Domain age, authentication, mailbox provider, and target volume all change how long warmup should take. Answer the questions below and get a week-by-week sending schedule, plus an A to F score of your live SPF, DKIM, and DMARC records. Not a generic "wait four weeks" rule.
Fill in the form and your personalized warm-up schedule will appear here, including any warnings specific to your setup.
The base timelines are not arbitrary. They are built from three sources: Google and Microsoft's published bulk sender requirements, the sending caps that mailbox providers apply before flagging an account, and benchmarks used across the cold email industry for what a safe daily increase looks like.
The A to F grade is not a vibe. It is scored directly against the specs that mailbox providers implement, weighted SPF 35, DKIM 30, DMARC 35, and rescaled to 100.
+all scores near zero: it authorizes every server on the internet to send as you, which is worse than publishing nothing, because forgeries then pass authentication.p= tag explicitly revokes a key under RFC 6376 section 3.6.1, so a checker that only asks whether p= exists will call a revoked key healthy. Key length and the t=y test-mode flag are scored too. If no selector matches, DKIM is dropped from the score rather than counted as zero, and the result is marked as unverified.sp= governs subdomains. We also read pct=, because p=reject; pct=10 only enforces on a tenth of failing mail and is much closer to p=none than to reject.We are collecting anonymous, aggregated outcome data from calculator use (inputs and computed plan only, never domain names or personal information) to refine these numbers over time. That data is self-selected, being people who chose to run a warm-up calculator rather than a random sample of senders, and we will say so plainly whenever we publish from it.
SPF, DKIM, and at least a DMARC record set to none are not optional extras. Warming up an unauthenticated domain builds reputation for a sender mailbox providers cannot verify, and that reputation does not transfer once you fix authentication later.
A dedicated sending subdomain isolates cold outreach from the email your company depends on for support, billing, and internal communication. It still inherits some trust from your root domain without putting it at risk, and it inherits your DMARC policy too.
Open rates are increasingly unreliable due to image blocking and privacy features in mail clients. Replies and manual moves out of spam are what actually build sender reputation during warm-up, which is the specific gap automated warm-up tools are built to fill.
Tracking a ramp schedule across multiple mailboxes, catching messages that land in spam, and getting real replies to build engagement signals is manageable in a spreadsheet for a week or two. Past that, it is the exact set of tasks lemwarm automates inside the same account you already use to send sequences.
Start your 14 day free trialIt depends on domain age and authentication, not a flat rule. A brand new domain with no SPF, DKIM, or DMARC needs 8 to 10 weeks. A domain that is a year old with full authentication and some sending history can be ready in 1 to 2 weeks. Use the calculator above for a number based on your specific setup.
You can, but it is not the safer choice. Cold outreach volume behaves differently from transactional or marketing email, and a reputation dip during warm up can affect every other email your company sends. A dedicated subdomain (like send.yourcompany.com) isolates that risk while still inheriting some trust from the root domain.
Usually not. If send.yourcompany.com has no DMARC record of its own, receivers fall back to the policy published at yourcompany.com, and the sp= tag on that record is what governs subdomains (falling back to p= when sp= is absent). This is defined in RFC 7489 section 6.6.3. Many DNS checkers skip that fallback and report "no DMARC" for a subdomain that is in fact fully covered, so a missing record on the subdomain alone is not evidence of a problem. Our checker reports the inherited policy and tells you where it came from.
Almost certainly not. DKIM has no fixed lookup location: the selector is chosen by whoever configured sending, so any checker can only try a list of common ones. Google Workspace is the clearest example, since its default selector is a rotating date string that cannot be guessed, which means google.com itself returns nothing for every common selector. A miss means we could not confirm DKIM, not that it is missing, and we leave it out of the score rather than grading you down for it.
Gmail and Outlook have no history to judge your domain by, so they lean on caution. That usually shows up as low inbox placement, mail routed straight to spam or promotions, and in worse cases a blocked or rate-limited sending domain that takes weeks to recover from, longer than warming up properly would have taken.
No, they solve different problems. This calculator tells you how long your warm-up should take and what daily volume to send at each stage. lemwarm is what actually executes that ramp: it sends and receives mail inside a real network of inboxes, marks messages as not spam, and moves replies out of promotions automatically, things that are hard to do manually at any real scale.
The base timelines follow published Google and Microsoft bulk sender guidance and widely used cold email industry benchmarks for sending caps by mailbox provider. The authentication score follows the relevant specs directly: RFC 7208 for SPF lookup limits, RFC 6376 for DKIM key state, and RFC 7489 for DMARC policy and inheritance. We explain the exact modifiers in the methodology section below the calculator.