I'm looking for a calculator suitable for large numbers where a letter can be entered instead of a whole bunch of zeros:

• K (Kilo) 000


• 
  M (Mega) 000,000 .............................. Million


• 
  G (Giga) 000,000,000 ....................... Billion


• 
  T (Tera) 000,000,000,000 ............... Trillion


• 
  P (Peta) 000,000,000,000,000 ........ Quadtrillion


• 
  E (Exa) 000,000,000,000,000,000 . Quintrillion

For example $20 trillion dollars / 50 million units would be entered as:

20t / 50m

The result is 400,000 and can be displayed as 400 K.

Is there already a calculator for Ubuntu / Debian for Big Numbers (aka Human Readable format)?

My question is similar to these questions but not a duplicate:

• Add thousand separator to gnome calculator in Ubuntu 18.04


• How to show comma seperation in numbers on ubuntu's calculator?

The letters used such as T for Tera (Trillion) or G for Giga (Billion), etc. come from industry standards. Standards are set by Institute of Electrical and Electronics Engineers (IEEE).

Edit: A few days after original question was posted, this turned into a self-answered question. Original answers though and alternative suggestions are welcome and would likely interest others.

An initial solution only took a few minutes by taking this readily available Python Calculator GUI.

Add a little code

The full script is below but to summarize insert these lines near the top:

self.newtext=self.newtext.replace(' ','')

self.newtext=self.newtext.upper()

self.newtext=self.newtext.replace('K','000')

self.newtext=self.newtext.replace('M','000000')

self.newtext=self.newtext.replace('G','000000000')

self.newtext=self.newtext.replace('T','000000000000')

self.newtext=self.newtext.replace('P','000000000000000')

self.newtext=self.newtext.replace('E','000000000000000000')

Insert these lines near the bottom:

  Button(master,text="E",width=3,command=lambda:self.action('E')).grid(row=5, column=0)

  Button(master,text="P",width=3,command=lambda:self.action('P')).grid(row=5, column=1)

  Button(master,text="T",width=3,command=lambda:self.action('T')).grid(row=5, column=2)

  Button(master,text="G",width=3,command=lambda:self.action('G')).grid(row=5, column=3)

  Button(master,text="M",width=3,command=lambda:self.action('M')).grid(row=5, column=4)

  Button(master,text="K",width=3,command=lambda:self.action('K')).grid(row=5, column=5)

Insert these lines in the middle:

 def convert(self):

    #2**10 = 1024

    power = 1000

    size=self.value

    n = 0

    Dic_powerN = {0: '', 1: 'K', 2: 'M', 3: 'G', 4: 'T', 5: 'P', 6: 'E'}

    while size > power:

        size /=  power

        n += 1

    return size, Dic_powerN[n]

There are a few other cosmetic changes for larger font on HDPI monitor (1920x1080 pixels)

Sample Calculator Window

• This is a pretty standard calculator layout.


• Notice the bottom row of keys we added.


• You can click the keys or simply type in T instead of clicking T button.


• Also notice how we entered 20 t / 50 M to represent 20 Trillion divided by 50 Million.


• The result will be displayed as 400 K
  

Full Python Script

#-*-coding: utf-8-*-

# NAME: calc.py

# CALL: python calc.py

# DATE: December 8, 2018

# DESC: Calculator in E-Exa, P-Peta, T-Tetra, G-Giga, M-Mega and K-Kilo

# NOTE: Requires Tkinter GUI libraries: sudo apt install python-tk



# Majority Credit to: https://www.techinfected.net/2016/02/make-gui-calculator-in-python-windows-linux.html

from Tkinter import *

import tkFont

import math



class calc:

 def getandreplace(self):

  """replace x with * and ÷ with /"""



  self.expression = self.e.get()

  self.newtext=self.expression.replace(self.newdiv,'/')

  self.newtext=self.newtext.replace('x','*')

  self.newtext=self.newtext.replace(' ','')

  self.newtext=self.newtext.upper()

  self.newtext=self.newtext.replace('K','000')

  self.newtext=self.newtext.replace('M','000000')

  self.newtext=self.newtext.replace('G','000000000')

  self.newtext=self.newtext.replace('T','000000000000')

  self.newtext=self.newtext.replace('P','000000000000000')

  self.newtext=self.newtext.replace('E','000000000000000000')



 def equals(self):

  """when the equal button is pressed"""



  self.getandreplace()

  try: 

   self.value= eval(self.newtext) #evaluate the expression using the eval function

  except SyntaxError or NameErrror:

   self.e.delete(0,END)

   self.e.insert(0,'Invalid Input!')

  else:

   self.e.delete(0,END)

   self.value= self.convert()  # Give result in K, M, G, T, P or E

   self.e.insert(0,self.value)



 def convert(self):

    #2**10 = 1024

    power = 1000

    size=self.value

    n = 0

    Dic_powerN = {0: '', 1: 'K', 2: 'M', 3: 'G', 4: 'T', 5: 'P', 6: 'E'}

    while size > power:

        size /=  power

        n += 1

    return size, Dic_powerN[n]



 def squareroot(self):

  """squareroot method"""



  self.getandreplace()

  try: 

   self.value= eval(self.newtext) #evaluate the expression using the eval function

  except SyntaxError or NameErrror:

   self.e.delete(0,END)

   self.e.insert(0,'Invalid Input!')

  else:

   self.sqrtval=math.sqrt(self.value)

   self.e.delete(0,END)

   self.e.insert(0,self.sqrtval)



 def square(self):

