Free tool
Mailbox warmup calculator
Work out a sending ramp for a new outreach mailbox before you start: how long until you're at full volume, how much you can send while warming up, and what several mailboxes add up to.
Full volume after
0 days
Sent in the first 30 days
0
Per month at full volume
0
Daily cap per mailbox
First 6 weeks
| Week | Daily cap (per mailbox) | Emails that week (all mailboxes) |
|---|
Using the numbers
The ceiling is the number that matters for planning. A link outreach campaign that needs 3,000 pitches a month is a three- or four-mailbox job, not one mailbox pushed to 100 a day. Set up the extra mailboxes on separate domains at the start, so they all finish warming up together.
Watch these while you ramp
- Bounces above 3–5%. Stop and clean the list. Verify addresses before they're added, not after they bounce.
- Replies. Early replies are the best signal you can send a provider. Your first week should go to your best-fit prospects.
- Spam placement. If a test email to your own Gmail account lands in spam, pause the ramp for a few days rather than pushing on.
Set up SPF, DKIM and DMARC on the sending domain before day one. Without them, no ramp helps much.
Warmup is only one part of a safe sending setup. The outreach deliverability guide covers domains and authentication, and if you plan to send from Google Workspace, read Workspace limits and risks for outreach before you buy seats. Once you're sending, watch bounces closely during the ramp: the email bounce rate calculator tells you when to pause.
Questions people ask
Why do new mailboxes need warming up?
Gmail and Outlook judge a sender partly on history. A brand-new domain that suddenly sends 50 cold emails a day looks exactly like a spammer, so those emails land in spam. Starting small and rising gradually builds a track record of delivered, opened and replied-to mail.
How long does warmup take?
It depends on the ceiling you're aiming for and how fast you climb. BacklinkGenie's own ramp starts at 4 emails a day and adds 2 every other day, reaching 35 a day after about a month. Going faster saves a week or two but raises the risk of an early spam-folder streak that's slow to recover from.
How many outreach emails per mailbox per day is safe?
For one-to-one, personalized outreach, 30 to 50 a day per mailbox is a common ceiling. More than that and replies, bounces and complaints are harder to keep healthy. If you need more volume, add mailboxes on separate domains rather than pushing one harder.
Should I send outreach from my main company domain?
Better not. Use a separate domain for cold outreach so a bad week can't affect the deliverability of your invoices, password resets and customer email. Point it at your main site so recipients who look it up land somewhere real.
Does warmup still matter if every email is personalized?
Yes. Providers can't see your intent, only your sending pattern and how recipients react. Personalization helps a lot with the reaction part (replies, few spam reports), but volume still needs to rise gradually.
Related
SPF, DKIM and DMARC checker
Look up a domain's live SPF, DKIM and DMARC records and see what's wrong in plain English: duplicate SPF, too many lookups, a weak DMARC policy.
Outreach volume planner
Start from the number of links you want a month and work back to pitches, prospects and mailboxes, including warmup time.
Email deliverability for link outreach
Domain, authentication, warmup and sending limits for outreach that reaches the inbox.
See where your next links could come from.
Paste your URL. The agent finds lists, comparison pages, resource pages and guides where your product fits, checks each site and finds the editor to contact. Free, no card.
