Key takeaways
- On a shared IP, your reputation is pooled with other senders managed by the provider.
- On a dedicated IP, your reputation depends only on you, for better and for worse.
- Dedicated IPs need high, steady volume; a common rule of thumb is well over 100,000 emails per month.
- Low or irregular volume on a dedicated IP often gives worse results than a good shared pool.
- Domain reputation matters more and more; a dedicated IP does not fix a weak domain.
In this guide
- What a sending IP is
- How a shared IP works
- How a dedicated IP works
- Side-by-side comparison
- The volume question
- Domain reputation changes the equation
- Decision checklist
- Can you use both?
- Moving to a dedicated IP: what to plan
- Questions to ask your email provider
- Two short case examples
- Reverse DNS and dedicated IPs
- Dedicated IP and IP pools
- Myths about dedicated IPs
- Frequently asked questions
What a sending IP is
Every email is delivered by a server with an IP address. Mailbox providers record how mail from each IP behaves, in addition to how mail from each domain behaves. When you use an email platform, you send through its IP addresses. The question is whether you share those IPs with other customers or have one or more reserved for you alone.
How a shared IP works
On a shared IP, many senders use the same pool of addresses. The provider manages the pool: it monitors complaints and bounces, removes customers who send badly, spreads traffic, and keeps volume steady.
- Pooled reputation: your occasional campaign benefits from the steady, good traffic of other senders.
- No warm-up of the IP: the IPs are already active and known to mailbox providers.
- Managed for you: the provider handles technical setup, monitoring and blocklist issues.
- Included in standard plans: no extra cost.
The trade-off: you depend on the provider's discipline. A good provider removes bad senders quickly. A careless one lets them damage the pool.
How a dedicated IP works
A dedicated IP is used only by you. Its reputation is entirely built by your sending.
- Full control: no other sender can affect your IP reputation.
- Clear diagnosis: IP-level data, such as Microsoft SNDS, reflects only your traffic.
- Predictability at scale: large senders get stable, consistent results.
The trade-off: you are alone. If you send irregularly or to a dirty list, there is no good traffic from others to balance it. And a new dedicated IP has no reputation: it must be warmed up, which takes weeks.
Side-by-side comparison
| Criterion | Shared IP | Dedicated IP |
|---|---|---|
| Reputation | Pooled with other senders | Only yours |
| Minimum volume | None | High and steady |
| Warm-up | Not needed for the IP | Required, several weeks |
| Cost | Included | Add-on or higher-tier plan |
| Risk from others | Low with a good provider | None |
| Risk from your own mistakes | Diluted | Fully on you |
| Best for | Most small and medium senders | High-volume senders with consistent programs |
The volume question
There is no official threshold, but the logic is simple: mailbox providers need enough regular traffic from an IP to form an opinion. With low volume, an IP never builds a stable reputation, and each campaign looks like a new event.
As a rule of thumb, a dedicated IP starts to make sense when you send well over 100,000 emails per month, regularly, several times a week. Many specialists recommend higher volumes still. Below that, a good shared pool usually delivers better.
A business sends 30,000 emails once a month and buys a dedicated IP "to be professional". Each monthly send hits cold infrastructure, gets throttled and partly filtered. Back on a shared pool, results improve. Volume and consistency matter more than ownership.
Domain reputation changes the equation
Years ago, IP reputation was the main factor. Today, mailbox providers rely heavily on domain reputation, tied to the authenticated domain in your From address and DKIM signature. This has two consequences:
- A dedicated IP does not fix a weak domain. If your list or practices are the problem, it follows you to any IP.
- On a shared IP, your domain reputation is still yours. Bad senders on the same pool affect the IP, not your authenticated domain.
That is why authentication is the first investment, before any IP decision. See SPF, DKIM and DMARC explained and how sender reputation works.
Decision checklist
Choose a dedicated IP only if you can answer yes to most of these:
- You send more than roughly 100,000 emails per month, every month.
