simplemobiletools/simple-calculator

A calculator for quick simple calculations with a nice user interface and no ads

Simple Calculator

This stylish modern calculator offers great user experience that you will love seeing. You can copy the result or formula to clipboard by long pressing it. You can also use this calculator as a currency converter to calculate your daily income and other amount in different country's currency. With eye soothing dark theme, it is now easy for you to see buttons and numbers more easily and use this calculator for simple calculations or use it as a currency converter or as a calculator and graphing calculator. You can also use this math calculator as a mortgage calculator

The app is a simple helper for fast calculations with many basic functions including multiplying, dividing, root and powers. It also comes with dark theme so that you can use this new technology to make your calculator look more smooth and easy to use rather than using sharp colors provided in different calculators that can't help you concentrate on your complex calculations in this graphing calculator and math calculator.

You can make it vibrate on button presses to make you confident during inserting your values. The exquisite colors used in this app are cool and look smooth to eyes so you can easily distinguish between all the buttons and calculate with ease. This calculator can be used to solve complex root problems or it can also be used as currency converter or graphing calculator.

There is an option in setting to prevent the phone from sleeping while using the app for comfortable usage and keep working on your complex problems in this currency converter and graphing calculator plus math calculator.

The text color of the resizable widget can be customized, as well as the color and the alpha of the background. Press the result or formula in the widget to open the app.

You can access a history of the operations to quickly scan through recent calculations.

It comes with material design and dark theme by default, provides great user experience for easy usage. The lack of internet access gives you more privacy, security and stability than other apps.

Contains no ads or unnecessary permissions. It is fully opensource, provides customizable colors.

Features:

• Easy to use calculator.
• Operations history
• Comes with dark theme to allow smooth usage of calculator.
• Works as a currency converter to help you calculate your incomes and other amounts.
• Can be used as a graphing calculator to calculate graphs quickly.
• Customizable text color to make it look more cool and according to your needs.
• Buttons sized according to the average finger tapping on screen to make calculations more comfortable.

Check out the full suite of Simple Tools here:
https://www.simplemobiletools.com

Facebook:
https://www.facebook.com/simplemobiletools

Reddit:
https://www.reddit.com/r/SimpleMobileTools

Telegram:
https://t.me/SimpleMobileTools

simple-calculator's Issues

Make sure √9= doesnt convert into 9√9

order of operations

Order of operations doesn't seem to work.
Example: 2+3*4 result is 20, but that's wrong. The correct result should be 14.

When you hold "-" number should turn negative (or something similar)

Feature request:
There should be a way I could turn a number negative. For example in my physical I can do a calculation press "-" then "=" and my number turns negative. I'd suggest that just holding "-" would turn the number negative.

Multi Selection not working

Hi very nice app but there is a bug.

in DayActivity.java if you multiselect items they are never getting deleted .
Only if you select one item it works. Also i´m getting a database error while selecting multiply items.

In DBHelper i have changed deleteEvent to make it working if i select multiply items like this:

public void deleteEvents(String[] ids) {
StringBuilder placeholders = new StringBuilder();
for (int i = 0; i < ids.length; i++) {
if (i != 0)
placeholders.append(", ");

        placeholders.append("?");
    }
    final String selection = COL_ID + " IN (" + placeholders.toString() + ")";
    db.delete(TABLE_NAME, selection, ids);
    db.close();

   if (mCallback != null)
      mCallback.eventsDeleted(ids.length);
}

greets frank

Add scientific calculator

[Feature request] Talking calculator

I will switch to this calculator and donate if you can make it talk. There are others in the play store that do so but they are buggy and full of ads. One even calls me dear which is a bit creepy.

The organisation I volunteer for (AilityNet),'s clients would appreciate this as well since most of them have limitations due to their conditions.

[Bug] NaN error

To reproduce the bug:

1. input -1
2. square root
3. result NaN
4. clear with C
5. Fatal Exception: main - Invalid double: "Na"

I also believe there is a confusing behaviour with negative numbers

2.0.0 tags wrong commit

Version tagged as 2.0.0 has the same version name and code as 1.12. This prevents Simple Calculator from being updated on F-Droid.

