Cold email leads needed calculator: how many leads your domains can use each month
In short: Two directions: domains, inboxes per domain, emails per inbox and sequence steps to the new leads you need each day, week and month (grossed up for the share verification removes); or a list size and a deadline to the inboxes and domains it needs. Limit: It assumes every lead receives every step. Replies and bounces stop a sequence early, which leaves a little more room than shown.
Divide what your inboxes can send in a day by the number of emails in your sequence: that is how many new leads you can start each day. Ten domains with three inboxes at 30 a day send 900 emails, so a three-step sequence takes 300 new leads a day, about 6,500 a month on weekdays. The calculator also works backwards from a list.
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. See pricing
A placeholder: replace it with what verification removed from a sample of your source.
- Emails a day
- 900
- New leads a day
- 300
- New leads a month
- 6,500
- Leads to source a month
- 8,125
30 inboxes send 900 emails a day. With 3 emails per lead, that starts 300 new leads a day, 1,500 a week and about 6,500 a month. If verification removes 20%, source 8,125 leads a month to keep the inboxes full.
New leads a month = FLOOR(domains × inboxes × emails per inbox ÷ steps) × sending days × 52 ÷ 12. Leads to source = that ÷ (1 − invalid share).
Next step
6,500 leads a month only fill the inboxes if they're real.
Every address that bounces costs a send from a young domain. Check the month's leads before they go into the sequencer.
No list right now? This tool stays free, no account, so bookmark it for next time. Ctrl+D (⌘+D on a Mac)
Ready to verify now? Verify the list
Sample result
10 domains × 3 inboxes × 30 a day, with 3 emails per lead, need 6,500 new leads a month.
- New leads a month
- 6,500
- Emails a day
- 900
- Leads to source
- 8,125
What this means for you
Source 8,125 if verification removes 20%, so the inboxes never run dry.
- Domains to leads a month
- List size to domains needed
- Grossed up for verification
- Formula shown
- Cold email
- Capacity
- Leads
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
You know how many leads you need. Now make sure they're real.
- Export the leads you plan to load this month as a CSV.
- Upload or paste it at /verify. The first 100 email checks are free with a Google sign-in, no card.
- For every list after that, Pro includes unlimited email verification. Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.
How many leads do I need for cold email?
- Pick a direction: I have domains (how many leads do they need) or I have a list (how many domains does it need).
- Enter your sending domains, inboxes per domain, cold emails per inbox a day, sending days per week and how many emails are in the sequence.
- Enter the share of addresses your verification removes. Use your own figure; verify a sample of the list to measure it.
- Read the new leads a day, week and month, and the leads to source before verification. Copy the formula if you want it in a spreadsheet.
Example
- You enter
- 10 sending domains, 3 inboxes per domain, 30 cold emails per inbox a day, 5 sending days a week, a 3-email sequence and 20% removed by verification.
- You get
- 30 inboxes send 900 emails a day, which starts 300 new leads a day, 1,500 a week and 6,500 a month. Sourcing 8,125 leads a month leaves 6,500 after verification. Backwards, a 10,000-lead list finished in 4 weeks needs 1,200 emails a day: 40 inboxes on 14 domains.
- Limits
- Runs in your browser as you type; nothing is sent.
How do you calculate how many leads cold email needs?
New leads a day = (domains × inboxes per domain × emails per inbox a day) ÷ emails in the sequence. Every lead gets every step, so a day's sending room is shared by first emails and follow-ups; once a campaign is running, the mix settles at one new lead for every steps emails sent. Multiply by sending days per week for a week, and by 52 ÷ 12 for a month.
In a spreadsheet with domains in A2, inboxes per domain in B2, emails per inbox in C2, steps in D2 and sending days in E2: =FLOOR(A2*B2*C2/D2,1)*E2*52/12 gives new leads a month. Divide by (1 - invalid share) for how many to source before verification.
How many domains do I need for my lead list?
Work backwards: total emails = sendable leads × steps; daily sends = total emails ÷ sending days before your deadline; inboxes = daily sends ÷ emails per inbox; domains = inboxes ÷ inboxes per domain, each rounded up. The "I have a list" tab does this. New domains then need warming up before they carry that volume; the warmup calculator plans the ramp and the bulk domain availability checker finds names to register.
Emails per inbox is your decision, not a published limit. Mailbox providers publish no cold-email number; Google's sender guidelines only say to increase volume slowly, and Google Workspace's sending limits (2,000 messages a user a day) are far above sensible cold volume.
Why gross up for verification?
Because addresses you remove before sending don't use up sending room, but you still paid to source them. If verification removes 20% of a list, you need 1,250 raw leads to end up with 1,000 sendable ones. Lists bought or scraped months ago lose more: people change jobs and inboxes close.
The share is your own number. Verify a sample of a new source before you buy in bulk, then use what came back invalid here.
What changes the number of leads you need?
| Change | Effect on new leads a month |
|---|---|
| Add a sending domain | Up in proportion: one more domain's inboxes × emails per inbox, ÷ steps |
| Add a follow-up step | Down: the same room is shared by one more email per lead |
| Raise emails per inbox | Up in proportion, at the cost of more risk per inbox |
| Higher invalid share | Same sendable leads, more raw leads to source |
Who uses this tool, and for what?
- Cold email agencies
- Tell a client how many leads a month their 15 domains need before the first invoice, so list sourcing is budgeted.
- Founders doing outbound
- Check whether a 5,000-lead list is a month or a quarter of sending before you buy more domains.
- Lead list buyers
- Gross up an order for the share that verification will remove, so the sendable count is what you planned.
What can’t this tool tell you?
- It assumes every lead receives every step. Replies and bounces stop a sequence early, which leaves a little more room than shown.
- Emails per inbox and the invalid share are your inputs; the calculator doesn't know what's safe for your domains or how clean a list is.
- Warm-up time isn't included. New domains need weeks of ramping before they send at the volume you enter.
Common questions
- How many leads do I need per month for cold email?
- New leads a day = daily sends ÷ steps in the sequence. With 30 inboxes at 30 emails a day and a three-step sequence, that's 300 a day, about 6,500 a month on a five-day week.
- How many emails per day per inbox for cold email?
- It's your decision; no mailbox provider publishes a cold email limit. Many teams send 20 to 50 per inbox a day. Enter your own figure and the calculator does the rest.
- How many domains do I need for cold email?
- Domains = inboxes ÷ inboxes per domain, and inboxes = daily sends ÷ emails per inbox. Use the I have a list tab to start from a list size and a deadline.
- Do follow-ups count toward the daily limit?
- Yes. Every follow-up is a sent email from the same inbox, which is why more steps means fewer new leads a day.
- Does the calculator send anything?
- No. It runs in your browser with the numbers you type.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.