The count, before the interpretation
A q1 journal list is only as honest as the directory underneath it, so here is ours with the arithmetic exposed. ConfJournal's directory holds 329 venues: 188 journals and 141 conferences. Of the 188 journals, 172 carry a Q1 rank, the top quartile of their field, and the remaining 16 sit in Q2. No journal in the directory ranks below Q2, which tells you something about how the directory was built: it is a curated target list for researchers choosing where to submit, not a census of everything published.
What Q1 actually certifies
A quartile is a rank within a field, not a quality grade in the abstract. Ranking services order a field's journals by citation influence and cut the list into four: the top 25 percent are Q1. A Q1 journal in a small field can carry a modest impact factor, and a Q2 journal in a giant field can be heavily cited; the quartile says where the journal stands among its direct peers. That is why the same title can be Q1 in one subject category and Q2 in another, and why serious list pages, including SCImago's own master table of more than 32,000 journals, always show the category beside the quartile.
Why the conferences in the directory use different letters
Conferences do not take quartiles in this directory; they take tiers: 57 venues at A*, 66 at A, 13 at B and 3 at C, a ladder borrowed from conference-ranking practice where citation quartiles fit poorly. Mixing the two ladders into one league table is the most common error in venue guides. Kept apart, each ladder answers its own question: among journals, which quartile; among conferences, which tier.
Check a venue before you commit a manuscript
The Submission Odds Checker runs any venue in the directory against your own read of your paper, and the directory itself is searchable by field. A quartile narrows the list; it does not make the decision, and any list that pretends otherwise is selling something.