You can set/update the total of a progress bar tqdm after it starts

• Tagged with python
• Posted 17 May 2025

Update the .total attribute, then call .refresh().

I use the tqdm library to create progress bars in my terminal.

If you know the number of items upfront, you can pass a total to tqdm.tqdm(), for example:

import time
import tqdm

with tqdm.tqdm(total=100) as pbar:
    for _ in tange(100):
        time.sleep(1)

But what if you don’t know the size upfront?

It turns out you can set the total later, and then tqdm will use it when it redraws the progress bar. Here’s a simple example:

import time
import tqdm

with tqdm.tqdm() as pbar:
    for _ in range(5):
        time.sleep(1)
        pbar.update(1)

        pbar.total = 5
        pbar.refresh()

I found this useful in a script where the generator was quite slow (fetching a list of video IDs from a YouTube playlist) and I wanted to start acting on the generator immediately (downloading the videos), but I also wanted a nice progress bar.