Length Converter

Length conversion translates a value between the metric system (mm, cm, m, km), the imperial/US system (inch, foot, yard, mile), the Korean traditional unit (ja/尺), and the nautical mile used in navigation. This tool converts every unit through a common meter (m) base so any pair can be computed instantly.

Enter a value, choose the from and to units, and the result updates automatically. Use Swap units to flip the two selections.

Result = value × (from-unit meters) ÷ (to-unit meters)

Common conversions: 1 inch = 2.54cm, 1 foot = 30.48cm, 1 yard = 0.9144m, 1 mile ≈ 1.609km, 1 ja ≈ 30.3cm.

Pyeong, still common in Korean real estate, is defined as exactly 400/121㎡, or 3.305785㎡ (1 pyeong is the area of a 6-ja square). A 2007 revision to the Measurement Act made ㎡ mandatory in official documents, but real-estate listings and interior-design quotes still often show pyeong alongside it by convention. For example, an apartment with 84㎡ of exclusive area is 84 ÷ 3.305785 ≈ 25.4 pyeong — which is also why the popular "84㎡ unit" is commonly called a "34-pyeong unit" (that figure is based on supply area, so it differs somewhat from the exclusive-area conversion).

The distance unit "ri (里)," as in the old saying "your feet ache before you've gone 10 ri," is still used colloquially, but its exact definition has varied slightly by era and region, so it's a customary unit qualitatively understood as roughly 10 ri ≈ 4km rather than a fixed figure. The inch (2.54cm), on the other hand, is a prominent metric-system holdout in Korea, still used at full international spec for monitor/TV screen diagonals (e.g. a 24-inch monitor has a diagonal of about 60.96cm), car and bicycle wheel diameters (e.g. a 17-inch wheel is about 43.18cm across), laptop sizing, and more. The reason the display and tire industries keep using inches is that the original specs were set in the US, and the global manufacturing ecosystem has stayed locked to those dimensions ever since.