Python PyQt5 GUI Loan Calculator Desktop App Using Annual Interest, Years and Principal Amount Full Project For Beginners
Welcome folks today in this blog post we will be building a loan calculator
gui app inside pyqt5
in python. All the full source code of the application is shown below.
Get Started
In order to get started you need to install the following library using the pip
command as shown below
pip install pyqt5
After installing this library make an app.py
file and copy paste the following code
app.py
# importing required libraries
from PyQt5.QtWidgets import *
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys
class Window(QMainWindow):
# constructor
def __init__(self):
super().__init__()
# setting title
self.setWindowTitle("Python ")
# width of window
self.w_width = 400
# height of window
self.w_height = 500
# setting geometry
self.setGeometry(100, 100, self.w_width, self.w_height)
# calling method
self.UiComponents()
# showing all the widgets
self.show()
# method for adding components
def UiComponents(self):
# creating head label
head = QLabel("Loan Calculator", self)
# setting geometry to the head
head.setGeometry(0, 10, 400, 60)
# font
font = QFont('Times', 15)
font.setBold(True)
font.setItalic(True)
font.setUnderline(True)
# setting font to the head
head.setFont(font)
# setting alignment of the head
head.setAlignment(Qt.AlignCenter)
# setting color effect to the head
color = QGraphicsColorizeEffect(self)
color.setColor(Qt.darkCyan)
head.setGraphicsEffect(color)
# creating a interest label
i_label = QLabel("Annual Interest", self)
# setting properties to the interest label
i_label.setAlignment(Qt.AlignCenter)
i_label.setGeometry(20, 100, 170, 40)
i_label.setStyleSheet("QLabel"
"{"
"border : 2px solid black;"
"background : rgba(70, 70, 70, 35);"
"}")
i_label.setFont(QFont('Times', 9))
# creating a QLineEdit object to get the interest
self.rate = QLineEdit(self)
# accepting only number as input
onlyInt = QIntValidator()
self.rate.setValidator(onlyInt)
# setting properties to the rate line edit
self.rate.setGeometry(200, 100, 180, 40)
self.rate.setAlignment(Qt.AlignCenter)
self.rate.setFont(QFont('Times', 9))
# creating a number of years label
n_label = QLabel("Years ", self)
# setting properties to the years label
n_label.setAlignment(Qt.AlignCenter)
n_label.setGeometry(20, 150, 170, 40)
n_label.setStyleSheet("QLabel"
"{"
"border : 2px solid black;"
"background : rgba(70, 70, 70, 35);"
"}")
n_label.setFont(QFont('Times', 9))
# creating a QLineEdit object to get the years
self.years = QLineEdit(self)
# accepting only number as input
onlyInt = QIntValidator()
self.years.setValidator(onlyInt)
# setting properties to the rate line edit
self.years.setGeometry(200, 150, 180, 40)
self.years.setAlignment(Qt.AlignCenter)
self.years.setFont(QFont('Times', 9))
# creating a loan amount label
a_label = QLabel("Amount", self)
# setting properties to the amount label
a_label.setAlignment(Qt.AlignCenter)
a_label.setGeometry(20, 200, 170, 40)
a_label.setStyleSheet("QLabel"
"{"
"border : 2px solid black;"
"background : rgba(70, 70, 70, 35);"
"}")
a_label.setFont(QFont('Times', 9))
# creating a QLineEdit object to get the amount
self.amount = QLineEdit(self)
# accepting only number as input
onlyInt = QIntValidator()
self.amount.setValidator(onlyInt)
# setting properties to the rate line edit
self.amount.setGeometry(200, 200, 180, 40)
self.amount.setAlignment(Qt.AlignCenter)
self.amount.setFont(QFont('Times', 9))
# creating a push button
calculate = QPushButton("Compute Payment", self)
# setting geometry to the push button
calculate.setGeometry(125, 270, 150, 40)
# adding action to the calculate button
calculate.clicked.connect(self.calculate_action)
# creating a label to show monthly payment
self.m_payment = QLabel(self)
# setting properties to m payment label
self.m_payment.setAlignment(Qt.AlignCenter)
self.m_payment.setGeometry(50, 340, 300, 60)
self.m_payment.setStyleSheet("QLabel"
"{"
"border : 3px solid black;"
"background : white;"
"}")
self.m_payment.setFont(QFont('Arial', 11))
# creating a label to show monthly payment
self.y_payment = QLabel(self)
# setting properties to y payment label
self.y_payment.setAlignment(Qt.AlignCenter)
self.y_payment.setGeometry(50, 410, 300, 60)
self.y_payment.setStyleSheet("QLabel"
"{"
"border : 3px solid black;"
"background : white;"
"}")
self.y_payment.setFont(QFont('Arial', 11))
# method for calculating monthly
# and annually payments
def calculate_action(self):
# getting annual interest rate
annualInterestRate = self.rate.text()
# if there is no number is entered
if len(annualInterestRate) == 0 or annualInterestRate == '0':
return
# getting number of years
numberOfYears = self.years.text()
# if there is no number is entered
if len(numberOfYears) == 0 or numberOfYears == '0':
return
# getting loan amount
loanAmount = self.amount.text()
# if there is no number is entered
if len(loanAmount) == 0 or loanAmount == '0':
return
# converting text to int
annualInterestRate = int(annualInterestRate)
numberOfYears = int(numberOfYears)
loanAmount = int(loanAmount)
# getting monthly interest rate
monthlyInterestRate = annualInterestRate / 1200
# calculating monthly payemnt
monthlyPayment = loanAmount * monthlyInterestRate / (1 - 1 / (1 + monthlyInterestRate) ** (numberOfYears * 12))
# setting formatting
monthlyPayment = "{:.2f}".format(monthlyPayment)
# setting text to the label
self.m_payment.setText("Monthly Payment : " + str(monthlyPayment))
# getting total payment
totalPayment = float(monthlyPayment) * 12 * numberOfYears
totalPayment = "{:.2f}".format(totalPayment)
# setting text to the label
self.y_payment.setText("Total Payment : " + str(totalPayment))
# create pyqt5 app
App = QApplication(sys.argv)
# create the instance of our Window
window = Window()
# start the app
sys.exit(App.exec())
Now if you execute the above python script by typing the below command as shown below
python app.py