Article Email

IMAP or POP3: which should you choose?

The difference between the two ways an email app can fetch your mail, and why IMAP is the right default for almost everyone now.

iFastHosting Support Team Updated 26 August 2026 8 min read Beginner

Every mail app asks the same question when you set up an account, usually in a screen you click past without reading: IMAP or POP3? Both protocols do the same basic job — they fetch messages from a mail server so your app can show them to you — but they disagree completely about where the mail actually lives afterwards, and that difference has consequences the moment you use a second device.

The core difference

IMAP leaves your mail on the server and shows you a synchronised view of it. Read a message on your phone, and it shows as read on your laptop too, because both are looking at the same copy. Delete it on one, and it disappears from the other, because there was only ever one message to begin with.

POP3 downloads mail to whichever device asks for it first, and depending on how it is configured, often removes it from the server afterwards. The device that checked first gets the message; a second device checking later may find nothing, because there is nothing left to find.

	IMAP	POP3
Where mail lives	On the server, always	Downloaded to one device
Multiple devices	All see the same inbox	Each sees only what it downloaded itself
Read/unread status	Synced everywhere	Tracked separately per device
Folders	Synced, including ones you create	Not synced — local to the device
Offline access	Whatever has already synced	Everything downloaded, since it is stored locally
Server storage used	Mail counts toward the mailbox quota until you delete it	Can be freed once downloaded, if configured to remove it
Standard port	993 (encrypted)	995 (encrypted)

Why IMAP is the right default now

Almost everybody checks email from more than one device — a phone, a laptop, sometimes a tablet or a work computer as well. IMAP is built for exactly that: every device is a window onto the same mailbox, so there is nothing to keep in sync manually and nothing that can go missing because it was downloaded somewhere else first.

This is why every mail app defaults to suggesting IMAP for a new account, and why setting up email on your domain and the client-specific guides linked from it all recommend it as the standard choice.

Where POP3 still gets used

POP3 is not obsolete, just narrower in what it is good for. A few situations still call for it:

A single device, permanently. If you only ever check one specific mailbox from one specific computer and want every message kept locally on that machine regardless of what happens to the server account, POP3 does that by design.
Deliberately archiving off the server. Some people configure POP3 to remove mail from the server after download as a way of keeping a mailbox's storage usage low, accepting that older mail then only exists on the device that downloaded it.
Pulling mail into a second system. Gmail's "check mail from other accounts" feature, for instance, uses POP3 to pull messages from another mailbox into Gmail's own inbox — see sending and receiving domain email in Gmail — which is a reasonable use even though IMAP remains the better everyday choice for a primary mail app.

The most common POP3 mistake

Leaving "remove mail from server after downloading" switched on, then adding a second device later and finding its inbox is empty. The mail was not lost — it was downloaded to the first device and removed from the server exactly as instructed. If you must use POP3 with more than one device, tick the option to leave a copy on the server, though at that point IMAP is doing the same job with less to configure.

What changing protocol involves

You cannot switch an existing account between IMAP and POP3 by flipping a setting — most mail apps require the account to be removed and re-added under the new protocol, since the two work fundamentally differently under the hood. Removing an IMAP account does not delete anything from the server, because the server copy was always the real one; removing a POP3 account may leave you with only whatever had already downloaded, depending on that account's settings.

Not sure which one an existing account uses?

Check the account's settings inside your mail app — the protocol is usually shown on the same screen as the server hostnames. If read status and folders match across your devices, it is almost certainly IMAP; if each device shows a different set of messages, it is POP3.

The ports, if you are configuring manually

Both protocols have an encrypted and an unencrypted port. Always use the encrypted one — the unencrypted versions send your password in plain text and should not be selected in a modern mail app.

Protocol	Encrypted port	Unencrypted (avoid)
IMAP	993	143
POP3	995	110

What this means for storage

Because IMAP keeps everything on the server rather than downloading it off, mail sent and received over IMAP counts continuously toward the mailbox's storage allowance until it is actively deleted — see what a mailbox quota is. POP3, configured to remove mail from the server after download, keeps server storage low by design, since the mail effectively moves to wherever it was downloaded rather than accumulating centrally. This is a genuine trade-off: IMAP's convenience of a synced, searchable, always-available mailbox comes at the cost of needing enough server storage to hold it.

What happens when you add a second device later

This is where the difference becomes concrete rather than theoretical. Add a second device to an IMAP account and it immediately shows the complete existing mailbox, exactly as the first device sees it — nothing to configure beyond entering the account details. Add a second device to a POP3 account configured to remove mail after download, and it shows only whatever arrives from that point onward; everything already collected by the first device is, from the new device's perspective, simply never going to appear.

This is the scenario behind almost every "my old emails are missing" report

Someone sets up a mailbox on a computer using POP3, uses it for months, then adds the same address to a phone and finds the phone's inbox starts empty. Nothing was lost — the mail is still on the original computer — but it was never on the server to begin with by the time the second device asked for it. Switching that account to IMAP from the start avoids this entirely.

The short version

Choose IMAP unless you have a specific reason not to — the two situations above are the only ones that genuinely favour POP3, and neither applies to most people setting up a mailbox for the first time. Every setup guide on this site, for Outlook, iPhone, Android and Apple Mail, defaults to it for exactly this reason.