Keep your bounce rate under 3%. Verify your email list with catch-all email verifier Giggal.ai
Enter how many cold emails you want to send per day. The calculator works out the inboxes, the domains, the monthly cost and how long the warm-up takes, using safe sending limits for Google Workspace and Microsoft 365.
You need
34
inboxes
7
domains
1,000 emails a day ÷ 30 per inbox = 34 inboxes34 inboxes ÷ 5 per domain = 7 domains
Ramp-up plan
Week 1–2: warm-up only. Week 3: about 340 a day. Week 4 onwards: up to 1,020 a day.
Sending limits
Google and Microsoft allow far more than a cold inbox should ever send. What keeps you in the inbox is low, steady volume per mailbox.
20 a day
Cautious
New domains, strict audiences, or recovering reputation.
30 a day
Typical
Warmed-up inboxes on healthy domains. The calculator’s default.
40 a day
Upper end
Well-established inboxes with strong reply rates.
Google Workspace hard limit
2,000
messages a day per user →
Microsoft 365 hard limit
10,000
recipients a day per mailbox →
Gmail spam-rate ceiling
0.3%
ideally under 0.1%
Quick reference
At 30 cold emails per inbox per day and five inboxes per domain. Monthly cost is PureMail's inbox price with setup included; domains are extra at your registrar.
| Cold emails per day | Inboxes | Domains | Per month |
|---|---|---|---|
| 100 | 10 | 2 | $33.00 |
| 300 | 10 | 2 | $33.00 |
| 500 | 17 | 4 | $56.10 |
| 1,000 | 34 | 7 | $105.40 |
| 2,500 | 84 | 17 | $260.40 |
| 5,000 | 167 | 34 | $484.30 |
| 10,000 | 334 | 67 | $968.60 |
The smallest order is 10 inboxes, so the first rows round up. Prices: $3.30 per inbox under 30, $3.10 at 30–100, $2.90 from 101. See pricing.
Google or Microsoft
Send to Gmail users from Google Workspace and to Outlook users from Microsoft 365. Tell us roughly how your list splits and we suggest a mix.
Enterprise, finance, healthcare and government skew Outlook. Startups and tech skew Google.
Inboxes in total
Google Workspace
18
inboxes
Microsoft 365
12
inboxes
A mixed list: run both and send each segment from the matching provider.
FAQ
How much to send, from how many inboxes, on how many domains.
01
Per inbox, 20 to 40 cold emails a day once it is warmed up, and around 10 a day in the first week of campaigns. Your total daily volume is that number multiplied by your inboxes: 30 inboxes at 30 a day is 900 cold emails a day.
02
Divide your daily goal by the emails each inbox sends. At 30 per inbox per day, 500 cold emails a day needs 17 inboxes, 1,000 needs 34 and 5,000 needs 167. The calculator above does the maths, including domains and cost.
03
We recommend up to five inboxes per domain. Going lower, for example two or three, spreads your volume across more domains, so a problem on one domain affects fewer inboxes.
04
There is no fixed number. Gmail and Outlook judge complaints, bounces and engagement, not a count: Google asks bulk senders to keep the spam rate under 0.3%, ideally under 0.1%. Low volume per inbox, verified lists and relevant messages keep you out of spam.
05
A Google Workspace user can send 2,000 messages a day (500 on a trial) to up to 3,000 unique recipients. That is a hard ceiling, not a target: for cold email stay at 20 to 40 a day per inbox.
06
A Microsoft 365 mailbox can send to 10,000 recipients a day and 30 messages a minute, with extra caps on new tenants for their first 60 days. For cold email stay at 20 to 40 a day per inbox.
07
About three to four weeks: two weeks of warm-up only, a week at roughly a third of your target, then full volume with warm-up still running in the background.
Still have a question? [email protected] · contact us
Google Workspace and Microsoft 365 inboxes from $2.90 a month, set up and connected to your sequencer today.