How many articles can I process at once with bulk actions?

Up to 50 articles at a time. Once 50 are selected, further clicks add nothing and the counter in the bar shakes, and a Shift+click range stops at 50. Run the action, clear the selection and select the next batch.

Work in batches

1. Click the Bulk actions button in the header, or Enable select mode in its ⋯ menu in Column view, and tick up to 50 articles. Shift+click selects a range.
2. Click the action in the bar, for example Add tags or Mark as read.
3. Press Esc once to clear the selection and stay in select mode.
4. Tick the next 50 and repeat. Press Esc again, or click the X in the bar, when you're done.

When 50 isn't enough

Only the articles already loaded in the list can be selected, so scroll down to load more before you select. To mark a whole feed or folder read, use Mark all as read instead of selecting its articles. For articles that haven't arrived yet, a rule acts on every match without any selecting, and a filter removes the ones you don't want to see.

What are bulk actions? gives the overview, How do I use bulk actions? the steps and What can I do with bulk actions? the buttons. How do I tag an article? and How do I create an Intelligence report? cover the two actions that open a dialog of their own.

Bulk actions are a Pro feature: a Free account can select articles, but the buttons are disabled and the bar shows "Bulk actions are only available to Pro users." with Upgrade now.