Python Currency Converter: Build a Real-Time Tkinter App

Python Currency Converter tutorial: Learn to create a Tkinter GUI app with live exchange rates and instant currency conversion in Python.

The Python Currency Converter is a desktop application built with Tkinter that provides real-time currency conversion using live exchange rates from the Frankfurter API. The program automatically fetches the latest currency list and rate data at startup, ensuring accurate and up-to-date conversions every time the user interacts with the application.

The interface is divided into two main sections.
The left panel handles the conversion process, where users can enter an amount, select the source currency, choose the target currency, and instantly receive the converted value. Error messages are displayed when invalid input is detected, ensuring smooth and reliable operation.

The right panel focuses on displaying exchange rates. Users can pick any currency from the dropdown menu to view how it compares to all other available currencies. The results are shown in a clean, monospaced text table that updates on demand.

The design uses a modern dark theme, with custom colors for backgrounds, labels, buttons, and comboboxes to create a visually appealing interface. The layout dynamically adjusts for better usability, and all widgets integrate seamlessly with the backend conversion logic.

Overall, this application provides fast and accurate currency conversions, clear rate visualization, and a polished user interface — making it a practical and efficient tool for viewing and comparing global currencies in real time.

Difficulty Level:

Beginner

requirement Libraries:

Built-in Python libraries (no installation required)

				
					import tkinter as tk
from tkinter import ttk, messagebox
import requests

# ----------------------------------------------------
# Fetch data once at start
# ----------------------------------------------------
def fetch_data():
    try:
        resp_currencies = requests.get("https://api.frankfurter.app/currencies")
        resp_currencies.raise_for_status()
        currencies_data = resp_currencies.json()

        base_currency = "USD"
        resp_rates = requests.get(f"https://api.frankfurter.app/latest?from={base_currency}")
        resp_rates.raise_for_status()
        rates_data = resp_rates.json()

        return currencies_data, rates_data["rates"], base_currency

    except Exception as e:
        messagebox.showerror("Error", f"Failed to fetch data:\n{e}")
        return None, None, None

currencies, rates, base = fetch_data()
if currencies is None:
    exit()

rates[base] = 1.0
currency_list = list(currencies.keys())

# ----------------------------------------------------
# Convert Logic
# ----------------------------------------------------
def convert_local():
    try:
        amount = float(entry_amount.get())
    except:
        messagebox.showerror("Error", "Please enter a valid amount")
        return

    from_curr = cb_from.get()
    to_curr = cb_to.get()

    result = amount * (rates[to_curr] / rates[from_curr])
    lbl_conv_result.config(text=f"{amount} {from_curr} = {result:.4f} {to_curr}")

# ----------------------------------------------------
# Show rates table
# ----------------------------------------------------
def show_rates():
    selected = cb_view.get()
    txt_rates.delete("1.0", tk.END)

    for curr, value in rates.items():
        result = value / rates[selected]
        txt_rates.insert(tk.END, f"{selected} → {curr}   :   {result:.6f}\n")

# ----------------------------------------------------
# GUI (Dark Theme)
# ----------------------------------------------------
root = tk.Tk()
root.title("Currency Converter")
root.geometry("800x500")
root.resizable(True, True)
root.configure(bg="#1e1e1e")

fg_text = "#ffffff"
accent = "#4cc9f0"
btn_color = "#3a86ff"
frame_bg = "#2b2b2b"

style = ttk.Style()
style.theme_use("clam")

style.configure("TCombobox",
                fieldbackground="#3a3a3a",
                background="#3a3a3a",
                foreground="white")

# --------------- LEFT SIDEBAR --------------
left_frame = tk.Frame(root, width=250, padx=15, pady=15, bg=frame_bg, relief="groove", borderwidth=2)
left_frame.pack(side="left", fill="y")

lbl_title = tk.Label(left_frame, text="Convert Currency", font=("Arial", 14, "bold"), fg=accent, bg=frame_bg)
lbl_title.pack(pady=10)

tk.Label(left_frame, text="Amount:", fg=fg_text, bg=frame_bg).pack(anchor="w")
entry_amount = tk.Entry(left_frame, bg="#3a3a3a", fg="white", insertbackground="white")
entry_amount.pack(fill="x", pady=5)

tk.Label(left_frame, text="From:", fg=fg_text, bg=frame_bg).pack(anchor="w")
cb_from = ttk.Combobox(left_frame, values=currency_list)
cb_from.pack(fill="x", pady=5)
cb_from.current(0)

tk.Label(left_frame, text="To:", fg=fg_text, bg=frame_bg).pack(anchor="w")
cb_to = ttk.Combobox(left_frame, values=currency_list)
cb_to.pack(fill="x", pady=5)
cb_to.current(1)

btn_convert = tk.Button(left_frame, text="Convert", command=convert_local,
                        bg=btn_color, fg="white", activebackground="#4cc9f0")
btn_convert.pack(pady=10)

lbl_conv_result = tk.Label(left_frame, text="", font=("Arial", 11, "bold"), fg=accent, bg=frame_bg)
lbl_conv_result.pack(pady=10)

# ------------- RIGHT CONTENT --------------
right_frame = tk.Frame(root, padx=20, pady=20, bg="#1e1e1e")
right_frame.pack(side="right", fill="both", expand=True)

lbl_view = tk.Label(right_frame, text="View Exchange Rates", font=("Arial", 14, "bold"),
                    fg=accent, bg="#1e1e1e")
lbl_view.pack(pady=10)

cb_view = ttk.Combobox(right_frame, values=currency_list)
cb_view.pack(pady=5, fill="x")
cb_view.current(0)

btn_view = tk.Button(right_frame, text="Show Rates", command=show_rates,
                     bg=btn_color, fg="white", activebackground="#4cc9f0")
btn_view.pack(pady=10)

txt_rates = tk.Text(right_frame, width=50, height=20, font=("Courier", 10),
                    bg="#2b2b2b", fg="white", insertbackground="white")
txt_rates.pack(fill="both", expand=True)

root.mainloop()