A single plot of Taiwanese land gets described in three different units at once: the deed prints square metres, the agent quotes ping, and farmland registers in jia — then foreign sources add hectares and acres on top. This converter stocks eight units — square kilometre, square metre, square centimetre, hectare, ping, jia, square mile and acre — with the square metre as the base. Pick the unit your figure is in and the other seven line up at once. It runs in your browser, so the areas you type never leave the tab; the page itself continues to load third-party resources such as advertising as usual.
How to use it
- Put the area into the Value field, which starts at 1. Deed figures such as 99.17 can be entered as they are.
- The From unit dropdown starts on Square Meter. Switch it to whatever the document in front of you uses — Square Meter for a land register extract, Ping for an agent's quote.
- Seven cards below give every other unit at once, each with its own copy button. Working through a whole deed, change only the number; the unit selection stays put.
- To confirm you have not inverted the direction, enter 1 hectare — the Ping card should land close to 3025.
- An empty field puts a dash on every card, and copying then gives you an empty string.
When it comes in handy
Turn the square metres on a deed into ping
Taiwanese building deeds are always registered in square metres, yet viewings, comparisons and price-per-unit talk all happen in ping. 99.17 m² is about 30 ping, and 30 ping is 99.17355 m² going back. Convert the main structure, the attached areas and the common share separately — converting only the total throws away the basis for comparison.
Move between jia and hectares for farmland
Land registers and older farmers work in jia, while agricultural subsidies, zoning maps and international datasets use hectares. One jia is 0.969917 hectares, 2933.999035 ping or 2.396717353 acres — about 3% short of a hectare, which is not a gap you can wave away on a subsidy application.
Compare renovation and material quotes
Flooring, tile and paint are quoted per ping by some suppliers and per square metre by others, which makes the two bids incomparable as printed. Convert both to the same unit before dividing by the total. Remember that one ping is 3.305785 m², so a price difference feels three times larger than it is until you normalise.
Read foreign land and farm figures
US and Australian farmland is measured in acres — one acre is 4046.856 m², or 1224.173986 ping — while EU agricultural statistics use hectares, one of which is 2.471054073 acres. Wildfire extents and development sizes in foreign news make far more sense once converted to hectares or square kilometres.
Limits and behavior
- The ping and jia constants are stored rounded (1 ping = 3.305785 m², 1 jia = 9699.17 m²) while the exact definitions are fractions: one Taiwanese chi is 10/33 m, and a ping is six chi square, so 400/121 = 3.30578512… m². Ten significant digits are enough to show the truncation — **one hectare converts to 3025.000113 ping rather than a clean 3025**, and 100 m² comes out as 30.25000113 ping. The error is around four parts in ten million, so no property deed is affected.
- For the same reason, one jia reads 2933.999035 ping, whereas by definition a jia is exactly 2934 ping (ten fen, a hundred li). For land registration or contract arithmetic, use the defined 2934 rather than the converted figure.
- **Square feet are not offered.** Property listings in Hong Kong, Singapore and the United States lead with sq ft, so convert by hand when you need it: 1 m² = 10.7639 sq ft, and one ping is roughly 35.58 sq ft. Square yards and square inches are likewise absent.
- Neither are the subdivisions below jia — fen (a tenth) and li (a hundredth) — nor the mainland Chinese mu of about 666.67 m². Reading "mu" in a simplified-Chinese source as if it were a jia overstates the area by more than fourteen times.
- An area ratio is not a length ratio. A foot is 0.3048 m, but a square foot is 0.09290304 m²: the factor has to be squared. Carrying a number over from the length converter produces spectacularly wrong results.
- Very small results print in JavaScript's scientific notation — one square centimetre in square kilometres shows as 1e-10. That is formatting, not a loss of precision.
- This tool converts numbers; it does not interpret what a ping **contains**. The 30 ping on a deed bundle the main structure, attached areas such as balconies, and a share of common space, leaving usable interior floor closer to 70% of the headline. That is a registration convention, not a conversion problem.
Frequently asked questions
Why is one hectare 3025.000113 ping instead of exactly 3025?
Because the ping constant is stored as 3.305785 while the exact value is 400/121 = 3.3057851239669… square metres, with the tail cut off. 10000 ÷ 3.305785 is 3025.000113, and ten significant digits are enough to show it. Why a fraction like 400/121? A ping is defined as six Taiwanese chi square, a chi is 10/33 of a metre, and (60/33)² reduces to 400/121, which simply does not divide out. The error is four parts in ten million: a 100 ping plot is off by less than 0.0004 m², which no transaction will ever notice.
Is a jia not exactly 2934 ping? This shows 2933.999035.
The definition really is 2934 ping. The jia was fixed at 2934 ping during the Japanese colonial period and subdivided into ten fen and a hundred li, which makes the exact metric value 2934 × 400/121 = 9699.1735537 m². The code stores 9699.17, dropping 0.0035537, and dividing that by the equally truncated ping constant lands on 2933.999035. The two constants were rounded in different directions, so the errors do not cancel. In short: use this to get a feel for the area, and the definition to write the contract.
Where are square feet? I am looking at Hong Kong and Singapore listings.
Not here. The only imperial areas in this table are the acre and the square mile, both large-scale units, whereas apartment ads across Asia quote the much smaller sq ft. The factor you need is 1 m² = 10.763910 sq ft, which is simply 1 ÷ 0.3048². A typical Hong Kong 500 sq ft flat is about 46.45 m², or 14.05 ping. One warning before you compare: those listings distinguish gross floor area from saleable area, and the two differ substantially, so check you are converting like for like.
The deed says 30 ping — do I get 30 ping to live in?
No, and this has nothing to do with conversion. A Taiwanese deed figure normally sums the main structure, attached areas such as balconies and canopies, and a share of common space. In newer towers the common share alone often exceeds 30%, and walls take their cut too, so the floor you can actually stand on is frequently in the low twenties. This tool faithfully turns 30 ping into 99.17355 m² and has no way of knowing how that 30 was assembled. When comparing properties, compare main-structure areas, or at least check the two common-share ratios are similar.
How do jia, fen, li and mu relate to each other?
The Taiwanese ladder is 1 jia = 10 fen = 100 li = 2934 ping, and only the jia is stocked here, so divide by 10 or 100 for the others. The mainland Chinese mu belongs to an entirely separate system: roughly 666.67 m², with 15 mu to the hectare. It is neither a fen (about 969.9 m²) nor anything close to a jia, which is more than fourteen times larger. Simplified-Chinese agricultural and e-commerce listings quote mu constantly, and reading it as jia inflates the area by an order of magnitude — the unit is deliberately not offered here so that mistake cannot happen silently.