Enter your domain age, provider, and target volume. Get a safe day-by-day or week-by-week warmup schedule with risk level and provider limit warnings.
Inbox warmed up? Now send personalized cold emails at scale.
WarmOpener generates AI-personalized emails for your entire prospect list using your own OpenAI key at $0.002 per email.
Approximate cost: $6/mo per inbox — you need one inbox per 30 cold emails/day
Total cold emails you want to send per day across all inboxes
Enter your target daily volume to see your warmup plan
Each inbox can safely send max 30 cold emails/day. We'll tell you how many you need.
Email warmup is the process of gradually increasing your daily send volume so ISPs like Google and Microsoft build a positive reputation score for your domain. Send too much too fast from a new inbox and your emails go straight to spam or your account gets suspended. A proper warmup schedule builds that trust incrementally over several weeks.
The single most important number in cold email warmup is 30. Regardless of what your provider technically allows, sending more than 30 cold emails per day from a single inbox damages your sender reputation. ISPs track behavioral signals like open rates, reply rates, and spam complaints per sending address. Staying at 30 or below keeps those signals healthy. If you need to send more, you add more inboxes — not more volume per inbox.
Simple math: divide your target daily volume by 30. Want to send 90 emails/day? You need 3 inboxes. Want to send 300/day? You need 10 inboxes. Each one needs to be warmed up separately over several weeks before you can send cold outreach from it. Most cold email senders underestimate this — they set up one inbox and try to blast 200 emails on day one, which gets them blacklisted within a week.
For a brand-new domain, expect 6 to 7 weeks before any single inbox is safely at 30/day. For domains that are a few months old, you can reach 30/day in about 4 to 5 weeks. Older domains with existing sending history can warm up in as little as 3 weeks. There are no shortcuts here: trying to compress a 6-week schedule into 2 weeks is how domains get permanently blacklisted.
WarmOpener generates AI-personalized cold emails for your entire prospect list. Upload a CSV, let AI fetch each website, and send at $0.002 per email with your own OpenAI key.