How Much Memory Card Capacity Do You Need? 64GB, 128GB, 256GB, 512GB & 1TB by Device

Memory card capacity by device at a glance

These are planning ranges, not universal compatibility rules. Always confirm the card type and maximum supported capacity for your exact device before purchasing.

Capacity, speed, and endurance are different specifications

Before comparing capacities, it helps to separate three memory-card specifications that are easy to confuse.

• Capacity tells you how much data the card can store.
• Speed class indicates a defined minimum writing-performance level. For video recording, ratings such as V30, V60, and V90 help identify whether a card can sustain the write performance required by a recording mode.
• Endurance matters when a device repeatedly writes, deletes, and overwrites data, as dash cams and security cameras commonly do.

A larger card is therefore not automatically a better card. A 1TB card with the wrong performance characteristics may be less suitable for a particular camera than a supported 256GB card with the required speed rating and endurance characteristics.

All of the capacities covered in this guide — 64GB through 1TB — fall within the SDXC capacity range. The SD Association defines SDXC as more than 32GB through 2TB. That does not mean every SDXC-compatible device necessarily supports every capacity within that range.

For video-specific speed ratings, see Top Select's V30 vs V60 vs V90 SD card guide.

How to calculate how much video fits on a memory card

For video, the most important storage number is usually bitrate, not resolution by itself. Two cameras can both record 4K video while producing very different file sizes because their bitrate, codec, frame rate, and compression settings differ.

Video bitrate is usually stated in megabits per second, or Mbps, while card capacity is sold in gigabytes. Because eight bits equal one byte:

MB per second = Mbps ÷ 8

For an approximate hourly storage figure:

GB per hour = Mbps × 0.45

That gives us:

• 4Mbps ≈ 1.8GB per hour
• 10Mbps ≈ 4.5GB per hour
• 25Mbps ≈ 11.25GB per hour
• 60Mbps ≈ 27GB per hour
• 150Mbps ≈ 67.5GB per hour

These are theoretical planning estimates using labelled decimal capacity. Actual recording time can be lower because formatted usable capacity is smaller and real devices may use variable bitrates, audio tracks, metadata, file-system overhead, and other data.

For cameras with multiple simultaneous streams — such as front-and-rear dash cams — add the bitrates of all recording channels before calculating storage use.

How much capacity does a dash cam need?

Dash cams normally use loop recording. Once available card space is exhausted, the camera begins overwriting the oldest unprotected footage. Capacity therefore determines primarily how far back your recording history extends, rather than whether the camera eventually stops recording.

There is no reliable universal number of hours for a 64GB, 128GB, or 256GB dash-cam card because bitrate varies significantly between models, quality settings, codecs, and the number of cameras recording at the same time.

BlackVue's current Elite 9 Series provides a useful manufacturer example. Its single front camera records 4K at bitrates ranging from 10Mbps to 60Mbps depending on the quality setting, while its front-and-rear configuration can reach a combined 85Mbps.

Manufacturer example: BlackVue Elite 9 Series recording-time table. The wide range comes from different bitrate and quality settings and should not be applied directly to unrelated dash-cam models.

Practical dash-cam recommendation

64GB can work when your dash cam supports it and a shorter loop history is acceptable.

128GB is a more flexible starting point for many current single-channel dash cams.

256GB becomes attractive for 4K, front-and-rear recording, longer parking-mode retention, or drivers who want substantially more footage before overwrite.

512GB or 1TB can provide a much longer recording window, but only when the exact dash cam supports that capacity.

Because a dash cam continuously records and overwrites footage, card endurance should be considered alongside capacity. A standard high-speed card and an endurance-focused card are designed around different workloads.

How much capacity does a security camera need?

Security-camera storage depends heavily on whether the camera records continuously or only when an event is detected.

For continuous recording, bitrate gives you a useful estimate of the retention period:

Theoretical continuous-recording estimates calculated from bitrate and labelled capacity. Reolink's own storage guidance also calculates retention from card capacity and recording bitrate. Actual retention varies by camera settings, usable capacity, multiple streams, codec, and recording behaviour.

What about motion-triggered recording?

Motion-triggered recording should not be described using a universal percentage saving. The result depends entirely on how many minutes the camera actually records each day.

A camera watching a busy storefront or street may generate hours of event footage each day, while a camera in a quiet interior could record only a few minutes. Reolink, for example, uses a specific 15-minutes-per-day alarm-recording scenario in one of its planning examples rather than claiming that motion recording always reduces storage by a fixed percentage.

Practical security-camera recommendation

For motion-triggered recording, 64GB–128GB may provide substantial retention when daily event activity is low.

