IP warming is raising volume from a new IP address gradually, so mailbox providers can build a record of how it behaves. It applies when the IP is yours, which in practice means a dedicated IP on an email platform.
On Google Workspace or Microsoft 365 the IP is shared. Your equivalent job is warming the domain and the mailboxes on it.
Most people who search for this can’t do it.
Send cold email from Workspace or Microsoft 365 and the sending IP belongs to Google or Microsoft, shared with thousands of other senders. You can’t warm it, and you don’t need to.
This page sorts you into one of three groups, then tells you what your actual job is.
Key Takeaways
- IP warming means raising volume from a new sending IP slowly, so providers judge it on evidence rather than suspicion.
- On Google Workspace or Microsoft 365 the IP is shared and managed for you. Warm your domain and mailboxes instead.
- There’s no single schedule. Published vendor ramps run from one week to sixty days.
- A dedicated IP only pays off at real volume. An underfed one performs worse than a shared pool.
- Authenticate first. Ramping a domain that fails SPF or DKIM only proves the failure faster.
What Is IP Warming, and What Does “IP Warm Up” Mean?
They’re the same thing. You raise volume from a new or dormant sending IP in steps rather than going straight to full speed. The provider watches how it behaves.
A cold IP has no sending history, so providers have nothing to judge it on. They throttle it, defer some mail and watch. Send a thousand messages on day one and the pattern looks exactly like a spam run.
Warming gives them evidence instead: small volumes, engaged recipients, steady growth.
One thing worth holding onto: providers score the IP and the domain separately. They’re two reputations with two different owners.
Confusing them is why so much advice on this topic doesn’t apply to the person reading it.
Does IP Warming Even Apply to You?
Before you plan a ramp, work out whether the IP is yours to warm.
If You Send From Google Workspace or Microsoft 365
It isn’t yours. You’re on a shared pool, and Google or Microsoft manages that reputation across every tenant on it.
Google doesn’t hand out a dedicated outbound IP on a normal Workspace plan. Getting one means routing outbound mail through a separate gateway. That’s an infrastructure project, not a setting.
Microsoft doesn’t offer them to ordinary senders either, and its High Volume Email option lost external sending in June 2025.
What does apply to you is the Workspace sending limits your plan sets, and SMTP warmup if you relay through your own server.
So the ramp schedules elsewhere on this topic aren’t your job. Yours is the two reputations you control: the sending domain and each mailbox on it.
If You Have or Are Buying a Dedicated IP
Then yes, warm it. The section below is written for you.
| Your setup | Warm the IP? | Warm domain and mailboxes? | What to do |
|---|---|---|---|
| Cold outreach on Google Workspace | No | Yes | Warm the domain and every mailbox on it |
| Cold outreach on Microsoft 365 | No | Yes | Same, and watch Outlook filtering separately |
| New dedicated IP on an email platform | Yes | Yes, if the domain is new too | Follow your platform’s published ramp |
| Shared IP on an email platform | No, handled for you | Yes | Focus on the domain and on engagement |
Most people reading this land in one of the first two rows, where the answer is no.
What’s the Difference Between IP, Domain and Mailbox Warming?
Three different reputations, and the column that decides which ones matter to you is who controls it.
| Type | Warms what | What it protects | Who controls it | Who needs it |
|---|---|---|---|---|
| IP warming | The sending IP | IP reputation | Your email platform, or you if the IP is dedicated | High-volume senders on a dedicated IP |
| Domain warming | The sending domain | Domain reputation | You, always | Every sender |
| Mailbox warming | The individual mailbox | Mailbox and sender trust | You | Cold outreach senders |
The two rows you control are the two that most guides skip.
What Happens if You Skip IP Warming?
It doesn’t usually fail loudly, it degrades, and it does so in a fairly predictable order.
First deferrals, where the server accepts the connection but asks you to try later. Then throttling, where less of your mail gets through per hour. Then outright blocks.
By that point the damage is to the reputation, not to one campaign.
A blocked send is a bad day. A damaged sender reputation is a slow recovery, because providers need a run of good behaviour first.
On a shared pool this is managed for you. That’s a genuine benefit and a real limit. You inherit the pool’s reputation, good or bad, and can’t ramp your way out of it.
How Do You Warm Up an IP Address?
