Agency cold email capacity planner: inboxes and domains for clients times leads a month
In short: Enter clients, new leads per client a month, emails per lead, the daily cap per inbox and sending days. Get emails a month, inboxes, domains and inboxes per client, with the math shown. Limit: Every number is your own; the planner does not know any provider's or tool's limits.
Multiply clients by the new leads each gets a month, then by the emails per lead to get emails a month. Divide by sending days for a daily load and by the cap per inbox for inboxes, then by inboxes per domain for domains. This planner does the sums with your numbers, and shows how many clients the inboxes you have already can carry.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. Check your list free nowSee pricing
Steps in the sequence.
The cap you set in your sending tool.
Shows how many clients they carry.
The numbers in the boxes are examples to show how it works. Replace every one with your own; nothing here is a benchmark.
- Leads a month, all clients
- 12,000
- Emails a month
- 36,000
- Inboxes
- 58
- Sending domains
- 20
The math, with your numbers
- Contacts a month = 8 clients x 1,500 = 12,000
- Emails a month = 12,000 x 3 emails per contact = 36,000
- Emails per sending day = 36,000 / 21 days = 1,715 (rounded up)
- Inboxes = 1,715 / 30 per inbox = 58 (rounded up)
- Domains = 58 / 3 inboxes per domain = 20 (rounded up)
- Inboxes per client = 58 / 8 = 7.25
Next step
12,000 leads a month across 8 clients is a lot of lists to check.
Every client's list carries its own dead addresses, and they all bounce from inboxes you pay for. Check each list before it goes into a client's sequence.
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Sample result
Eight clients with 1,500 leads each and 3 emails per lead need 58 inboxes on 20 domains.
- Inboxes
- 58
- Emails a month
- 36,000
- Domains
- 20
What this means for you
Each client's list brings its own dead addresses; check every list before launch.
- Clients times leads
- Inboxes and domains
- Clients your inboxes carry
- Math shown
- Agency
- Capacity
- Calculator
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I plan inbox capacity for a cold email agency?
- Enter the number of clients and the new leads you start for each in a month.
- Enter the emails each lead gets, the emails an inbox sends a day and the sending days in the month.
- Enter how many inboxes you put on one sending domain.
- Optionally enter the inboxes you already have to see how many clients they carry. Read the totals and the math.
Example
- You enter
- 8 clients with 1,500 new leads each a month, 3 emails per lead, 30 emails per inbox a day, 21 sending days and 3 inboxes per domain.
- You get
- 12,000 leads and 36,000 emails a month, 1,715 a sending day, so 58 inboxes on 20 domains: 7.25 inboxes per client.
- Limits
- Runs in your browser; nothing is uploaded. Warm-up and provider limits are not modelled; the cap per inbox is the number you type.
How is the capacity worked out?
Leads a month is clients times leads per client. Emails a month is leads times emails per lead. Dividing by sending days gives the daily load, and dividing that by the cap per inbox, rounded up, gives inboxes. Domains are inboxes divided by inboxes per domain, rounded up.
The page prints each line with your numbers, so you can paste the same sums into a sheet.
Why plan per client?
Most agencies keep each client's sending on separate domains and inboxes so one client's bounce problem does not hurt another's. The inboxes per client figure shows the infrastructure each account needs, which is the number to price against.
The cap per inbox is your own setting. Mailbox providers do not publish a safe number for cold email, so the page uses what you type and does not check it against any limit.
What about the lists?
Leads a month is also the number of addresses you have to check each month, across every client. A list that bounces uses sends and inbox reputation for nothing, and with several clients that adds up.
To turn the capacity into money, use the agency margin calculator. To plan one client's mailboxes in detail, use the cold email volume calculator.
Who uses this tool, and for what?
- Agencies
- Know how many inboxes and domains to buy before signing the next client.
- Agency owners
- Check whether the inboxes you have already can carry a new account.
- Freelancers
- Turn a client's lead target into infrastructure you can cost.
- Ops managers
- Plan the monthly list checks for every client at once.
What can’t this tool tell you?
- Every number is your own; the planner does not know any provider's or tool's limits.
- It assumes every client gets the same volume and every inbox sends the same each day.
- It does not model warm-up, holidays or paused days.
- A plan that fits the cap can still land in spam.
Common questions
- How many inboxes per domain should I use?
- That is your choice and this page does not recommend one. Enter the number you use; the domains figure follows from it.
- Does it include warm-up?
- No. New inboxes send less at first, so plan extra weeks or inboxes while they warm up. The warm-up calculator builds that ramp.
- What is the cap per inbox?
- The most emails one inbox sends a day, first emails and follow-ups together. Use the cap you set in your sending tool.
- Why are inboxes rounded up?
- You cannot run part of an inbox, and rounding down would put the daily load over the cap.
- What does the existing inboxes box do?
- It turns the sum round: inboxes times the cap times sending days, divided by the emails one client needs, rounded down, is the clients those inboxes carry.
- Is my data uploaded?
- No. Everything runs in your browser.
Authentication and capacity are half of deliverability.
The other half is who you send to. Every hard bounce counts against the domain and inboxes you are sending from, and nothing in DNS can tell you which addresses on your list are dead.
- Bulk verification with real SMTP mailbox checks
- Hard bounces removed before a send, not discovered after
- Catch-all, disposable and role detection on every row
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