Could you delete 2.0.0 tag and tag commit a00eb5e as 2.0.0? This won't rewrite git history.

"π" and "e" numbers

Please add them in!

New logo

Hi, @SimpleMobileTools I am a graphic designer, I want to help others in graphic design.

After I reviewed your project, Your logo is very simple and not interested. Therefore I want to contribute to this project by creating a new logo / icon. what do you think?

whenever i use more than one operands the application crashes.

this is my simple java calculator.
if i do small calculation like:
9+1
7*2
6/2
it works absolutely fine, but if i enter two operands it crashes
like if i enter "9+1" and after i enter another "+" the application crash.
Please Help!!!

app crashing during sqrt operation

Non ho esattamente chiaro quasi sia l'operazione che sta cercando di eseguire. Se il risultato dell'operazione precedente è un numero negativo e l'operazione successiva è una radice l'applicazione va in crash.
Esempio di sequenza che manda in crash: -1 = then sqrt (any number) instantly closes app

app version: 5.0.2

Bug with the operator - App Crash

Hi,

Application should not allow multiple operator append.
In my test, it simply allows the operators to be clicked multiple times (its ok, if you can invalidate or something and append only once within an equation and calculate before the next operator can be applied).

Now after this if I click on OK. the app crashes. (Tested on Lenovo K3 Note Device + Emulators)

N Baua

Please add % button

square root is far less used than %. as there are much more SIMPLE usages of % than of sr.
please add % ( or replace root button with it).thanks

operator priority

multiplication/division should have priority over addidtion/subtraction

to test: enter something like 2+2*3
correct result would be: 8
current result is: 12

Add optional result-as-type

"Purchase Simple Thank You" bug?

Hello,

After upgrading to android 11, this error happened (didn't occur on android 10), it displays Purchase simple Thank You at top of settings, with shared theme not working.

This same issue occurs with Clock and Voice Recorder, however it does not occur with Gallery, Calendar, or dialer. As for other simple apps, i dont know.

I have tried uninstall, reboot and reinstall of both the app and the thank you app. I have installed the latest version availible of each from Fdroid, stable versions.

I have a pixel 4, android 11 october update.

Add more features and make the calculator more kiddy interface

I want to implement 3 features to this calculator which

1. able to view fraction or division as in pie diagram for better visual.
2. to have voice when letters are type.
3. to change all the variable into a more kid like interface, such as * into X and a fancy font.

thank you

Add history

FAQ entry for clearing data?

It took me a long time to accidentally find out that pressing the C for a longer time clears the input at once.

I was tapping the C shortly endlessly to operate like a backspace to clear the screen every time i wanted to start a next calculation.

Is this long-press-on-C-to-clear-at-once functionality worth a FAQ entry? I could add it and also create the Dutch translation.

Fix a glitch at the calculations when C is used

Steps to reproduce:

1. Enter "1"
2. Select addition (+)
3. Enter 1.55
4. Press C
5. Enter 1 (display shows: "1.51")
6. Press equals (=)

Expected output: "2.51"
Actual result: "3.01" (1.5 + 1.51)

Cannot install on Android 11

Cannot install on Android 11. The apk install gives the following adb log -

adb: failed to install ../com.simplemobiletools.calculator_36.apk: Failure [INSTALL_PARSE_FAILED_NO_CERTIFICATES: Scanning Failed.: No signature found in package of version 2 or newer for package com.simplemobiletools.calculator]

This may be helpful - https://stackoverflow.com/questions/2914105/what-is-install-parse-failed-no-certificates-error

Add brackets

Brackets are pretty important even for simple operations, would be good to have. It doesn't need to be a scientific calc but brackets are quite basic.

Make symbols appear in input

For example if you type "5+2" only "5" appears in input window. It would be more intuitive and more mistake-proof if all your inputs appeared on-screen in real time.

