Currency Converter – Python Project with Source Code

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In this tutorial, we are going to build an exciting python project through which you can convert currencies. For a user interface, we are going to use the tkinter library

Currency Converter in Python

Prerequisites

The currency converter project in python requires you to have basic knowledge of python programming and the pygame library.

• tkinter – For User Interface (UI)
• requests – to get url

To install the tkinter and requests library, type the following code in your terminal:

pip install tkinter
pip install requests

Download Project Code

Before proceeding ahead, please download source code of project: Currency Converter Project Code

Steps to Build the Python Project on Currency Converter

1. Real-time Exchange rates
2. Import required Libraries
3. CurrencyConverter Class
4. UI for CurrencyConverter
5. Main Function

1. Real-time Exchange rates

To get real-time exchange rates, we will use: https://api.exchangerate-api.com/v4/latest/USD

Here, we can see the data in JSON format, with the following details:

Base – USD: It means we have our base currency USD. which means to convert any currency we have to first convert it to USD then from USD, we will convert it in whichever currency we want.

Date and time: It shows the last updated date and time.

Rates: It is the exchange rate of currencies with base currency USD.

2. Import the libraries:

For this project based on Python, we are using the tkinter and requests library. So we need to import the library.

import requests
from tkinter import *
import tkinter as tk
from tkinter import ttk

3. Create the CurrencyConverter class:

Now we will create the CurrencyConverter class which will get the real-time exchange rate and convert the currency and return the converted amount.

3.1. Let’s create the constructor of class.

class RealTimeCurrencyConverter():
    def __init__(self,url):
        self.data= requests.get(url).json()
        self.currencies = self.data['rates']

requests.get(url) load the page in our python program and then .json() will convert the page into the json file. We store it in a data variable.

3.2. Convert() method:

def convert(self, from_currency, to_currency, amount): 
    initial_amount = amount 
    #first convert it into USD if it is not in USD.
    # because our base currency is USD
    if from_currency != 'USD' : 
        amount = amount / self.currencies[from_currency] 
  
    # limiting the precision to 4 decimal places 
    amount = round(amount * self.currencies[to_currency], 4) 
    return amount

This method takes following arguments:

From_currency: currency from which you want to convert.
to _currency: currency in which you want to convert.
Amount: how much amount you want to convert.

And returns the converted amount.

Example:

url = 'https://api.exchangerate-api.com/v4/latest/USD'
converter = RealTimeCurrencyConverter(url)
print(converter.convert('INR','USD',100))

OUTPUT: 1.33

100 Indian rupees = 1.33 US dollars

4. Now let’s create a UI for the currency converter

To Create UI we will create a class CurrencyConverterUI

def __init__(self, converter):
    tk.Tk.__init__(self)
    self.title = 'Currency Converter'
    self.currency_converter = converter

Converter: Currency Converter object which we will use to convert currencies. Above code will create a Frame.

Let’s Create the Converter

self.geometry("500x200")

#Label
self.intro_label = Label(self, text = 'Welcome to Real Time Currency Convertor',  fg = 'blue', relief = tk.RAISED, borderwidth = 3)
self.intro_label.config(font = ('Courier',15,'bold'))

self.date_label = Label(self, text = f"1 Indian Rupee equals = {self.currency_converter.convert('INR','USD',1)} USD \n Date : {self.currency_converter.data['date']}", relief = tk.GROOVE, borderwidth = 5)

self.intro_label.place(x = 10 , y = 5)
self.date_label.place(x = 170, y= 50)

NOTE: This Code part of __init__ method.

First, we set up the frame and add some info in it. After the execution of this part of code, our frame looks like something.

Now let’s create the entry box for the amount and options of currency in the frame. So That users can enter the amount and choose among currencies.

# Entry box
valid = (self.register(self.restrictNumberOnly), '%d', '%P')
# restricNumberOnly function will restrict thes user to enter invavalid number in Amount field. We will define it later in code
self.amount_field = Entry(self,bd = 3, relief = tk.RIDGE, justify = tk.CENTER,validate='key', validatecommand=valid)
self.converted_amount_field_label = Label(self, text = '', fg = 'black', bg = 'white', relief = tk.RIDGE, justify = tk.CENTER, width = 17, borderwidth = 3)
 
# dropdown
self.from_currency_variable = StringVar(self)
self.from_currency_variable.set("INR") # default value
self.to_currency_variable = StringVar(self)
self.to_currency_variable.set("USD") # default value
 
font = ("Courier", 12, "bold")
self.option_add('*TCombobox*Listbox.font', font)
self.from_currency_dropdown = ttk.Combobox(self, textvariable=self.from_currency_variable,values=list(self.currency_converter.currencies.keys()), font = font, state = 'readonly', width = 12, justify = tk.CENTER)
self.to_currency_dropdown = ttk.Combobox(self, textvariable=self.to_currency_variable,values=list(self.currency_converter.currencies.keys()), font = font, state = 'readonly', width = 12, justify = tk.CENTER)
 
# placing
self.from_currency_dropdown.place(x = 30, y= 120)
self.amount_field.place(x = 36, y = 150)
self.to_currency_dropdown.place(x = 340, y= 120)
#self.converted_amount_field.place(x = 346, y = 150)
self.converted_amount_field_label.place(x = 346, y = 150)

NOTE: This code is part of __init__

After the successful Execution of code till now. We will get below screen:

Now Let’s add the CONVERT button which will call the perform function.

 # Convert button
self.convert_button = Button(self, text = "Convert", fg = "black", command = self.perform) 
self.convert_button.config(font=('Courier', 10, 'bold'))
self.convert_button.place(x = 225, y = 135)

Command = self.perform – It means on click it will call perform().

perform() method:

The perform method will take the user input and convert the amount into the desired currency and display it on the converted_amount entry box.

def perform(self,):
        amount = float(self.amount_field.get())
        from_curr = self.from_currency_variable.get()
        to_curr = self.to_currency_variable.get()
 
        converted_amount= self.currency_converter.convert(from_curr,to_curr,amount)
        converted_amount = round(converted_amount, 2)
     
        self.converted_amount_field_label.config(text = str(converted_amount))

NOTE: this function is a part of App class.

RestrictNumberOnly() method:

Now let’s create a restriction in our entry box. So that user can enter only a number in Amount Field. We have discussed earlier that this will be done by our RrestricNumberOnly method.

def restrictNumberOnly(self, action, string):
        regex = re.compile(r"[0-9,]*?(\.)?[0-9,]*$")
        result = regex.match(string)
        return (string == "" or (string.count('.') <= 1 and result is not None))

NOTE: This function is a part of App class.

5. Let’s create the main function.

First, we will create the Converter. Second, Create the UI for Converter

if __name__ == '__main__':
    url = 'https://api.exchangerate-api.com/v4/latest/USD'
    converter = RealTimeCurrencyConverter(url)
 
    App(converter)
    mainloop()

Summary

In this article, we worked on the Python project to build a Currency Converter.

I hope you learned new things and enjoyed building this interesting Python project. Share the article on social media with your friends and colleagues.