- You send several times per week, with predictable volume.
- Your list is clean: bounce rate under 2%, complaints under 0.1%.
- You have the time and tools to monitor IP-level data.
- You can follow a warm-up plan of several weeks.
- You need to isolate streams, for example transactional mail with strict delivery needs.
If several answers are no, stay on a well-managed shared IP and focus on list quality and engagement.
Can you use both?
Yes, and many larger senders do. A typical setup: transactional email (receipts, password resets) on a dedicated IP with very steady volume, and marketing on a shared pool, or the reverse depending on volumes. Using separate subdomains for each stream also helps; see sending from a subdomain.
Moving to a dedicated IP: what to plan
- Clean your list first. Verify addresses and remove long-inactive contacts. See how to clean your email list.
- Authenticate the sending domain and check reverse DNS for the IP (your provider usually handles this).
- Follow a warm-up plan, starting with your most engaged contacts. See email warm-up.
- Monitor Postmaster Tools, Microsoft SNDS, bounces, complaints and blocklists.
- Keep volume steady once warm. Long gaps cool the IP down again.
Questions to ask your email provider
- How do you monitor shared IP pools, and how fast do you remove bad senders?
- Do you separate pools by sender quality or type of mail?
- From which plan is a dedicated IP available, and what does it cost?
- Do you offer an automated warm-up for new dedicated IPs?
- Who handles blocklist issues on a dedicated IP: you or me?
- Can I move back to a shared pool if my volume drops?
The answers tell you a lot about the provider. A good one explains its pool management clearly and does not push a dedicated IP on low-volume senders.
Two short case examples
A monthly newsletter of 20,000 contacts
One send per month means about 20,000 emails monthly. That is far too little and too irregular for a dedicated IP. The right setup is a reputable shared pool, an authenticated domain and a clean list.
An e-commerce brand sending 600,000 emails per month
Daily campaigns plus automations, a steady volume and a clean list. A dedicated IP (or several) gives control and clearer data. The brand plans a six-week warm-up and keeps transactional mail on a separate stream.
Reverse DNS and dedicated IPs
Every sending IP should have a valid reverse DNS (PTR) record that points to a host name, which in turn resolves back to the same IP. Gmail and Yahoo list this among their requirements. On shared platforms, the provider configures it. With a dedicated IP, check that the PTR record exists and, if your provider allows it, uses a host name related to the provider or your sending domain. A missing or generic PTR record is a classic reason for rejections on new dedicated IPs.
Dedicated IP and IP pools
Large senders sometimes use several dedicated IPs as a pool, for example one per stream or per country. More IPs need more volume: each one must receive enough steady traffic to keep its reputation. Splitting a moderate volume across many IPs leaves each of them cold. Start with one and add more only when volume clearly justifies it.
Myths about dedicated IPs
- "A dedicated IP guarantees the inbox." No. It only gives you sole responsibility for the IP's reputation.
- "Shared IPs are for amateurs." Many professional programs run on shared pools because they deliver better at their volume.
- "My emails are in spam because of other senders." Possible, but rare with a good provider. Check your own authentication, list quality and complaint rate first; see why emails go to spam.
Frequently asked questions
Is a dedicated IP better for deliverability?
Only for senders with high, regular volume and good practices. For smaller senders, a well-managed shared IP usually delivers better.
How much does a dedicated IP cost?
It depends on the provider. It is usually a paid add-on or included in higher-tier plans. With Brevo, a dedicated IP is available on the higher plans.
Can other senders ruin my reputation on a shared IP?
Reputable providers monitor and remove bad senders quickly, so the risk is limited. Your domain reputation remains your own in any case.
Do I need to warm up a dedicated IP?
Yes. A new dedicated IP has no history and must be warmed up gradually over several weeks.
What volume justifies a dedicated IP?
There is no official number, but a steady volume above roughly 100,000 emails per month, sent several times a week, is a common starting point.
