + 2.3 * (Height in inches - 60)`.
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