Shakkan-ho Pro: Tsubo & Shaku

Tsubo, shaku, sun — one tap away. A dedicated calculator that converts Japan's traditional shakkan-ho units, and the traditional units of 23 other countries and regions, to and from metric and imperial.

Tsubo and tatami to square metres for real estate, shaku, sun and ken on a building site, sho and go for rice and sake, momme for pearls — the units generic converters skip, all handled properly.

FIVE TABS
• Length: ri, cho, jo, ken, shaku, sun, bu, rin, mo ↔ metres / miles, yards, feet, inches
• Area: chobu, tan, se, tsubo, tatami, go, shaku ↔ m², ares, hectares / acres, square feet
• Weight: kan, kin, momme, fun, rin ↔ kilograms, grams / pounds, ounces, grains
• Volume: koku, to, sho, go, sai, cubic shaku ↔ m³, litres / gallons, pints
• Temperature: °C ↔ °F ↔ K, with a quick table for body temperature, ovens and weather

BUILT FOR REAL WORK
• Answers in traditional mixed notation too, such as 6尺1分 (6 shaku 1 bu) or 1升4合 (1 sho 4 go)
• Results open in the other system automatically: enter millimetres, get shaku; enter shaku, get metres
• Tap a result to copy it, or share the whole result to chat or email
• Running total: add several values on the spot (rooms, materials)
• Volume from length × width × height
• Quick-reference table on every tab
• A 30-second guide for first-time users
• "Your stats": counts, streaks and a title that grows as you use the app (stored only on your device)
• Conversions work offline

UNITS FROM AROUND THE WORLD
Switch the country or region to use its traditional units: Korean pyeong, Chinese jin and mu, Taiwanese ping and jia, Hong Kong catty and tael, bigha, katha and marla for India, Bangladesh, Pakistan and Nepal, plus land units for Indonesia, Vietnam, Egypt, the Dominican Republic and Cuba.

WHO IT'S FOR
• Real estate, construction and renovation work moving between tsubo and m²
• Stonemasonry, gravestone and landscaping estimates
• DIY builders reading old Japanese drawings
• Anyone comparing land units across countries

FEET + INCHES, STONES + POUNDS
Type 5 ft + 8 in or 11 st + 4 lb directly and get answers like 5 ft 8 in (5′8″). Cups, tablespoons, teaspoons, fluid ounces and troy ounces are included. New countries and regions: Thailand, Malaysia/Singapore, the Philippines, Myanmar, the Middle East, Türkiye, Iran/Afghanistan, Russia, Latin America/Spain and Brazil.

15 languages, no sign-up, free to use.