Taiwanese foot (台尺) to centimetres
Convert 台尺 to centimetres. One Taiwanese foot is exactly 10/33 of a metre — 30.303 cm, not the 30.48 cm of an English foot.
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The formula
centimetres = 台尺 × 30.30303…The exact definition is a fraction:
1 台尺 = 10/33 m = 30.3030303… cmThe 台尺 is the Japanese shaku, defined against the metre as exactly 10/33 and brought into Taiwan during the colonial period. The decimal repeats forever; the fraction does not.
Three units get called a foot or an inch
| Unit | Centimetres | Where |
|---|---|---|
| 台尺 | 30.3030 | Taiwan |
| 市尺 | 33.3333 | mainland China |
| English foot | 30.4800 | imperial |
The 台尺 and the English foot are only 0.6% apart, which is close enough to pass unnoticed over a single measurement and far enough to accumulate over a run of joinery. The 市尺 is 10% longer than either.
The same applies one level down:
| Unit | Centimetres |
|---|---|
| 台寸 | 3.0303 |
| 市寸 | 3.3333 |
| Inch (英吋) | 2.5400 |
An inch and a 台寸 differ by nearly 20%, and in Chinese the two are distinguished only by which character is used — 吋 for the English inch, 寸 for the traditional one. Screens, pipes and clothing use 吋; carpentry uses 寸.
Quick reference
| 台尺 | Centimetres | Metres | English feet |
|---|---|---|---|
| 1 台尺 | 30.30 cm | 0.303 m | 0.994 ft |
| 2 台尺 | 60.61 cm | 0.606 m | 1.989 ft |
| 3 台尺 | 90.91 cm | 0.909 m | 2.983 ft |
| 5 台尺 | 151.52 cm | 1.515 m | 4.972 ft |
| 6 台尺 | 181.82 cm | 1.818 m | 5.966 ft |
| 10 台尺 | 303.03 cm | 3.030 m | 9.943 ft |
| 33 台尺 | 1000 cm | 10 m | 32.808 ft |
33 台尺 is exactly 10 metres, which is the definition read backwards and the easiest check that a conversion is right.
Where it is still used
The 台尺 is not nostalgia. It is the working unit for:
- Carpentry and joinery. Timber is cut and sold to 台尺, and a carpenter’s rule is marked in 台尺 and 台寸.
- Doors, windows and cabinets. Standard openings are dimensioned in 台尺.
- Altars and shrines (神桌). Sizes are chosen against the auspicious-measure scale printed on a 文公尺, which is divided in 台尺.
- Beds and furniture. A “五尺” double bed is 151.5 cm wide.
| Furniture | 台尺 | Centimetres |
|---|---|---|
| Single bed width | 3 台尺 | 91 cm |
| Small double | 4 台尺 | 121 cm |
| Standard double | 5 台尺 | 152 cm |
| King | 6 台尺 | 182 cm |
It is where the 坪 comes from
A 坪 is six 台尺 square:
6 台尺 = 60/33 m = 20/11 m
1 坪 = (20/11)² = 400/121 m² = 3.3058 m²Which is why the area conversion is exact and why a hectare is exactly 3025 坪. See ping to square metres.
Estimating in your head
Multiply by 30. 6 台尺 × 30 is 180 cm against a true 181.8 — 1% low. Or use the definition: divide by 33 and read the answer in tens of metres.