Couple of posts:

• “We’re honored to report that over 11 million showed up for today’s No Kings protest”
• “A lot of people have questioned our No Kings crowd estimates…”
• 3.5% rule

The 3.5% rule is more of an observation than a rule. It’s hopeful, but little more than that.

I couldn’t quickly find a citation for 13 million, but the first post does indicate counts are still coming in.