For continuous 24/7 recording, 256GB–512GB is often a more useful starting range, but the correct answer should be calculated from the camera's actual bitrate.

Consider 1TB when the exact camera supports it and you genuinely need the additional retention window.

As with dash cams, continuous surveillance is a repeated-write workload, so endurance matters as much as simply increasing capacity.

Drones and 4K action cameras

High-resolution cameras can consume storage quickly because of their video bitrate. DJI's Mini 4 Pro provides a useful manufacturer example: DJI specifies H.264/H.265 recording with a maximum video bitrate of 150Mbps.

At 150Mbps, the theoretical storage requirement is approximately 67.5GB per hour.

The 150Mbps maximum is manufacturer-documented for the DJI Mini 4 Pro. The recording times above are mathematical estimates at that bitrate, not DJI-published recording-time guarantees. Actual video modes may record below the maximum bitrate.

DJI's current Mini 4 Pro recommended-card list includes examples through 512GB. That should be treated as a recommended-card list, not as proof that DJI has declared 512GB to be the aircraft's absolute capacity ceiling.

Practical drone and action-camera recommendation

128GB–256GB provides a practical balance for many users who can offload footage between shooting sessions.

512GB becomes more useful for long field days, repeated flights, higher-bitrate modes, or situations where transferring footage during the day is inconvenient.

Capacity is only half the decision. Always check the speed rating required by the exact camera and recording mode.

For more detail on video-speed requirements, see Top Select's V30 vs V60 vs V90 guide.

DSLR and mirrorless cameras: how many photos fit?

There is no reliable universal RAW-file size based only on whether a camera is Micro Four Thirds, APS-C, or full-frame. RAW file size is affected by megapixel count, bit depth, compression mode, image content, and manufacturer implementation.

A more accurate method is to use the average file size actually produced by your camera.

Theoretical counts using labelled decimal capacity. Actual available space after formatting is lower, and real image sizes vary from frame to frame.

How to estimate your own camera

Take a representative group of images from your camera and calculate their average size. If 20 RAW files occupy approximately 1GB, for example, the average is about 50MB per image. That makes the middle column above a much more useful estimate than a generic assumption based on sensor size.

For cameras used heavily for video, switch back to bitrate rather than photo file size. The same recording-time formula used earlier in this guide applies.

If burst shooting and card performance matter as much as capacity, see Top Select's UHS-I vs UHS-II guide for sports and wildlife photography.

Nintendo Switch, Nintendo Switch 2, and Steam Deck

Gaming devices need a different calculation because storage demand depends on the size of the software library rather than recording bitrate.

Nintendo Switch, Switch OLED, and Switch Lite

Nintendo officially supports the following card types on the original Nintendo Switch family:

• microSD up to 2GB
• microSDHC from 4GB to 32GB
• microSDXC from 64GB through 2TB

A system update is required to use microSDXC cards. Nintendo also recommends UHS-I-compatible cards with transfer speeds of approximately 60–95MB/s for a better gameplay experience.

For users who buy a meaningful amount of downloadable software, 128GB–256GB is a sensible starting range. Larger digital libraries can justify 512GB or 1TB while remaining within Nintendo's officially stated 2TB microSDXC limit.

Nintendo Switch 2

Nintendo Switch 2 changes the storage requirement completely. It uses microSD Express for expandable storage rather than an ordinary microSD card.

Nintendo officially supports microSD Express cards up to 2TB. A system update through the internet is required the first time a microSD Express card is used.

Switch 2 includes 256GB of internal storage, with part of that capacity reserved for the system. A 256GB microSD Express card therefore acts as additional storage rather than being required immediately for every owner.

256GB–512GB is a reasonable expansion range for moderate digital libraries. 1TB becomes more attractive for users who want a large amount of downloadable software installed at once.

Game save data is still stored in system memory and cannot be copied or saved to a microSD Express card.

A standard microSD card previously used with an original Switch cannot be used as normal Switch 2 game storage. Nintendo does, however, allow compatible screenshots and videos from an original Switch microSD card to be imported into Switch 2 system memory.

Steam Deck

Valve specifies a UHS-I microSD slot supporting SD, SDHC, and SDXC cards. Valve also confirms that Steam Deck formats microSD cards as ext4 with casefolding.

Valve's technical specifications identify SDXC compatibility but do not publish a separate maximum-capacity figure in gigabytes. The SDXC standard itself extends through 2TB, but device compatibility should not be inferred from the SDXC standard alone.

