The page labels supply by pack. Here is a quick check.
The numbers
30 capsules at one a day is 30 days per bottle. Two bottles are 60 capsules (60 days), three are 90, six are 180. The page's supply labels match.
What to watch
This assumes you never miss a day. If you skip some, you will have capsules left after the guarantee window closes. Count capsules on arrival and compare with the label.
Educational note: This guide is general information based on the Quiet Nerves page. Statements have not been evaluated by the Food and Drug Administration. The product is not intended to diagnose, treat, cure or prevent any disease. Individual results vary.