It depends on two things: your SheetCourier plan and your email provider.
Your SheetCourier plan #
- Free: 100 real emails per computer, with every feature. Tests to yourself are unlimited and never count.
- With a license: SheetCourier itself has no limit.
Your email provider #
Every provider allows only so many emails a day from one account: about 500 for a normal Gmail account, about 2,000 for Google Workspace, about 300 for Outlook.com, and more for most work accounts. SheetCourier stays at or a little below that limit and offers to send the rest the next day. The full table is in Daily sending limits explained.
How long does it take? #
At the normal pace of one email every 4 to 8 seconds, 100 people take about 10 minutes. You can use the rest of SheetCourier while it sends; keep the app open until the mailing is done.