1 ping (坪) = 400/121 square meters (m²), about 3.3058 m²; conversely, 1 m² = 0.3025 ping. To convert m² to ping, multiply by 0.3025; to convert ping to m², multiply by 3.3058 (or divide by 0.3025). Property ownership certificates (權狀) and registration transcripts (謄本) always register area in m²; ping is the customary unit in sales and renovation. The public-area ratio (公設比) has no legal formula: the same home, calculated with different denominators, can come out almost twice as high.
Reminder: Ping is not a unit registered on the certificate. When signing, settling price differences or comparing prices, use the m² figures on the transcript or certificate and convert to ping yourself before comparing. How building area is measured and registered follows the latest rules of the Ministry of the Interior and the land administration offices (地政事務所).
How many square meters is 1 ping? Conversion formula and table
Government documents convert using 1 m² = 0.3025 ping. For example, the New Taipei City tax office (新北市稅捐處) and the Ministry of Finance tax portal (財政部稅務入口網) write 300 m² of urban land as "about 90.75 ping" and 700 m² as "about 211.75 ping", which is exactly × 0.3025. From this:
- 1 m² = 0.3025 ping = 121/400 ping
- 1 ping = 1 ÷ 0.3025 = 400/121 m² ≈ 3.305785 m², usually written 3.3058
The usual explanation is that 1 ping is a square with sides of 6 Taiwanese feet (台尺; 1 Taiwanese foot = 10/33 m), and (6 × 10/33)² is also exactly 400/121 m². However, this article did not find an official document that explicitly defines the ping, so the above is the commonly used conversion. Government registration of building area uses m² (Article 276 of the cadastral survey implementation rules, 地籍測量實施規則: the unit of building area is the m², recorded to the 2nd decimal place, with the 3rd decimal place rounded); ping is only the customary term in private sales and renovation.
| Ping | → Convert to m² | m² | → Convert to ping |
|---|
| 1 ping | 3.31 | 10 | 3.03 |
| 10 ping | 33.06 | 30 | 9.08 |
| 20 ping | 66.12 | 50 | 15.13 |
| 25 ping | 82.64 | 66 | 19.97 |
| 30 ping | 99.17 | 100 | 30.25 |
| 35 ping | 115.70 | 132 | 39.93 |
| 40 ping | 132.23 | 300 | 90.75 |
| 50 ping | 165.29 | 700 | 211.75 |
The figures in the table were calculated by this article from 1 ping = 400/121 m², rounded to 2 decimal places. For mental math, using "m² × 0.3" comes up about 0.8% short; 100 m² would be off by 0.25 ping, so for comparing large areas we recommend 0.3025.
How to read the areas on a property ownership certificate: main building, accessory buildings and shared areas
A building transcript or certificate registers the area in several pieces. Under Articles 273, 276 and 283 of the cadastral survey implementation rules, it works roughly as follows:
| Item | What it is | How it is measured and registered |
|---|
| Main building (主建物; area of each floor) | The interior of your own unit | Bounded by the outer edge of the exterior walls; where a wall separates you from a neighboring unit, bounded by the center of the shared wall (Article 273) |
| Accessory building (附屬建物) | Balconies and the like | Where the as-built drawings for the use permit (使用執照) show a balcony set up under the Building Technical Regulations (建築技術規則), the protruding part is bounded by its outer edge and measured as an accessory building (Article 273) |
| Shared areas (共有部分) | The "big public" and "small public" areas (大公、小公), such as the lobby, corridors, stairwells and mechanical and electrical spaces | Merged in groups according to what the unit owners agree, and measured under a separate building number (建號) (Article 283); each unit registers its share (權利範圍, "scope of rights") under the shared-area building number |
So the "total area" on a certificate is usually: main building + accessory buildings + shared areas × your share. The building numbers of the shared areas are listed separately, so when reading a transcript you need to add up "area × scope of rights" for every shared-area building number to get the public area allocated to you. For how to apply for transcripts, see How to apply for land and building transcripts.
Rain canopies and eaves: Current Article 273 lists only balconies as accessory buildings; its last paragraph provides that for buildings for which a construction permit application was filed before Jan 1, 2018, eaves, rain canopies and basement levels are still surveyed under the rules before the amendment of Jan 9, 2017. In other words, on the certificate of an older building you may see a rain canopy registered as an accessory building, while new projects that applied for a construction permit from 2018 onward follow the current rules.
How is the public-area ratio calculated? There is no legal formula
"Public-area ratio" is a market term, and this article found no regulation that sets a formula for calculating it. A press release issued by the Control Yuan (監察院) on Sep 3, 2009, on its censure of the Ministry of the Interior, says outright that how developers calculate the ratio in sales ads "is currently not regulated by law"; in practice some use the main building as the denominator, some use the main building plus accessory buildings, and some use the entire registered area.
