📏 Ken Length Converter (間 to m)

The Ken Length Converter converts between ken (間) and modern length units. The ken is a traditional Japanese length unit equal to 6 shaku, or approximately 1.818 meters (5.96 feet).

In Japanese architecture, the ken is much more than a measurement - it is the fundamental structural grid module. The "kiwari" (木割, timber proportioning) system uses ken as the base unit for everything from pillar spacing to roof beam length.

There are historically two types of shaku: kane-jaku (metal ruler, 30.30 cm, used for architecture and general measurement) and kujira-jaku (whale ruler, 37.88 cm, used only for traditional carpentry/tailoring). The ken uses kane-jaku.

Conversion formula:

Key conversions:

• 1 ken = 1.818 m = 5.962 ft
• 1 ken = 6 shaku (尺)
• 1 ken = 60 sun (寸)
• 1 m = 0.55 ken

The architectural standard bay (1 ken wide) became the basis for the tatami mat system: 1 ken = half a tatami mat length (90 cm in Edoma) x 2 = 180 cm = 1 ken.

For shorter measurements, use our shaku and sun converter. For general length conversions (m, ft, inch), try the length converter. Room area calculations combine well with the tatami area calculator.

1. Enter the length in ken (e.g. 2 for a standard room bay).
2. Select the target unit.
3. Click Convert to see the result.
4. Compare with the architectural reference table.

How many meters is one ken?

One ken equals 1.818 m (exactly 60/33 meters = 20/11 m). This is 6 kane-jaku shaku, where 1 shaku = 10/33 m. In feet, 1 ken = 5.96 ft.

What is the ken used for today?

The ken is still used in traditional Japanese architecture (kiyomizudera, shrines, temples), heritage restoration, and by miyadaiku (shrine carpenters). Modern buildings use meters, but the ken module influences standard room dimensions.

What is the difference between kane-jaku and kujira-jaku?

Kane-jaku (metal ruler) = 30.30 cm, used for architecture and general measurement. Kujira-jaku (whale ruler) = 37.88 cm, used only for traditional tailoring and furniture making. The ken is always based on kane-jaku.

How is the ken related to tatami mats?

One ken (1.818 m) approximately equals the length of 1 tatami mat (Edoma = 180 cm). A standard room bay of 1 ken x 1 ken fits approximately 2 tatami mats. This is why the ken-tatami-area system is mathematically consistent.

Can I use ken for modern construction?

Modern Japanese building codes use metric units. However, some carpenters and designers still reference ken for traditional-style rooms (washitsu), engawa (verandas), and renovation of pre-war buildings. The ken is cultural, not legal.

The ken as architectural grid. Traditional Japanese buildings use the "ken-module" (間モジュール): pillar spacing is always in whole or half ken. A typical room is 1.5 ken deep x 2 ken wide (2.7 m x 3.6 m for Edoma standard).

Kiwari system. The kiwari (木割) method prescribes timber dimensions as fractions of the ken module. For example, a pillar diameter = 1/10 ken = ~18 cm. Roof beam depth = 3/10 ken = ~55 cm. This proportional system ensures aesthetic harmony.

Ken vs meter in modern building. Contemporary Japanese construction uses meters, but traditional carpenters (miyadaiku) still work in shaku and ken. Heritage building restoration requires the traditional system.

Two shaku systems. Architecture uses kane-jaku (30.30 cm). Traditional tailoring and carpentry use kujira-jaku (37.88 cm, also called "whale shaku" because measuring rulers were made of whale baleen). Always confirm which shaku is meant.