Shared or Dedicated IP for Email? A Volume-Based Answer

Use a shared IP unless you send a large, steady volume. Amazon SES recommends shared IPs for anyone who does not send "large volumes of email on a regular and predictable basis". SendGrid suggests a dedicated IP only above 50,000 emails a month, Mailgun above 50,000 a week, and Postmark requires at least 300,000 a month.

Those numbers do not agree with each other, and that is the useful part. The rest of this post lines up what each provider actually publishes (fetched on 1 October 2026), turns it into one decision table, and explains the two things that matter as much as volume: how regular your sending is, and whether the problem you are trying to fix is an IP problem at all.

What a dedicated IP actually changes

A dedicated IP means your mail is the only mail sent from that address, so the IP's reputation reflects only your sending. On a shared IP, your reputation is pooled with other customers of the same provider.

Google states it plainly: "The activity of any senders using a shared IP address affects the reputation of all senders for that shared IP address" (Google sender guidelines). That cuts both ways. A neighbour's bad campaign can hurt you, but the pool's steady volume also keeps the IPs known to mailbox providers, which a small sender cannot do alone.

Amazon SES's documentation summarises the trade-off well. On shared IPs, "your sender reputation is set at the account level and can't be isolated". On dedicated IPs, "your sender reputation is completely under your control", which also means it is entirely your responsibility (Amazon SES).

What it does not change is your domain reputation. Mailbox providers judge the domain separately: Yahoo, for example, notes that "each IP and DKIM domain has a reputation" (Yahoo Sender Hub). A dedicated IP will not rescue a domain that has been sending to bad lists.

What each provider publishes

Every major ESP recommends shared IPs for low-volume senders, but they draw the line in different places and in different units. Here are the thresholds as each one states them.

Provider	What they say about when to go dedicated	Source
SendGrid	"A dedicated IP is only recommended if you are sending more than 50,000 emails each month." Suggests at least 2 dedicated IPs at 200-300K/month	Warm-up guide, support article
Mailgun	"If you are sending a lot of email (greater than 50K per week), it is best to isolate your reputation by having a dedicated IP address." Under 5,000 a day, "a shared IP may be the right solution"	Mailgun docs
Postmark	"To qualify for a dedicated IP, you must send at least 300,000 messages a month." An additional IP at 100,000+ messages a day	Postmark
Amazon SES	Use shared IPs unless you send "large volumes of email on a regular and predictable basis". For each mailbox provider, send "several hundred emails within a 24-hour period at least once per month"	SES docs

Converting them to the same unit shows how far apart they are:

Provider threshold	Per month (approx.)	Per day (approx., 30-day month)
SendGrid: 50,000 a month	50,000	1,700
Mailgun: 50,000 a week	215,000	7,100
Mailgun: under 5,000 a day, shared may suit	under 150,000	under 5,000
Postmark: 300,000 a month minimum	300,000	10,000

The spread runs from about 50,000 to 300,000 a month. Postmark's line is the strictest and is a hard eligibility rule rather than a suggestion. SendGrid's is the loosest. Neither is wrong; they reflect how much each provider trusts its own shared pools and how much warm-up support it gives.

The decision table

Below about 50,000 a month, use shared IPs. Between 50,000 and 300,000, it depends on regularity and provider. Above 300,000 a month of steady mail, a dedicated IP is normal practice. The table combines the published thresholds with the regularity rule.

Monthly volume	Sending pattern	Recommendation	Why
Under 50,000	Any	Shared	Below every provider's published threshold
50,000 - 150,000	Daily and steady	Shared, or dedicated if your ESP recommends it at this level (SendGrid does)	Above SendGrid's line, below Mailgun's and Postmark's
50,000 - 150,000	Bursty (one big weekly or monthly send)	Shared	SES advises against dedicated IPs for irregular patterns
150,000 - 300,000	Daily and steady	Dedicated is reasonable	Around Mailgun's 50K-a-week line; SendGrid suggests 2 IPs at 200-300K
150,000 - 300,000	Bursty	Shared, or SES managed dedicated IPs	SES positions managed IPs for "less predictable sending patterns"
Over 300,000	Daily and steady	Dedicated, separate streams for marketing and transactional	Meets even Postmark's minimum
Over 300,000	Bursty	Dedicated with care, or managed	Volume justifies it; spikes still hurt a lone IP

"Steady" here means mail goes out most days to each major mailbox provider. A newsletter list of 100,000 that is mailed once a month sends a large spike and then nothing, which is the pattern every provider warns about.

Volume is not enough: the regularity test

The second requirement is that each major mailbox provider sees a steady flow from the IP, not just that the monthly total is high. Providers judge an IP by its recent history, and an IP that goes quiet loses that history.