Clears everyting on the screen

Add a button that clears the result on the last operation on the first click, and clears the all history on the second click

Dividing by Zero Returns Zero as a Value

Expected Behavior

Dividing by Zero returns an Error or indication of invalid calculation.

Actual Behavior

Dividing by Zero returns an answer of 0.

How to Reproduce

1. Launch Simple Calculator 3.1.1 on Android 8.1.0
2. Tap '5' > Tap '÷' > Tap '0' > Tap '='

---

Device: Pixel 2 XL
OS: Android 8.1.0
App Version: 3.1.1

---

Recording of the Bug

---

Posted on Utopian.io - Rewarding Open Source Contributors

---

App name not translated

This app is the only one of your Simple apps that doesn't use the translated app name after the installation. It just shows up as "Calculator" although the German name should be "Rechner".

add tan-1(arctan),sin-1(arsin),cos-1(arccos) features

Scientific calculator does not include tan-1(arctan),sin-1(arsin),cos-1(arccos) features

Use regional format as decimal mark

In Germany, comma , is used as a decimal mark and dot . is used as a digit grouping marker.
E.g. 1.234,56 is one thousand two hundred thirty four point five six.
https://en.wikipedia.org/wiki/Decimal_separator#Examples_of_use

Ideally, the decimal separator is set by the used language, but an option to change the decimal and grouping marker would clearly enhance the user experience.

ERROR:Simple-Calculator-master\keystore.properties(Can not find the file)

I can not run project :/ When I tried start gradle build i take a Error: Simple-Calculator-master\keystore.properties

Multiplication/division with negative numbers

Hi

I wanted to do a multiplication or division with negative numbers, but Simple Calculator v4.1.0 doesn't recognize the arithmetic operator for multiplication or division in between negative numbers.

Examples:
Entering -100 / -5 will become to -100 -5 = -105
Entering -100 * -5 will become to -100 -5 = -105

Calculator Widget Issues starting with 5.1.2 release

The Simple Calculator widget has always worked just fine on my Android 7.1.2 (Lineage based ROM.) But I've noticed that the widget doesn't work correctly on Android 9 (OnePlus 6; with the last version of Oxygen OS 9 and/or with a Lineage 16/Android 9 based custom ROM.) I think it might be due to changes in Android 9? (I am not sure.)

Edit: It is not just Android 9, Simple Calculator Version 5.1.0 widget works perfectly on Android 9, the widget broke in version 5.1.2 and remains broken in the latest 5.1.3 release. I don't know how to fix it or I'd offer to help. I don't know anything when it comes to GUI stuff 🤔.

I use F-Droid releases (no 5.1.1 on F-Droid) but 5.1.1 on Github the widget works fine as well. So version 5.1.2 broke the widget somehow. I hope that helps narrow down what might have caused this.

Additionally: I updated Simple Calculator on my Lineage based Android 7.1.2 ROM (a Samsung Galaxy S5 with hack unlocked bootloader.) The latest Simple Calculator (5.1.3, from F-Droid) widget works just fine on my Android 7.1.2 phone. So I think this might be a combination of a bug introduced in the 5.1.2 calculator release that only seems to be an issue on Android 9 (and probably 10.) Unfortunately I have no other devices to test with, so that's as much info as I can gather for now.

This is best described with pictures (screenshots.)

When I first boot my phone (3 different Android 9 based OnePlus 6 phones) the calculator widget that I placed out on the screen just shows the black letters as seen (you can also see when I click the buttons, but no numbers show up.):

When I press and hold on the widget (such that the resize/remove options pop up) then the colors come back and the numbers I typed show up:

I hit divide, 2 and equals keys (to divide by 2) nothing happens until I click and hold on the widget in the same manner. Only then does the calculator widget show the numbers and operations that I typed in it.

The calculator app works just fine, but I miss the convenience of having the widget on my phone. Unfortunately I don't know why it does this and I have no idea how to fix it. I just wanted to make you aware (if you weren't already.) I appreciate your apps and how much work you put into them. I don't expect you to fix this or anything; I just wanted to let you know is all.

