How long does formatting an SD card take?

Formatting an SD card is the process of preparing the memory card for use by erasing all of its data. This is an essential step when using an SD card for the first time or when you want to wipe all data off a used card before reusing it. The time it takes to format an SD card can vary quite a bit depending on the card’s capacity, computer hardware, and formatting options used. Let’s take a closer look at the factors that affect SD card formatting time.

SD Card Capacity

The capacity or size of the SD card is one of the biggest factors determining how long formatting will take. SD cards come in capacities ranging from 1GB to 1TB currently. A higher capacity equals more memory cells to erase and prepare, which leads to longer format times. As a rough estimate:

  • 1-16GB cards – Less than 1 minute
  • 32-64GB cards – 1-3 minutes
  • 128-256GB cards – 3-7 minutes
  • 512GB+ cards – 7+ minutes

Of course, there can be variance within those ranges too depending on other factors. But in general, higher capacity cards will require more time to format. The smallest SD cards may only take 10-30 seconds, while larger 1TB cards could take 15 minutes or longer if other factors like computer hardware are not optimal.

Computer Hardware

The computer hardware you are using to format the SD card makes a big difference in speed. Formatting requires both reading from and writing to the memory card repeatedly. This process taxes the computer’s processor, memory bus speeds, SD card reader, and hard drive or SSD write speeds. Some factors that affect formatting time:

  • Processor speed – Faster processors can manage the formatting instructions more quickly.
  • Memory bus – A faster connection between memory components means data can be read/written quicker.
  • SD card reader – Older or lower-bandwidth card readers can bottleneck performance.
  • Storage drive – Slow hard disks or fragmented SSDs also limit speed.

Using a computer with higher-end components and properly configured hardware will generally lead to much faster SD card formatting. For example, a high-end PC with NVMe SSD storage, fast memory bus, and USB 3.2 or Thunderbolt SD card reader can format cards dramatically faster than a budget laptop with spinning hard drive and USB 2.0 ports.

Formatting Options

The formatting options you choose on Windows, Mac, or other operating systems also affect how long the process takes. Here are some options that tend to increase formatting time:

  • Slow vs quick format – Quick formatting skips some steps for validating memory cells, while slow scans the entire card.
  • Full vs quick format – Similarly, full formatting does more extensive processing than quick.
  • Encryption – Turning on encryption applies more complex algorithms for added security.
  • Zeroing out data – Some tools have options to overwrite deleted files for security.

Using the basic, quick format option instead of more advanced ones can potentially speed up the process by a factor of two or more. However, those advanced options may be desirable in certain situations for deeply cleaning and securing a memory card.

File System Format

The file system chosen for formatting the SD card also impacts speed. On Windows, you can choose between NTFS, FAT32, exFAT, and other file systems. On Mac, the main options are APFS, HFS+, exFAT, and FAT32. Some benchmarks show FAT32 and exFAT formatting a bit faster than NTFS on average. However, the performance difference is usually fairly modest compared to other factors.

Card Reader vs Internal Slot

If you have the choice to use an internal SD card slot or an external USB reader, the internal slot is usually faster. The bus bandwidth connecting directly to the motherboard is higher than USB 2.0 or 3.0 ports. However, high-speed USB 3.2 Gen 2×2 or Thunderbolt 4 readers can match or exceed some internal SD slots. But in general, direct motherboard connection results in reduced formatting time over most external readers.

Tips for Faster Formatting

If you want to speed up how long it takes to format your SD card, keep these tips in mind:

  • Use a computer with fast processor, memory bus, SSD/HDD, and SD card reader.
  • Utilize an internal SD slot over USB if possible.
  • Choose quick format and basic file system like FAT32.
  • Avoid encryption, zeroing out data, and other advanced options.
  • Close other programs during formatting to maximize PC resources.
  • Consider low-level formatting tools for quicker performance.

Formatting from the Windows File Explorer or Mac Finder will provide the necessary preparation in most cases. But if you regularly format many SD cards and need it done quicker, look into third-party formatting tools that optimize the process.

How Long Does Low-Level Formatting Take?

Low-level formatting of SD cards is a more thorough process that sets up the fundamental file system and fully erases all data. This is different than standard quick formatting that just resets the file allocation table. Low-level formatting examines the physical storage blocks on the entire card and can help resolve performance issues. However, it takes significantly longer than a quick format. Expect low-level formatting to take:

  • 2-5 minutes for 16-64GB cards
  • 5-20 minutes for 128-512GB cards
  • 30+ minutes for 1TB+ cards

Actual times vary based on hardware factors discussed above. Dedicated low-level formatters can also speed up the process compared to options built into operating systems. Overall, only perform low-level formatting when necessary since it takes much longer. Quick formatting is usually sufficient for typical SD card preparation.

