Mass vs Weight
Mass is intrinsic and doesn’t change with location. It’s measured in kilograms, grams, pounds, ounces, stones, and tons. Weight is a force: the pull of gravity on that mass. On Earth, weight can be estimated by multiplying mass by standard gravity 9.80665 m/s².
Core formulas
Mass (kg) → Pounds (lb): lb = kg × 2.20462262
Pounds (lb) → kg: kg = lb ÷ 2.20462262
Weight (N) → kgf: kgf = N ÷ 9.80665
kgf → N: N = kgf × 9.80665
Common use cases
- Lab / chemistry: convert mg ↔ g ↔ kg quickly.
- Shipping / logistics: convert between kg and lb/st/short ton.
- Engineering / structural: work in N or kN, but report in kgf to non-technical stakeholders.
FAQ
1. Can I enter a very small mass like micrograms?
Yes, µg is supported. The converter internally uses kilograms as a base, so precision is preserved.
2. Why do you show both US short ton and UK long ton?
Because 1 US short ton = 2000 lb (≈ 907.18474 kg), while 1 UK long ton = 2240 lb (≈ 1016.0469 kg). Mixing them causes invoicing errors.
3. How to get weight on the Moon?
Weight = mass × Moon gravity (1.62 m/s²). Our main weight tab assumes Earth gravity; for other planets, multiply manually by the local gravitational acceleration.
Formula (LaTeX) + variables + units
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Mass (kg) → Pounds (lb): lb = kg × 2.20462262 Pounds (lb) → kg: kg = lb ÷ 2.20462262 Weight (N) → kgf: kgf = N ÷ 9.80665 kgf → N: N = kgf × 9.80665
- No variables provided in audit spec.
- NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures - NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units
Last code update: 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.