Authenticate first. SPF, DKIM and DMARC need to pass before a single message goes out. Ramp a known failure and you only teach providers to distrust you faster.
Then:
- Start small, and only to your most engaged recipients.
- Raise volume gradually. Roughly doubling per day is the usual ceiling.
- Watch bounces, complaints and deferrals, not open rates.
- If a metric slips, hold volume rather than pushing through.
- Keep sending. An IP that goes quiet cools off and has to be warmed again.
Most platforms automate this, and it’s usually the safer choice, because it reacts to the response rather than following a calendar.
Watch what providers report back – Google Postmaster Tools covers personal Gmail only, and Microsoft SNDS covers Outlook.com and needs you to control the IP.
What Ramp Schedule Does Each Major ESP Publish?
Every vendor publishes a schedule. Nobody compares them, and the spread is the finding.
| Provider | Published ramp | Automated? |
|---|---|---|
| Twilio SendGrid | Up to 60 days, most within 30, some in one to two weeks | Yes |
| Amazon SES | Automatic warmup up to 45 days | Yes |
| Mailgun | 100 emails on day one, then about +20% a day | Manual guidance |
| LuxSci | Starts at 20 messages an hour, steps up only if 90% of the day’s allowance is used | Yes |
| SparkPost | Roughly 30 days | Yes |
| Rejoiner | 15 to 60 days, roughly doubling through the first 15 | Manual |
| Oracle Responsys | A day-by-day table, split by receiving provider | Manual |
There’s no universal schedule, so anyone quoting one exact ramp is quoting their own platform. The shape matters more than the numbers, and a smooth climb beats a spike at any volume.
How Long Does IP Warming Take?
Two to six weeks, for most senders.
That range comes from the table above rather than a number we picked. Where you land depends on your target volume, how engaged your recipients are, and whether the domain is new too.
A new IP on an established domain warms faster, because one of the two reputations is already built.
Do You Even Need a Dedicated IP?
Usually not. The thresholds are higher than most people expect, and they are published.
| Provider | Threshold | Notes |
|---|---|---|
| Postmark | 300,000 messages a month | Re-warming required if volume drops below 20,000 a week for four weeks |
| Mailgun | 100,000 messages a month | Paid add-on |
| Amazon SES | No enforced minimum | Has historically recommended sustained high daily volume |
| Google Workspace | Not offered without an outbound gateway | Shared pool by default |
| Microsoft 365 | Not offered to ordinary senders | Use a dedicated sending platform |
A dedicated IP needs consistent volume to stay warm. An underfed one performs worse than a shared pool, because providers see a stranger every time you send.
Cold outreach volumes almost never clear these thresholds. Reading this from a Workspace or Microsoft 365 mailbox? Then the answer is no.
Run the deliverability checklist before you change anything.
Close
The number that matters isn’t the ramp. It is whether the IP is yours at all.
For most cold email senders it isn’t. The work that moves your delivery is warming the domain and the mailboxes you control.
Frequently Asked Questions
What Is IP Warming?
Raising volume from a new IP gradually, so providers judge it on behaviour rather than treating it as an unknown. It applies to dedicated IPs. On a shared pool the provider handles it.
How Long Does IP Warming Take?
Two to six weeks for most senders. Published vendor ramps run from one to two weeks at the fast end to sixty days at the slow end. Target volume and engagement move it.
How Do You Warm Up an IP?
Authenticate first, then send small volumes to your most engaged recipients and raise them gradually, never more than roughly doubling in a day. Hold volume if bounces, complaints or deferrals slip.
Do I Need IP Warming on Google Workspace or Microsoft 365?
No. Both send from shared IP pools that they manage, so the IP isn’t yours to warm. Warm your sending domain and each mailbox instead, which are the two reputations you do control.
Is IP Warming the Same as Domain Warming?
No. They’re separate reputations, scored separately. The IP belongs to your platform unless it’s dedicated to you. The domain is always yours, which is why domain warming applies to every sender and IP warming doesn’t.
What Is IP Warming in Salesforce Marketing Cloud?
The same process inside Salesforce Marketing Cloud, which assigns sending IPs to accounts and asks senders to ramp new ones gradually. The principle doesn’t change with the platform. Follow the ramp your account’s documentation publishes.