  """square method"""



  self.getandreplace()

  try: 

   self.value= eval(self.newtext) #evaluate the expression using the eval function

  except SyntaxError or NameErrror:

   self.e.delete(0,END)

   self.e.insert(0,'Invalid Input!')

  else:

   self.sqval=math.pow(self.value,2)

   self.e.delete(0,END)

   self.e.insert(0,self.sqval)



 def clearall(self): 

  """when clear button is pressed,clears the text input area"""

  self.e.delete(0,END)



 def clear1(self):

  self.txt=self.e.get()[:-1]

  self.e.delete(0,END)

  self.e.insert(0,self.txt)



 def action(self,argi): 

  """pressed button's value is inserted into the end of the text area"""

  self.e.insert(END,argi)



 def __init__(self,master):

  """Constructor method"""

  master.title('Calculator') 

  master.geometry()

  font = "Calibri 13"

  self.e = Entry(master, font = "Calibri 13")

#  self.e = Entry(master)

  self.e.grid(row=0,column=0,columnspan=6,pady=3)

  self.e.focus_set() #Sets focus on the input text area



  self.div='÷'

  self.newdiv=self.div.decode('utf-8')



  #Generating Buttons

#  Button(master,text="=",width=10,command=lambda:self.equals()).grid(row=4, column=4,columnspan=2)

  Button(master,text="=",width=8,command=lambda:self.equals()).grid(row=4, column=4,columnspan=2)

  Button(master,text='AC',width=3,command=lambda:self.clearall()).grid(row=1, column=4)

  Button(master,text='C',width=3,command=lambda:self.clear1()).grid(row=1, column=5)

  Button(master,text="+",width=3,command=lambda:self.action('+')).grid(row=4, column=3)

  Button(master,text="x",width=3,command=lambda:self.action('x')).grid(row=2, column=3)

  Button(master,text="-",width=3,command=lambda:self.action('-')).grid(row=3, column=3)

  Button(master,text="÷",width=3,command=lambda:self.action(self.newdiv)).grid(row=1, column=3) 

  Button(master,text="%",width=3,command=lambda:self.action('%')).grid(row=4, column=2)

  Button(master,text="7",width=3,command=lambda:self.action('7')).grid(row=1, column=0)

  Button(master,text="8",width=3,command=lambda:self.action(8)).grid(row=1, column=1)

  Button(master,text="9",width=3,command=lambda:self.action(9)).grid(row=1, column=2)

  Button(master,text="4",width=3,command=lambda:self.action(4)).grid(row=2, column=0)

  Button(master,text="5",width=3,command=lambda:self.action(5)).grid(row=2, column=1)

  Button(master,text="6",width=3,command=lambda:self.action(6)).grid(row=2, column=2)

  Button(master,text="1",width=3,command=lambda:self.action(1)).grid(row=3, column=0)

  Button(master,text="2",width=3,command=lambda:self.action(2)).grid(row=3, column=1)

  Button(master,text="3",width=3,command=lambda:self.action(3)).grid(row=3, column=2)

  Button(master,text="0",width=3,command=lambda:self.action(0)).grid(row=4, column=0)

  Button(master,text=".",width=3,command=lambda:self.action('.')).grid(row=4, column=1)

  Button(master,text="(",width=3,command=lambda:self.action('(')).grid(row=2, column=4)

  Button(master,text=")",width=3,command=lambda:self.action(')')).grid(row=2, column=5)

  Button(master,text="√",width=3,command=lambda:self.squareroot()).grid(row=3, column=4)

  Button(master,text="x²",width=3,command=lambda:self.square()).grid(row=3, column=5)

  Button(master,text="E",width=3,command=lambda:self.action('E')).grid(row=5, column=0)

  Button(master,text="P",width=3,command=lambda:self.action('P')).grid(row=5, column=1)

  Button(master,text="T",width=3,command=lambda:self.action('T')).grid(row=5, column=2)

  Button(master,text="G",width=3,command=lambda:self.action('G')).grid(row=5, column=3)

  Button(master,text="M",width=3,command=lambda:self.action('M')).grid(row=5, column=4)

  Button(master,text="K",width=3,command=lambda:self.action('K')).grid(row=5, column=5)

#Main

root = Tk()

# Larger font for HDPI screen

default_font = tkFont.nametofont("TkDefaultFont")

default_font.configure(size=11)

obj=calc(root) #object instantiated

root.mainloop()

Many thanks to the author (on first link above) for contributing this code!

Install Tkinter

You need python-tk (Tkinter) installed to use Python GUI Calculator:

sudo apt update

sudo apt install python-tk

For example $20 trillion dollars / 50 million taxpayers would be entered as:

20t / 50m

I will do a frame challenge

The answer here isn't to find software that supports this format, but to learn a standard format used in both calculators, programming languages and math: scientific notation.

You write a number as a base (significand) and an exponent, e.g. 2*10⁵ for 20000. 20 trillions is thus 2*10¹³ - or 20*10¹². This will work on nearly all calculators, allows for compact and exact numbers, independently of language. Billion may for instance mean both 10⁹ and 10¹², depending on culture.

In addition, this allows you to clearly define significant figures, as you may write 7.0*10³ or 7.02*10³, to note the number of known decimals.

In computers this may additionally be written as ney for n*10^y, for instance 5e6 is interpreted as 5*10⁶. This form can be used in for instance octave.