calculacha! is an amazing calculator app from the creator of tweecha that lets you easily work out percentages!

English | Japanese

calculacha! is an amazing calculator app from the creator of tweecha that lets you easily work out percentages!

tweecha has been awarded #1 in Twitter app ranking.

For enquiries tweet @iam_o_sin (Please do not send emails or enquire within app reviews)


Screenshot_2014-05-30-03-36-03 Screenshot_2014-05-30-03-36-12 Screenshot_2014-05-30-03-36-32  Screenshot_2014-05-30-03-52-18Screenshot_2014-05-30-03-38-36


Download from Play store



You can easily calculate percentages!

You can calculate percentages easily! Incredibly handy! Below are examples.

  • Calculate the post-tax price of 5,500JPY (Japanese consumption tax is 8%): 5,500 + % = 5,940
  • Work out the 25% off price of 10,000JPY: 10,000 – 25 % = 7,500
  • What is 30% of 30,000JPY?: 30,000 * 40 % = 12,000
  • 43% of 120,000,000 people : 120,000,000 * 43 % = 51,600,000

Yes it’s true! This calculator can talk!

It reads out loud the key you’ve pressed or a search result you’ve tapped!

*To enable text-to-speech you need a Japanese text-to-speech software such as N2 TTS.

  • Install N2 TTS.
  • Open voice setting screen (upon installation it opens automatically. To set later go to Android settings > voice input/output > set text-to-speech)
  • Go to ‘Engine’, tick KDDILABS N2 TTS to enable.
  • Set default engine to KDDILABS N2 TTS.
  • Tap ‘Play Sample’ and check you can hear a Japanese voice.
  • Enable text-to-speech in calculacha!
  • Touch keys to check for sound.
I pressed the wrong key! Wrong digit! I want to do it again! Press clear button to cancel the last digit. Press and hold to clear all!

‘C’ button is the equivalent to ‘backspace’ key on a computer and deletes the last digit. Press hold to initialize value or calculation.

How many digits?! Input up to 24 digits, display up to 48 digits!

What would be a useful feature? Decimal calculation by typing in a denominator of a fraction.

For 1/2, key in 2/=, 1/3 is 3/=, 1/125 is 125/= and you get your decimals.

Type 1 million quickly! There is a ‘000’ button that lets you key in thousands.

You don’t see it much but this ‘000’ button is useful!

What was the last button I pressed? Displays last calculation on the top left side of the screen.

Displays status such as your calculation (*,/,+,-) and error (E), reset (C), calculation result (=).

I use plus-minus change button a lot.

It’s useful to have!

Displays 48 digits?! Changes font size automatically.

You see it a lot these days. I have built it in, too.

I know the one where you can do the last calculation again by pressing = button!

This function is available on most cauculators. After you pressed 1+5=, press = again and it adds 5 again.

Hold on, are there more hidden functions?!

Indeed, there are! You can change fonts! You can have Pi-chan on your screen! Find them!

You can also tweet. Find it in the menu!

Users’ Voices.



I wish!

Special Thanks (icons and fonts)

Icon: SMASHING – Freebie: E-Commerce Icon Set (33 Icons, PNG, PS, AI)


Future Plans


Known Problems

Not found.


2014-05-30 calculacha! v0.9.4-> Download

  • Show the AdMob banner with a probability of 1/2
  • Show the website in English the device not in Japanese mode
  • Show the AdMob banner the device not in Japanese mode
  • Show the GameFeat ads in landscape
  • Replaced English resources
  • Website in English complete
  • Replaced screenshots in English at play store
  • Changed link to website in English at description at play store
  • Advertise for foreign countries in AdMob
2014-05-27 calculacha! v0.9.3-> Download
  • Changed app name in English form “DENTAKU CCHA” to “calculacha!”
  • Changed about link to website in English
  • Changed link in tweet
  • Changed tweet message in English
  • Changed app name in English at play store

2014-05-25 calculacha! v0.9.2-> Download

  • Internal adjustment

2014-05-25 calculacha! v0.9.1-> Download

  • The operation of up to # 24 minority

2014-05-25 calculacha! v0.9.0-> Download

  • Added to menu: Give 5 stars!
  • Adjustment: Auto text size
  • Released at play store!

2014-05-24 calculacha! v0.8.0-> Download

  • Added to menu: vibration ON/OFF

2014-05-24 calculacha! v0.7.1-> Download

  • Reads out loud comments saved on clipboard.
  • Adjustment: text-to-speech steps.
  • Adjustment: text-to-speech start confirmation.
  • Adjustment: text-to-speech language confirmation.

2014-05-23 calculacha! v0.7.0-> Download

  • Restored font setting at start-up.
  • Restored text-to-speech setting at start-up.
  • Restored Pi-chan display setting at start-up.

2014-05-23 calculacha! v0.6.0-> Download

  • Now allows landscape view.
  • In case of no text-to-speech, N2TTS play store is displayed.
  • Adjusted vibration strength.
  • Added to menu: who is the author?
  • Added to menu: send a gift to author.
  • Added to menu: Japanese text-to-speech N2 TTS
  • Modified: resetting of display

2014-05-23 calculacha! v0.5.0-> Download

  • Usage analysis tweet
  • Pi-chan appears somewhere (please find him as this is a hidden function)
  • Prepared this introductory page for v0.5.0 release.

2014-05-22 calculacha! v0.4.0-> Download

  • Menu button is now always displayed (compatible with android 2.*, thanks to @takke’s article)
  • Icon display in menu.
  • Added to menu: save result to clipboard
  • Added to menu: text-to-speech ON/OFF
  • Added to menu: tweet
  • Added to menu: share
  • Turned off text-to-speech at start-up
  • Changed default font

2014-05-21 calculacha! v0.3.0-> Download

  • Changed app name from ‘DENTAKU CCHA’ to ‘DENTAKU CCHA!’ (provisional)
  • Set app icon (used material available for commercial use)
  • Switch between 15 different fonts (all changed to fonts that are available for commercial use. Try and find out how to change fonts!)
  • Text-to-speech when pressing button (internationalized)
  • Vibrate when pressing button
  • Tap result to be read out loud (internationalized)
  • Press and hold result and copy to clipboard
  • Added setting menu button on top right side
  • Link to app details from menu
  • Link to tweecha detail page from menu
  • Added icon ad
  • Added recommended app button
  • Added ad when closing app
  • Fixed to portrait view
  • Minor adjustment to layout and color.

2014-05-20 calculacha! v0.2.0-> Download

  • Changed button design
  • 9 different fonts available (Try and find out how you can change them!)
  • Minor adjustments.

2014-05-20 calculacha! v0.1.0-> Download

  • Percentage calculation available
  • Delete last digit, all clear available
  • Input denominator of a fraction
  • Input 24 digits, display 48 digits available
  • Auto font size correction available
  • 000 button available
  • Calculation status displayed
  • Plus-minus button available
  • = button lets you repeat last calculation
  • Screen design complete