Email warmup schedule calculator
This email warmup schedule calculator builds a day-by-day ramp for new cold email inboxes: how many cold emails each inbox sends each day, when it reaches full volume, and when your team hits its daily target. Enter your own plan to get your schedule.
Your inputs are saved only in this page address, so you can bookmark or share them. Nothing is stored anywhere else.
How long should you warm up a new email inbox?
Plan on two weeks at minimum and three to four weeks for a brand-new domain. Instantly gives a "hard minimum of 2 weeks" before cold outreach. During warmup the inbox sends and receives a small number of normal-looking emails, so mailbox providers see steady, low-risk activity before any cold email goes out.
What does a safe ramp look like day by day?
Start small and add a few cold emails per inbox each day until you reach a cap. Instantly's published plan sends 10 to 18 a day on days 4 to 7, 20 to 28 on days 8 to 14, and caps at 30 from day 15. For more volume it says to add warmed inboxes, not push one higher.
This calculator uses a straight-line version of that idea: warmup-only days, then a starting volume that rises by a fixed amount each day until the cap. Change any input to match the plan you actually run.
How many cold emails per inbox per day?
Instantly recommends keeping campaign sends at or below 30 per inbox per day, and suggests holding caps in the 25 to 30 range. If you need more total volume, add inboxes and domains rather than raising the cap. The cold email domains calculator works out how many inboxes and domains a daily volume needs.
When should you pause the ramp?
Pause and investigate when bounces go above about 1%, spam complaints approach 0.3%, or seed tests show inbox placement falling. Instantly lists those three triggers and suggests resuming at a lower cap once the numbers have been stable for 48 hours. Gmail and Yahoo both tell senders to keep spam rates below 0.3%.
The formula
cold emails per inbox on day d = 0 while d is a warmup-only day
after warmup: min(cap, start + daily increase x sending days so far)
day each inbox reaches its cap = warmup days + round up((cap - start) / daily increase) + 1
daily capacity = inboxes x cap
inboxes needed = round up(target / cap)
The week-by-week table shows the per-inbox and total daily volume on the last day of each week. Ongoing warmup sends are not counted as cold emails.
Frequently asked questions
Can I skip warmup if I buy pre-warmed inboxes?
Pre-warmed inboxes have some sending history, but the domain and your sending pattern are still new to mailbox providers. Most guides still ramp cold volume gradually for the first weeks.
Should warmup keep running after the ramp?
Instantly suggests keeping roughly 20 to 30 percent of daily volume for ongoing warmup after the ramp. Leaving it on helps keep inbox placement steady.
Why does my target day show as not reached?
Your target is above what your inboxes can send at the cap. Add inboxes, or lower the target. The results show how many inboxes the target needs at your cap.
Does this calculator store my numbers?
No. The math runs in your browser. Your inputs are written into the page address so you can bookmark or share them. Nothing is sent to a server, and the site uses no cookies or trackers.
Sources
- Instantly: Slow ramp plan for new cold email domains. Day-by-day ramp, 30 per inbox cap, and pause thresholds.
- Instantly: How to warm up an email domain. Two-week minimum, three to four weeks for new domains, ongoing warmup share.
- Google: Email sender guidelines. Spam rate guidance for senders to Gmail.
- Yahoo Sender Hub: Sender best practices. Spam rate guidance for senders to Yahoo.
Checked October 25, 2026.