Best Drives for Time Machine Backup

Apple recommends a backup drive 2–3x the size of your Mac’s internal storage. Time Machine keeps hourly, daily, and weekly snapshots, so the extra room is what lets it hold a useful backup history; when the drive fills, it automatically deletes the oldest snapshots. So a 512 GB MacBook wants at least a 1 TB drive and is happier with 2 TB, and a 1 TB Mac wants 2–3 TB. Because external HDDs give you several times more capacity per dollar than SSDs, sizing up on an HDD is usually cheap insurance against a short backup history.

It depends on where the drive lives. For a desktop Mac with an always-connected backup drive, an external HDD is the better value — you get 4–5 TB for the price of a 1 TB SSD, and Time Machine’s mostly-sequential writes run fine on a hard drive. For a MacBook that needs a backup drive you can throw in a bag, a portable SSD is worth the premium: it is silent, survives being knocked, and finishes the first full backup noticeably faster. Sort the table on this page by price per TB and the trade-off is easy to see.

Time Machine needs APFS (the default on macOS 11 Big Sur and later) or the older Mac OS Extended (HFS+, Journaled). Most external drives ship formatted as exFAT for cross-platform use, so open Disk Utility, select the drive, click Erase, and choose "APFS" — it takes a few seconds. In practice you can usually skip this step: the first time you point Time Machine at a new drive, macOS offers to reformat it for you.

Yes, but partition it first, because Time Machine will otherwise expand to fill the entire drive and leave no room for anything else. In Disk Utility, split the drive into two partitions — one APFS partition dedicated to Time Machine (sized to Apple’s 2–3x rule) and a second partition (exFAT if you also use Windows) for manual files. Keeping them separate stops your backups and your working files from crowding each other out.

Yes. Modern macOS backs up over the network to any SMB share that advertises Time Machine support, which every mainstream NAS (Synology, QNAP, TrueNAS, Unraid) can provide. A NAS is convenient for backing up several Macs to one place and works over Wi‑Fi, but the first full backup is much slower than a direct USB connection and depends on your network staying up. For a single Mac, a directly-attached USB drive is simpler and faster; a NAS makes more sense once you are backing up multiple machines.