Two numbers

J-index is the greatest number N such that you have N posts with at least N upvotes each. It is the h-index applied to your posts instead of your papers.

J10-index is simply the count of your posts with at least 10 upvotes — the i10-index analog, a plain measure of how many posts cleared a meaningful bar.

A worked example

Say your five most-upvoted posts have 12, 9, 7, 4, and 2 upvotes. Your J-index is 4: you have four posts with at least four upvotes each. You don’t reach 5, because that would need five posts at five-or-more upvotes — and your fifth post only has two.

One viral post can’t carry your J-index; a steady record of posts that colleagues found worth upvoting can. That’s the point.

What counts, and what doesn’t

Only upvotes feed the J-index — the way citations feed the h-index. There is no recency decay and no per-post cap. An upvote is one signal per person per post, and you can’t upvote yourself.

Reposts, quote-posts, comments, bookmarks, and follower counts are social-distribution signals — they help your work travel, but they do not change your J-index. We kept the formula to the one thing scientists already read as a measure of durable contribution.

When it appears

A J-index is held back until a profile is at least 30 days old and has at least five published posts. Before that, a single early upvote would swing the number wildly, so we show nothing rather than something misleading.