Capacity Calculator
Start with the scale. See what it takes.
Enter the number of mailboxes or daily sends you want to support. TenantCore works backward to show the domains, Microsoft 365 environments, tenant slots, and estimated TenantCore cost needed to support it.
Current target
3,000
sends / day
01 / Plan your scale
What do you want to size for?
Target sends per day
We'll calculate the mailbox, domain, and environment footprint needed to support that volume.
TenantCore plan
Base, Plus, and Complete use the same core capacity model. The plan changes the automation, reporting, and API features—not the number of domains or mailboxes each environment can support.
Planning assumptions
Adjust the density to match your operating model.Mailboxes per domain
Plan between 1 and 3 mailboxes on each domain.
3
Domains per environment
Plan between 1 and 12 domains in each Microsoft 365 environment.
12
Daily limit per mailbox
Estimate capacity using a per-mailbox limit from 1 to 25.
25
02 / Required footprint
How the footprint scales
3,000 sends/day ÷ 25/mailbox = 120 mailboxes
120 mailboxes ÷ 3/domain = 40 domains
40 domains ÷ 12/environment = 4 environments
Estimated TenantCore cost
$34/mo
Plus plan: $29/mo.
4 tenant slots needed. 3 included to start with the plan.
1 additional tenant slot: $5/mo.
Domains, Microsoft 365 licensing, sending tools, and other third-party services are not included.
3 tenant slots to start
Additional tenant slots $5/month each
12 domains in each environment
3 mailboxes per domain
36 mailboxes in each environment
1-25 sends/mailbox/day
This calculator estimates infrastructure capacity and TenantCore subscription cost. It does not predict deliverability, inbox placement, reply rates, or campaign performance.