# Unit Converter (tsubo, tatami, inch, °C) 1 tsubo = 400/121 m² (about 3.305785 m²). A tatami varies by region and standard, so each standard has its own row. 1 go is about 180.39 mL. - URL: https://tools.itlibra.com/en/unit-converter - On-device・No upload - Last updated: 2026-10-24 ## How to use 1. Choose a unit type such as Length or Area. The common units are listed first, and a link from search opens its type directly. 2. Type a number in any unit. Every unit of the same type is converted at the same time, and you can type into any row. 3. Pick 4, 6 or 10 significant digits. The default is 10, and trailing zeros are removed. 4. Open “Definition and source” under a unit to read its formula. Where a unit is based on a law or a published standard, its source is given too. 5. Use the quick table for typical values, and the copy button on a row to copy one value. ## Use cases - Convert a flat size from tsubo to m² to compare with a floor plan - Estimate the area of a room from its number of tatami mats - Convert US or UK sizes (inches, pounds, °F) to metric - Measure a recipe’s go or tablespoon amounts in millilitres - Compare fuel economy figures written as km/L, L/100 km or mpg ## What it does ### Every unit of a type at once Type a number in one row and every unit of that type updates: metres, feet, inches, shaku, ken and ri for length, or tsubo, m², tatami by standard, tan and chō for area. You can type into any row. ### Exact fractions, rounded only for display Each unit is held as an exact ratio to its base unit (for example 1 inch = 0.0254 m and 1 tsubo = 400/121 m²). No floating-point error is used; results are rounded to the chosen significant digits. ### Tatami shown by standard A tatami varies by region and standard, so the real-estate advertising basis (1 tatami = 1.62 m² or more) and the typical Kyoma, Chukyo, Edoma and Danchi sizes each have their own row. ### Temperature and fuel follow their formulas °C, °F and K use the offset formulas (affine), and L/100 km is the reciprocal of km/L. A temperature below absolute zero and a fuel economy of 0 are reported as errors. ### A definition and source for each unit Open “Definition and source” under any unit to read its formula. Units based on a law or a published standard give the source, and units that need care in trade have a note. ## Capability matrix | Feature | Support | Notes | | --- | --- | --- | | Length, area, weight, volume (cooking), temperature, speed, fuel economy and energy | Supported | — | | Tatami (each standard gives a different value; the size varies by region and building) | Partial | Typical sizes, not a legal definition | | Traditional Japanese units (shaku, tsubo, kan, go and others) | Partial | Whether they may be used in trade or certificates depends on the Measurement Act. Reference only | | Currency conversion (exchange rates) | Not supported | Exchange rates need a network connection, so they are not handled here | | Data size conversion (MB, GB and so on) | Not supported | See the related IT Calculator below | | Date and time conversion | Not supported | See the related Date & Time Studio below | | Input in exponent form, such as 1e3 | Not supported | Type digits, a decimal point and a sign | ## Limits & notes - Input is limited to 40 characters. Results can show 4, 6 or 10 significant digits (default 10). - Negative values are accepted for temperature (°C and °F) only. A temperature below absolute zero (0 K) is an error. - A fuel economy of 0 (L/100 km or km/L) cannot be converted. - Very large or very small results (below 1e-9 or 1e18 and above) are written in exponent form, such as 1.5e+18. - Units not listed here, and national or local units that are not on the list, are not included. ## Privacy & safety Numbers you type are calculated only in your browser. Nothing is sent to or stored on a server, and the numbers are not put in the URL (only the unit type is). ## FAQ ### How do I convert tsubo to square metres? 1 tsubo is a 6-shaku square, which is 400/121 m² (about 3.305785 m²). So multiply the tsubo figure by 3.305785. One square metre is about 0.3025 tsubo. ### How many square metres is a tatami mat? It depends on the region and the standard. In Japanese real-estate advertising, a tatami is counted at 1.62 m² or more under the fair-competition code. Typical sizes are 1.82405 m² (Kyoma), 1.6562 m² (Chukyo), 1.5488 m² (Edoma) and 1.445 m² (Danchi). “Two tatami per tsubo” is only a rule of thumb. ### How many millilitres is one go? One go is one tenth of a shō, about 180.39 mL. A rice cooker’s “1 go” cup holds about 180 mL. A Japanese cooking tablespoon is 15 mL and a teaspoon is 5 mL. ### How do I convert inches to centimetres? 1 inch is exactly 2.54 cm. For example, 12 inches is 30.48 cm. ### What is the formula for Fahrenheit to Celsius? °C = (°F − 32) × 5 ÷ 9. For example, 212 °F is 100 °C, and 98.6 °F is 37 °C. Absolute zero is 0 K, which is −273.15 °C. ### How accurate are the results? Each conversion uses exact ratios and fractions, and the result is rounded only for display, to 10 significant digits by default. Floating-point errors such as 0.1 + 0.2 do not appear. Each unit’s formula is shown under the unit, with its source where there is one.