🗂️ Build a Beginner-Friendly File Renamer GUI in Python (Tkinter)

Renaming lots of files manually is tedious. In this tutorial, we’ll build a desktop GUI app in Python using Tkinter that lets users:

Select a folder

Preview file renaming changes

Add prefixes/suffixes

Find & replace text in filenames

Rename files safely

Undo the last rename operation

No prior Tkinter experience required 🚀

🧰 Step 1: Import the Required Modules

Let’s start by importing everything we need.

import tkinter as tk
from tkinter import filedialog, messagebox
import os
from copy import deepcopy

Why these imports?

tkinter → builds the GUI

filedialog → opens a folder picker

messagebox → shows popups (errors, confirmations)

os → works with files and paths

deepcopy → safely store original filenames for undo

🏗️ Step 2: Create the Main Application Class

We’ll wrap the entire app inside a class to keep things organized.

class FileRenamerApp:
    def __init__(self, root):
        self.root = root
        self.root.title("File Renamer")
        self.root.geometry("700x700")
        self.root.configure(bg="#1f2f3a")
        self.root.resizable(False, False)

What’s happening here?

root is the main Tkinter window

We set:

window title

fixed size

background color

disable resizing

🧠 Step 3: Store App State (Important!)

We’ll keep track of files and renaming history.

        self.folder_path = ""
        self.files = []
        self.original_files = []
        self.preview_files = []

Why do we need this?

files → current files in the folder

original_files → used for undo

preview_files → shows renamed filenames before applying

🎨 Step 4: Build the User Interface Skeleton

At the end of init, we call a method that builds the UI.

        self.create_ui()

Let’s define that next.

🖼️ Step 5: App Title

def create_ui(self):
    tk.Label(
        self.root,
        text="File Renamer",
        font=("Helvetica", 28, "bold"),
        bg="#1f2f3a",
        fg="#ffffff"
    ).pack(pady=20)

This adds a big title at the top of the window.

📁 Step 6: Folder Selection Section
Folder input + Browse button

folder_frame = tk.Frame(self.root, bg="#1f2f3a")
folder_frame.pack(pady=10, fill="x", padx=20)

tk.Label(
    folder_frame,
    text="Select Folder:",
    font=("Helvetica", 12),
    bg="#1f2f3a",
    fg="#bdc3c7"
).pack(anchor="w")

self.folder_entry = tk.Entry(
    folder_frame,
    font=("Helvetica", 14),
    width=50
)
self.folder_entry.pack(side="left", pady=5)

tk.Button(
    folder_frame,
    text="Browse",
    command=self.browse_folder
).pack(side="left", padx=5)

What this does

Displays the selected folder path

Opens a folder picker when clicking Browse

🔍 Step 7: Prefix, Suffix, Find & Replace Inputs

options_frame = tk.Frame(self.root, bg="#1f2f3a")
options_frame.pack(pady=10, fill="x", padx=20)

Prefix & Suffix

tk.Label(options_frame, text="Prefix:").grid(row=0, column=0)
self.prefix_entry = tk.Entry(options_frame, width=25)
self.prefix_entry.grid(row=0, column=1)

tk.Label(options_frame, text="Suffix:").grid(row=0, column=2)
self.suffix_entry = tk.Entry(options_frame, width=25)
self.suffix_entry.grid(row=0, column=3)

Find & Replace

tk.Label(options_frame, text="Find:").grid(row=1, column=0)
self.find_entry = tk.Entry(options_frame, width=25)
self.find_entry.grid(row=1, column=1)

tk.Label(options_frame, text="Replace:").grid(row=1, column=2)
self.replace_entry = tk.Entry(options_frame, width=25)
self.replace_entry.grid(row=1, column=3)

These inputs control how filenames will be transformed.

👀 Step 8: Preview Listbox

Before renaming files, users should see what will happen.

self.preview_listbox = tk.Listbox(
    self.root,
    font=("Helvetica", 12),
    bg="#2c3e50",
    fg="white"
)
self.preview_listbox.pack(fill="both", expand=True, padx=20, pady=10)

This shows:

Original filenames

Previewed renamed filenames

🧪 Step 9: Preview Changes Logic

def preview_changes(self):
    prefix = self.prefix_entry.get()
    suffix = self.suffix_entry.get()
    find_text = self.find_entry.get()
    replace_text = self.replace_entry.get()

    self.preview_files = []

    for filename in self.files:
        new_name = filename

        if find_text:
            new_name = new_name.replace(find_text, replace_text)

        if prefix:
            new_name = prefix + new_name

        if suffix:
            name, ext = os.path.splitext(new_name)
            new_name = name + suffix + ext

        self.preview_files.append(new_name)

    self.update_preview_list(self.preview_files)

Key idea

👉 Nothing is renamed yet.
We only show a preview so users can double-check.

✏️ Step 10: Rename Files Safely

def rename_files(self):
    if not self.preview_files:
        messagebox.showerror("Error", "Preview changes first!")
        return

Confirmation dialog
confirm = messagebox.askyesno(
    "Confirm",
    "Are you sure you want to rename all files?"
)

Perform renaming + save undo history

self.last_rename = []

for old, new in zip(self.original_files, self.preview_files):
    if old != new:
        os.rename(
            os.path.join(self.folder_path, old),
            os.path.join(self.folder_path, new)
        )
        self.last_rename.append((new, old))

↩️ Step 11: Undo Last Rename

def undo_rename(self):
    if not self.last_rename:
        messagebox.showerror("Error", "Nothing to undo.")
        return

for current, original in self.last_rename:
    os.rename(
        os.path.join(self.folder_path, current),
        os.path.join(self.folder_path, original)
    )

This restores filenames exactly as they were before.

▶️ Step 12: Run the App

if __name__ == "__main__":
    root = tk.Tk()
    app = FileRenamerApp(root)
    root.mainloop()

This launches the GUI window.

🎉 Final Thoughts

You just built a fully functional desktop file renamer with:

GUI layout

File system access

Preview safety

Undo support

Ideas to extend it

Numbered filenames

Regex support

File type filters

Dark/light mode toggle