The published rules on this are specific:

• Amazon SES: after warm-up, "you should send around 1,000 emails every day to each email provider that you want to maintain a positive reputation with" (SES warm-up).
• Postmark: if sending drops below 20,000 messages a week for four consecutive weeks, the IP has to restart its warm-up (Postmark).
• Gmail: "Avoid introducing sudden volume spikes if you do not have a history of sending large volumes" (Google).

A worked example. Suppose you send 60,000 emails a month, which clears SendGrid's threshold. If that goes out as a single newsletter on the first of the month, the IP is silent for the other 29 days and every send is a spike. If instead it is 2,000 a day of receipts and notifications, the IP has a steady history. Same total, opposite answer: the first sender belongs on a shared IP, the second could reasonably use a dedicated one.

What it costs, as of October 2026

Dedicated IPs typically cost tens of dollars per IP per month, plus the plan tier that allows them. These are the published figures we could read on each provider's pricing page on 1 October 2026.

Provider	Dedicated IP pricing	Source
Amazon SES	Standard: $24.95 per IP per month. Managed: $15 per account per month plus $0.08 per 1,000 emails (first 10M)	SES pricing
SendGrid	Pro plan from $89.95/month with 1 dedicated IP included (Essentials, from $19.95, uses shared IPs). Extra IP price not listed on the page	SendGrid pricing
Mailgun	One dedicated IP included with Foundation 100k, Growth and Scale plans; additional IPs $59 per IP per month	Mailgun pricing
Postmark	$50 per IP per month, only at 300,000+ messages a month	Postmark
Mailchimp Transactional	Optional dedicated IP add-on at $29.95 per month	Mailchimp

The IP fee is rarely the real cost. The real cost is the warm-up period and the ongoing need to keep volume steady.

Warm-up: the cost people underestimate

A new dedicated IP has no history, so it has to be warmed up over weeks before it can carry full volume. On a shared IP, that work has already been done by the pool.

SES says establishing a positive reputation can take "around two weeks" with some providers and "up to six weeks" with others, and its automatic warm-up runs over 45 days (SES warm-up). SendGrid says warm-up "can last up to 60 days", with most of its customers finishing within 30 (SendGrid). The day-by-day mechanics are in our warm-up schedule.

During warm-up, mail that cannot go through the new IP has to go somewhere else. SES and SendGrid both handle this by splitting traffic with other IPs while the new one ramps up. If you have nothing else to fall back on, warm-up means sending less.

Where the IP question does not apply: cold email

If you send cold email from Google Workspace or Microsoft 365 inboxes, there is no IP to choose; you are on the provider's infrastructure. Your levers are the domain, the inboxes and the list.

It is easy to read about dedicated IPs and assume an outbound team needs one. For cold outreach, the equivalent decision is how many secondary domains and inboxes to run, and keeping bounces out of them by verifying lists before sending. A dedicated IP behind a bulk ESP is a different sending model altogether.

Signs you picked the wrong one

A dedicated IP is wrong for you if its reputation never settles; a shared IP is wrong for you if a neighbour's problems keep reaching your mail. Each has a recognisable pattern.

Dedicated, but under-volume:

• Postmaster Tools IP reputation swings from day to day or shows gaps. Google notes dashboards "might not include all data on days when your outgoing email volume is low" (Google).
• Deliverability is good after a busy week and poor after a quiet one.
• Your ESP asks you to re-warm the IP.

Shared, but outgrown it:

• Delivery problems appear that you cannot trace to your own list, complaints or authentication.
• You need to separate transactional mail from marketing so a campaign problem cannot delay password resets. SES notes that dedicated IP pools let you put marketing and transactional mail on separate IPs (SES).
• You want to see per-IP data in Microsoft's SNDS, which only shows "the IPs for which you are responsible" (SNDS).

If your sender reputation has already been damaged, move IPs only after fixing the cause; the 30-day recovery plan explains why.

The short version

• Shared IPs suit almost everyone under about 50,000 emails a month, and anyone whose sending comes in bursts.
• Published thresholds range from 50,000 a month (SendGrid) to 300,000 a month (Postmark, a hard minimum).
• Regularity matters as much as volume: SES suggests about 1,000 a day to each provider after warm-up; Postmark re-warms after four weeks under 20,000 a week.
• A dedicated IP costs roughly $25 to $59 per month at the providers above, plus weeks of warm-up.
• It does nothing for domain reputation, and for cold email from Workspace or 365 inboxes the choice does not exist.

Whichever you choose, authentication still decides a lot of placement; a deliverability audit checks SPF, DKIM and DMARC for your domain in a few seconds.