Not giving a total

So, I'm working on a GUI using pysimplegui the project is a compound interest calculator. So, when I hit the complete button, it should give me a total after so many years, but I just get 0.00.

# make a gui interest calc
import PySimpleGUI as sg


def main():
    principle = 0
    rate = 0
    time = 0

    # using 3 vars so the user can fill in to get
    # the total of time and rate of interest

    principleInputText = sg.Text("Enter principle amount: ")
    principleInput = sg.InputText(key="principles")

    rateInputText = sg.Text("Enter interest rate: ")
    rateInput = sg.InputText(key='rates')

    timeInputText = sg.Text("Enter time in years: ")
    timeInput = sg.InputText(key='times')

    complete_button = sg.Button("Complete")
    output_label = sg.Text(key='output', text_color="black")

    layout = [[principleInputText, principleInput],
              [rateInputText, rateInput],
              [timeInputText, timeInput],
              [complete_button],
              [output_label]]

    # title of project
    window = sg.Window(title="Compound Interest Calculator",
                       layout=layout)
    while True:
        event, values = window.read()
        print(event, values)
        match event:
            case 'principles':
                while principle <= 0:
                    principle = float(principleInput)
                    if principle <= 0:
                        print("principle cant be less or equal to 0")

            case 'rates':
                while rate <= 0:
                    rate = float(rateInput)
                    if rate <= 0:
                        print("Interest rate cant be less or equal to 0")
            case 'times':
                while time <= 0:
                    time = int(timeInput)
                    if time <= 0:
                        print("Time cant be less or equal to 0")

            case 'Complete':
                total = principle * pow((1 + rate / 100), time)
                print(total)
                window['output'].update(value=f'Balance after {time} year/s: ${total: .2f}')
        # end program if user closes window
        if event == "OK" or event == sg.WIN_CLOSED:
            break


if __name__ == "__main__":
    main()

I've tried to put the floats as float(input(var name)), but I still get the same result.

Need option enable_events=True for all your Input elements, so you can get event when input, and the values for those elements won't be the initial value, 0.

Another issue is that you have to use values[key] to get the content of input elements before you convert them into float.

Example Code

import PySimpleGUI as sg

def convert(string):
    try:
        value = float(string)
        if value <= 0:
            result, value = False, None
        else:
            result = True
    except ValueError:
        result, value = False, None
    return result, value

items = [
    ["Amount", "Principle amount"],
    ["Rate", "Interest rate"],
    ["Times", "Time in years" ],
]
keys = [key for key, entry in items]

font = ("Courier New", 16)
sg.theme("DarkBlue")
sg.set_options(font=font)

layout = [
    [sg.Text(entry), sg.Push(), sg.Input(size=30, key=key)] for key, entry in items] + [
    [sg.Text("", expand_x=True, justification="center", key="Output")],
    [sg.Push(), sg.Button("Submit"),sg.Push()],
]
window = sg.Window(title="Compound Interest Calculator", layout=layout)

while True:

    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break

    elif event == "Submit":
        data = []
        for key in keys:
            ok, value = convert(values[key])
            if not ok:
                sg.popup(f"The value of {key} entered is wrong !", button_justification="center")
                break
            data.append(value)
        else:
            principle, rate, time = data
            total = principle * pow((1 + rate / 100), time)
            window['Output'].update(f'Balance after {time} year/s: ${total: .2f}')

window.close()