67Leads › Free tools › Cold email campaign calculator
To book 10 meetings at a 3.4% reply rate you need about 1,322 leads and 3,966 emails, which is 7 inboxes sending 30/day for 20 days.
Worked example with the default inputs. Change any number and press Calculate.
meetings booked = 10 / 80% = 13 replies = 13 / 30% interested = 44 leads reached = 44 / 3.4% reply = 1,295 leads to buy = 1,295 / (1 - 2% bounce) = 1,322 emails = 1,322 x 3 steps = 3,966 inboxes = 3,966 / 20 days / 30 per inbox = 7 domains = 7 / 3 inboxes per domain = 3
Updated 5 Nov 2026. Free, no account.
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Work backwards from meetings held: divide by the show rate to get meetings booked, by the share of replies that are interested to get replies (each interested reply is assumed to book one meeting), by the reply rate to get people reached, and by one minus the bounce rate to get the leads to buy. Emails are leads times sequence steps. Inboxes are emails spread over the sending days at the per-inbox limit. Every step rounds up.
To book 10 meetings at a 3.4% reply rate you need about 1,322 leads and 3,966 emails, which is 7 inboxes sending 30/day for 20 days.
This calculator assumes 30, a common planning figure, not a provider limit. New domains should start far lower: Instantly's 2026 report suggests about 5 to 10 a day, rising over 4 to 6 weeks.
Total emails divided by sending days divided by sends per inbox per day, rounded up. The calculator spreads inboxes over domains at 3 per domain.
Instantly's 2026 benchmark reports a 3.43% average reply rate; other published benchmarks range from under 1% to over 4%. Plan with a conservative figure and replace it with your own after the first campaign.
Type the trade and place in the Market box. The calculator compares your target with the live count of mail-server-verified emails 67Leads holds for it.
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