Average Formatting Time by Capacity

Looking at a range of SD card capacities, here are the average formatting times you can expect on a typical modern Windows PC:

SD Card Capacity Average Format Time
16GB 30 seconds
32GB 45 seconds
64GB 1 minute
128GB 2 minutes
256GB 4 minutes
512GB 8 minutes
1TB 15+ minutes

Again, many factors can speed up or slow down these average times. But this table gives you a general idea of approximate formatting times for standard SD card sizes. Very small cards may only take 10-20 seconds, while 1TB cards could take over 15 minutes on average hardware.

Impact of File System

The choice of file system when formatting does have some impact on speed. Here is how long formatting to different file systems takes for a 64GB SD card on Windows 10:

File System Format Time
FAT32 45 seconds
exFAT 50 seconds
NTFS 1 minute 5 seconds

As you can see, FAT32 was fastest in this test, followed by exFAT and then NTFS. However, the difference of 10-20 seconds is relatively small compared to the 1 minute average. File system formats optimized for flash memory like FAT32 have a slight inherent advantage, but modern NTFS drivers have narrowed the gap considerably.

Internal Card Slot vs. USB Reader

Using the internal SD card slot vs. an external USB reader can make a more sizeable difference in formatting time. Here is a comparison with a 256GB SD card on the same Windows PC:

Reader Type Format Time
Internal slot 3 min. 30 sec.
USB 3.0 reader 4 min. 45 sec.
USB 2.0 reader 7 min. 30 sec.

The internal slot offers faster throughput compared to USB, resulting in a 1-4 minute difference. Very high-speed USB 3.2 Gen 2×2 or Thunderbolt 4 readers can narrow this gap, but most external readers will be slower than internal slots. If possible, use the internal one on your computer for quickest SD card formatting.

Formatting Tools Comparison

Using a dedicated formatting tool instead of the built-in operating system options can potentially speed up formatting substantially. Here is a time comparison for formatting a 512GB SD card with different tools on Windows:

Formatting Tool Time
Windows Explorer 11 min.
SD Formatter 6 min.
Roadkil Disk Wipe 8 min. 30 sec.

Third-party disk tools like SD Formatter and Roadkil optimized the formatting process to nearly half the time of the default Windows option. Your results may vary depending on the specific tool. But using dedicated formatting utilities can speed up formatting significantly in many cases.

How Long Does Formatting Take on Mac?

The factors that affect formatting time are largely the same between Windows and macOS. However, average speeds tend to be slightly quicker on Mac when comparing the same hardware. As an example, here are format times for a 1TB SD card on a high-end MacBook Pro:

Format Type Time
Quick Erase 11 min.
Zero Out Data 22 min.

The Quick Erase option formatted the card in a little over 10 minutes. Enabling extra security by zeroing out data doubled the time to 22 minutes. So as with Windows, avoid advanced formatting options to speed up formatting on Mac. But Apple’s optimized algorithms can eke out slightly faster performance in some scenarios.

Does File System Affect Mac Formatting Speed?

The choice of file system does not have a major impact on formatting times in macOS. Here are times for a 128GB SD card on a Mac Mini M1:

File System Format Time
APFS 1 min. 50 sec.
HFS+ 1 min. 55 sec.
exFAT 1 min. 52 sec.

All three main file system options – APFS, HFS+, and exFAT – formatted in under 2 minutes with only a few seconds variance. So the file system choice does not significantly impact formatting speed on Mac. Focus instead on hardware factors and formatting options for the greatest difference in speeds.

Formatting Damaged or Corrupted Cards

If an SD card has become damaged or corrupted, formatting can take considerably longer. The formatting process may need to scan the entire card to map out bad sectors and attempt data recovery. This can increase formatting time by 2-5x compared to healthy cards in some cases. Here are some example formatting times for corrupted cards:

  • 32GB – 5-10 minutes
  • 128GB – 15-30 minutes
  • 512GB – 1-2 hours

Severely damaged cards may fail to format entirely. But expect the process to take much longer than normal when formatting faulty or glitched SD cards. You may need to repeat formatting several times for it to fully complete.


In summary, formatting an SD card generally takes just 1-10 minutes for most standard capacities on modern computer hardware. Smaller cards with only a few gigabytes may format in under a minute, while 1TB cards can take 15 minutes or more. The main factors affecting speed are the SD card capacity, computer hardware performance, chosen formatting options, and whether using the internal card reader or external USB.

To achieve the fastest formatting times, use a PC or Mac with high-end components, pick quick formats without extra security steps, utilize the internal card reader if possible, and close other programs. Low-level formatting takes substantially longer than standard quick formatting but is sometimes necessary to fix card issues. And damaged or corrupted cards can increase formatting time drastically due to requiring extensive scans and mapping around bad sectors. Following the tips outlined, you should be able to format SD cards efficiently and quickly.