Shaku. Kan. Sho. Convert traditional Japanese units instantly.

Japanese Unit Converter lets you convert traditional Japanese units — shaku, sun, ken, ri, kan, monme, sho, go, tsubo, tan, and many more — to and from metric and imperial units in seconds. Pick a category, choose your from and to units with the pickers, enter a value, and tap Convert. Covers 11 categories including length, mass, area, volume, temperature, time, speed, energy, pressure, data storage, and data transfer rate — over 100 units in total.

Download on the App Store

Get it on the App Store

Download on the App Store

Comprehensive Traditional Japanese Units

Length: ri, cho, ken, jo, hiro, shaku, sun, bu, rin, mo, kujirajaku, tan (fabric), and hiki. Mass: da, kan, kin, ryo, monme, fun, and rin. Area: tsubo, jo (tatami), se, tan, and cho. Volume: koku, hyo, to, sho, go, shaku, isshobin, and yongoubin. All the units you encounter in historical documents, architecture, and everyday Japanese life.

11 Categories, 100+ Units

Length, mass, area, volume, temperature, time, speed, energy, pressure, data storage, and data transfer rate — all in one app. Beyond Japanese traditional units, the app also covers imperial units (inch, pound, gallon), astronomical units (light-year, AU, parsec), and data units (KB, MB, Mbps, GB/s).

Pick Units, Enter a Value, Tap Convert

Select a category, choose your source and target units from the pickers, type a value, and tap the Convert button. Results are displayed to six decimal places so even precise conversions are accurate. Temperature uses a proper offset formula — not a simple ratio — for correct Celsius, Fahrenheit, and Kelvin results.

Everything on One Screen

Category picker, from-unit picker, input field, to-unit picker, and result — all visible on a single screen with no page navigation. No account required, no setup, no clutter. Open the app and start converting immediately.

Japanese length units — all of them, in one place.

The length category covers ri, cho, ken, jo, hiro, shaku (kanejaku), sun, bu, rin, mo, shi, kujirajaku (whalebone shaku used in tailoring), and tan and hiki (fabric length units). SI units cover meter through nanometer. Imperial units include mile, yard, foot, inch, and nautical mile. Astronomical units include light-year, AU, and parsec — all in the same picker.

LENGTH
MASS / AREA / VOLUME

Mass, area, and volume — traditional and modern together.

Mass units run from da and kan down through kin, ryo, monme, fun, rin, and mo, alongside carat, troy ounce, pound, and ounce. Area covers tsubo, jo (tatami mat), se, tan, and cho alongside square meter, hectare, acre, and square foot. Volume includes koku, hyo, to, sho, go, and shaku — plus isshobin (1.8 L bottle), gougoubin (0.9 L), and yongoubin (0.72 L) for practical sake-bottle conversions.

Temperature conversion with correct offset math.

Celsius, Fahrenheit, and Kelvin are converted using the proper offset formula — Kelvin as the intermediate base — not a naive proportional calculation. So 100 °C correctly returns 212 °F, and 98.6 °F correctly returns 37 °C. If you've been burned by apps that get temperature wrong, this one handles it correctly.

TEMPERATURE
DATA

Data storage and transfer rate conversions too.

Storage units use 1 KB = 1024 bytes: bit, byte, KB, MB, GB, TB, and PB. Transfer rate units use 1 kbps = 1000 bps: bps, kbps, Mbps, Gbps, Tbps, B/s, KB/s, and MB/s. Useful for IT and networking work where you need to move quickly between storage and throughput figures.

Pick a category. Choose your units.
Enter a value and convert.

3 Steps to Get Started

1
Choose a category

Tap the category picker at the top of the screen and select the type of unit you want to convert — length, mass, area, volume, temperature, and so on. The unit lists update automatically to show only the units in that category.

2
Select your from and to units

Use the "From" picker to select the unit you're converting from, and the "To" picker to select the target unit. Type the value you want to convert into the input field. Decimal values are fully supported.

3
Tap Convert and read the result

Tap the Convert button at the bottom of the screen. The converted value appears immediately, displayed to up to six decimal places. Change units or enter a new value and tap Convert again for instant recalculation.

Get it on the App Store

Download on the App Store

What Users Are Saying

"I work with old architectural drawings that use ken and shaku, and I used to have to look up the conversions every single time. This app solved that completely. Having shaku, sun, and ken all in the same picker alongside meters is exactly what I needed."

— architect_tanaka

"I was researching sake bottle sizes and kept running into sho, go, and koku without knowing the metric equivalents. The fact that this app includes isshobin and yongoubin as actual units blew my mind. Perfect for this kind of deep-dive research."

— sake_enthusiast_sato

"The temperature conversion is correct — that's rarer than it sounds. I've tried other apps that get Fahrenheit-to-Celsius wrong because they don't handle the offset properly. This one does it right. I also use it for data size conversions at work, so it covers a lot of ground."

— engineer_yamada

Frequently Asked Questions

Find answers to common questions below.

QWhat unit categories does the app cover?
AThe app covers 11 categories: length, mass, area, volume, temperature, time, speed, energy, pressure, data storage, and data transfer rate. Each category includes traditional Japanese units alongside metric, imperial, and other internationally used units.
QIs the temperature conversion accurate?
AYes. The app uses a proper offset formula with Kelvin as the intermediate base value, not a simple ratio. This means Celsius, Fahrenheit, and Kelvin are all converted correctly — including edge cases like 0 °C = 32 °F = 273.15 K.
QHow many traditional Japanese units are included?
ALength includes ri, cho, ken, jo, hiro, shaku, sun, bu, rin, mo, shi, kujirajaku, tan (fabric), and hiki. Mass includes da, kan, kin, ryo, monme, fun, rin, and mo. Area includes cho, tan, se, tsubo, jo (tatami), go, and shaku. Volume includes koku, hyo, to, sho, go, shaku, isshobin, gougoubin, and yongoubin.
QHow many bytes is 1 KB in the data storage conversion?
AThe data storage category uses 1 KB = 1024 bytes (binary definition). The data transfer rate category uses 1 kbps = 1000 bps (decimal definition), which matches how network speeds are typically marketed and measured.
QCan I enter decimal values?
AYes. The input field uses a decimal keyboard, so you can enter values with a decimal point. Results are displayed to up to six decimal places, making the app useful for precise calculations as well as quick estimates.

Get it on the App Store

Download on the App Store
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