There are already a lot of Unit Converter apps on Google Play. But most are inconvenient and difficult to use because of poor and complicated UI (user interface).
In fall 2013, I published Unit converter app that had most intuitive and simple UI.
This is a manual for smart tools package. I'm sorry that currency rate feature was removed because of lack of internet permission.
※ Introduction video
※ Supported unit groups
① Basic : length (distance), area, weight (mass), volume (capacity)
② Living : exchange rate, temperature, time, speed
③ Science : pressure, force, work (energy), power, torque, flow, density, viscosity
④ Misc. : angle, data, fuel consumption, cooking, illuminance, astronomy, radiation, prefix, binary
※ How to use it
1) Select a category (Basic / Living / Science / Misc.)
2) Select one of 4 groups.
3) Select one unit by LONGCLICK on the list or tap the selector.
4) Input the number with a keypad.
You can choose 4 favorites in Science and Misc. categories.
※ Landscape mode
If your device is a tablet PC or a phone with high-resolution (at least 960x540), this app supports landscape mode.
Go menu -> landscape.
※ How to input fractions
Length and weight unit groups have [. /] button on the keypad. You can input fractions.
1 2/3 =>  + [./] +  + [./] + ,
1/4 => [./] +  + [./] + 
2 lbs 6 oz =>  + [./] +  + [./] +  pounds
※ What's new?
- v1.2 : Favorites. 9 unit groups added.
- v1.1.11: Cooking, square mile, ksi, kip
- v1.1.10: µm, µg
- v1.1.9 : PB, tonne, square(au), tonne, dwt
- v1.1.8 : fl oz, hand(ie)
- v1.1.7 : daN, mm2, TR, Beaufort
- v1.1.6 : Decimal format, fractions.
- v1.1.5 : mil (da), daN (fr), block
- v1.1.4 : MW, cmH20, kg legna equiv.
- v1.1.3 : milisec, mi/gal, pt, ton, ft/min
- v1.1.2 : kWh, ms
- v1.1.1 : m/min, Gbit/s, kN
- v1.1.0 : Torque
- v1.0.10: dm, fluid oz (US), Btu/h
- v1.0.9 : mmH2O, kgf/cm2
- v1.0.8 : km/min, km/gal, pints, quarts
- v1.0.7 : inchHg, MW, cup
- v1.0.6 : packet, deg.min.sec, cup
- v1.0.5 : kcal/h, torr, square inch
- v1.0.4 : Work (Energy), Power
- v1.0.3 : tablespoon & teaspoon, stone
- v1.0.2 : kPa, MPa
- v1.0 : released (Nov, 2013)
When you have an unit that is essential to your job, feel free to contact me.