In the same investigation, the Control Yuan ran numbers on an actual transcript for a unit in Da'an District, Taipei City (main building 139.85, balcony 21.15, rain canopy 15.93, shared areas totaling 83.221 m²), and the same unit produced four different public-area ratios:
| Denominator | Public-area ratio |
|---|
| Total registered area (main building + balcony + rain canopy + shared areas) | 31.99% |
| Main building + balcony + rain canopy | 47.04% |
| Main building + balcony | 51.69% |
| Main building only | 59.51% |
The most common formulation at present is the first: public-area ratio = shared-area size ÷ total certificate area × 100%. Some people first deduct the parking-space area registered within the shared areas, because parking is usually priced separately. These are customary market methods, not legal requirements; the following is this article's suggestion: when comparing two properties, recompute the ratio yourself from the transcripts using the same formula, and do not compare the numbers in ads directly.
Taking the unit above as an example, the main building's 139.85 m² is about 42.30 ping, but the total registered area of 260.151 m² is about 78.70 ping. When priced by total ping, nearly half of the money buys area outside the main building. When reading actual-price registration (實價登錄) data, also watch the denominator of the unit price; see How to look up actual-price registration, and how unit prices and parking are calculated.
Certificate ping, interior ping and actual usable area
- Certificate ping: the main building, accessory buildings and your share of the shared areas added together are the "how many ping" usually quoted in sales.
- Main-building ping: counts only the interior of your own unit, but it is measured to the outer edge of the exterior walls and the center of the walls between units, so it includes wall thickness.
- Actual usable area: the floor area where you can put furniture after deducting wall thickness, columns and pipe shafts. This figure is not registered on the certificate; you can only measure it yourself.
For estimating an air conditioner or dehumidifier, use the actual interior ping, not the certificate ping; you can estimate air conditioner tonnage with the AC tonnage calculator.
FAQ
How many square meters is 1 ping?
1 ping = 400/121 m², about 3.3058 m² (that is, 1 m² = 0.3025 ping, consistent with the conversion used by the Ministry of Finance tax portal). Certificates register area in m²; ping is the customary term used in private dealings.
How do I convert square meters to ping?
Multiply the m² figure by 0.3025. For example, 66 m² × 0.3025 = 19.965, about 20 ping; 300 m² is about 90.75 ping.
What public-area ratio counts as normal?
This article found no regulation that sets an upper limit or a uniform formula for the public-area ratio, so it does not offer a "normal range". When comparing properties, take your share of the shared-area size on the transcript ÷ the total certificate area, and calculate with the same formula yourself.
Are rain canopies still registered on the certificate?
Under Article 273 of the cadastral survey implementation rules, for buildings for which a construction permit application was filed before Jan 1, 2018, rain canopies and eaves are still surveyed under the old rules; the current text lists only balconies as accessory buildings. Whether new projects register them, go by the certificate and the explanation of the land administration office.
Why is the ping I bought different from what I measure?
The certificate ping includes your share of the shared areas and the balcony, and the main building is measured to the outer edge of the exterior walls and the center of the walls between units, so it is always larger than the floor area you actually measure indoors.
Last updated: 2026-11-01
This article was compiled by the SOSfix editors from public information and is for general reference only. For an individual case, contact the land administration office for the location of the building (the land administration offices under the Taipei City land administration bureau, 臺北市政府地政局, and the New Taipei City land administration bureau, 新北市政府地政局).
Sources
- National laws and regulations database (全國法規資料庫): cadastral survey implementation rules (amended Jan 13, 2023; verified 2026-11-01) (in Chinese): Article 273 on the boundaries for surveying buildings, balconies as accessory buildings, and the old rules for eaves and rain canopies of buildings permitted before 2018; Article 276 on area in m² recorded to the 2nd decimal place; Article 283 on separate building numbers for shared areas.
- Control Yuan: inflated "virtual ping" in housing; Ministry of the Interior censured on a motion by members 程仁宏 and 劉玉山 (98NEWS012, Sep 3, 2009, verified 2026-11-01) (in Chinese): the public-area ratio calculation "is currently not regulated by law" (as of 2009), the trial calculation with four denominators, and the area-to-ping figures.
- Ministry of Finance tax portal: must-read for tax saving, know the conditions for the preferential rate when selling self-use residential land (New Taipei City tax office, Sep 22, 2026, verified 2026-11-01) (in Chinese): the official wording of 300 m² as about 90.75 ping and 700 m² as about 211.75 ping.
- Ministry of Finance tax portal: tips for the tax refund when repurchasing a self-use residence (updated Sep 19, 2025, verified 2026-11-01) (in Chinese): the same conversion wording.
Related reading: Apartments vs Mansions vs High-Rises in Taipei · Taiwan Parking Space Types and Legal Transfer Guide