Thanks.

Edit: I just noticed that on my Android 7.1.2 phone I have Simple Calculator 5.1.0 (where I had 5.1.3 on all my Android 9 phones.) I downgraded my Lineage based (Android 9) Syberia OS OnePlus 6 phone to Simple Calculator 5.1.0 and now the widget is working just fine. So something broke the widget between 5.1.0 and 5.1.3... I'm not sure which release broke it, but I'll do some testing and find out.

Edit: Simple Calculator version 5.1.2 broke the widget (F-Droid builds) while 5.1.0 works perfectly. I'm changing my title to reflect the calculator version issue instead of Android 9 being the problem.

Add memory operations (M+, M-, MR, MC)

TAE

https://instagram.com/stories/vv_3095/2437063737994616892?utm_source=ig_story_item_share&igshid=8jflkl5qckby

Suggestion: Show ongoing operation on screen.

It's simple but I think is weird the app doesn't show whatever operation I'm doing. For example, I want to calculate 20 + 5, the app doesn't show when I hit the "+". It will only show 20, then register my operation silently, then the 5. This is odd, and I think it can be easy solved with just displaying the current operation on screen. Thanks.

Add its Toggle button and popup window and floating bubble

Please add its toggle button.
For open small calculator
popup window with floating button.

[Bug] Using operator before input sets first input to zero

If you use any operator (+,-,mod,^,...) before you input a digest you set the input to zero.
An example
The squareroot of 9 is 3. To get to this stunning conclusion you would normally press

9
√

And as a result get 3.
If you press

√
9
√

You get √0
You can do this with every operator

%
9
√

Add infinite accuracy

Better do it now. It will be even harder to implement later.

The operation "%" gives a wrong result

Describe the bug

The operation "%" gives a wrong result

Context

Device: Nexus 5
OS Version: Android 9.0.0
App version: 1.0.06

How to reproduce

1.Lauch Simple-Calculator
2.Press button 2
3.Press button %
4.Press button 2
5.Press button =

Actual behavior

The result is 0.0008.
The formula is 2%2%

Expected behavior

The result should be 0.04.
The formula should be like 2%*2 or sth else.

Confusing behaviour after calculating a square root

1. Input e.g. 9
2. Press square root button
3. Result pops up
4. Input any digit
5. Press square root button
6. Square root of 3 displayed

I'm unsure whether this is a bug, but such behaviour may seem strange for some users.

Incorrect answer when using high exponent function

When using exponent function, if the factor is too high, calculator gives result as zero.
Why not undefined or shortened/approximate answer eg 555*E60 ?

Try solving 9^999

correct characters on buttons

To display the butttons, you use ASCII hyphen "-" for minus and ASCII asterisk "*" for times.

Much better would be the Unicode minus operator "−" and times "×", respectively.

I think this would amount to a change in two characters to the file activity_main.xml.

Rewrite Calculator in Kotlin

@tibbi once you mentioned you wanted to see Calculator written in Kotlin. So there's an issue.

Fix percentage calculations

Like 100 % 20

App doesn't start after changing the theme

• Install app from fdroid
• Change theme to black and white
• Exit
• Try to launch it again

App doesn't start!

Adding feature to the app

I have several features that I wish to add to this app, which is

1. To be able to see history
2. To add more equation function, such as Sin() Cos() Tan()
3. To be able to put the current equation on hold for later use
4. To be able to export history into a .txt file for sharing with others.

That's all the features I wish to add, Thank you.

Add guidelines for contributing in the readme

Static Context field leads to memory leak

Simple-Calculator/app/src/main/kotlin/com/simplemobiletools/calculator/helpers/MyWidgetProvider.kt

Line 27 in 3a5d4e9

private var mContext: Context? = null

The other static fields seem to contain references to Context too. Why to keep them static?

0^0 returns 0

Should be invalid expression, contrary to what Google's, Microsoft's and 95% other calculators say.

scientific calculator ui is there but there is no code found to execute that ui if its there then also its not working