For practical use, 256GB–512GB provides useful extra room for part of a PC game library, while 1TB can reduce the need to uninstall and reinstall large games frequently.

Because individual PC game sizes vary enormously, the best method is to total the installed sizes of the games you actually want available at the same time.

Phones and tablets

This category starts with a compatibility check: many current phones and tablets do not include a microSD slot.

Before choosing a card, confirm whether the device:

• has a built-in microSD slot, or
• can access a memory card through a compatible external reader.

For photo and video backup, the simplest capacity calculation is often based on the library you already have.

If your current camera roll occupies 90GB, for example, a 128GB card leaves relatively little room for future growth. A 256GB card provides substantially more headroom.

For users who regularly record high-bitrate video, estimate future storage from the recording bitrate rather than relying on a generic statement such as "X hours of 4K." Different phones can use very different bitrates for 4K recording.

Why does a memory card show less usable space than the label?

Storage manufacturers normally advertise capacity using decimal units:

1GB = 1,000,000,000 bytes

A 128GB card therefore contains approximately 128 billion bytes before accounting for formatting and other reserved space.

If those 128 billion bytes are instead expressed in binary gibibytes:

128GB ≈ 119.2GiB

That does not mean every phone, camera, computer, or operating system will literally display the card as "119GB." Different systems and interfaces can report storage units differently, and formatting also reduces usable space.

One large card or several smaller cards?

There are legitimate arguments for both approaches.

One large card reduces card swapping and makes long shooting or recording sessions easier to manage.

Several smaller cards distribute your data across multiple pieces of media. If one card is lost, damaged, or corrupted, the entire shoot is not necessarily concentrated on that single card.

For photography, filmmaking, drone work, weddings, field research, and other irreplaceable content, card rotation can therefore be part of a broader risk-management workflow.

For dash cams and security cameras, the priorities are different. Those devices repeatedly overwrite data, so endurance, compatibility, and the desired retention window usually matter more than splitting storage among several cards.

No memory card should be treated as the only permanent copy of irreplaceable data.

64GB vs 128GB vs 256GB vs 512GB vs 1TB

64GB: good for lighter workloads

64GB is best suited to lighter workloads, shorter recording windows, casual photography, or situations where files are transferred frequently.

For high-bitrate video or multi-camera recording, however, 64GB can fill much faster than expected.

128GB: a strong general starting point

128GB is a useful entry point for many current workloads. It provides considerably more breathing room for dash cams, event-triggered security cameras, photography, drones, and smaller digital game libraries without immediately moving into very large capacities.

256GB: the practical middle ground

256GB is a strong option for users who record more video, use dual-camera systems, shoot substantial amounts of RAW photography, or maintain larger digital libraries.

For many users, this is where capacity starts becoming noticeably more convenient rather than merely adequate.

512GB: for heavier recording and larger libraries

512GB becomes useful for longer continuous-recording retention, extended 4K workflows, high-volume photography, and larger gaming libraries.

At this tier, checking exact device compatibility becomes especially important rather than assuming that every device accepting SDXC or microSDXC has been validated for 512GB.

1TB: useful when the workload actually needs it

1TB is not inherently excessive. It can make sense for large digital game libraries, long high-bitrate video sessions, extensive RAW photography, or supported continuous-recording systems.

For lighter photography, short dash-cam loops, or footage that is transferred frequently, 1TB may provide little practical advantage over 128GB or 256GB.

Maximum supported capacity: what is actually confirmed?

Do not infer host-device compatibility from the SDXC standard alone. A memory card can comply with the SDXC standard while still exceeding what a particular camera, recorder, or other device has been validated to use.

Final recommendation

Do not choose memory-card capacity based only on resolution or on the largest capacity available.

Start with the workload:

• For video: find the device's actual bitrate. If several cameras record simultaneously, add their bitrates together.
• For photography: measure the average size of files produced by your actual camera.
• For security cameras: determine whether recording is continuous or event-triggered and calculate the retention period you actually need.
• For Nintendo Switch, Switch 2, and Steam Deck: total the software you genuinely want installed at the same time.
• For phones and tablets: look at the size of your existing media library and leave room for future growth.

Then check three separate requirements before purchasing:

capacity compatibility + speed requirement + workload/endurance requirement.

For many everyday applications, 128GB–256GB remains a useful starting range.

Move to 512GB when longer retention, heavier 4K recording, high-volume photography, or a larger gaming library genuinely requires it.

Choose 1TB when the device specifically supports it and your workload makes the additional capacity useful.

FAQ

Is 128GB enough for a dash cam?

It can be, but there is no universal number of recording hours for a 128GB card. Bitrate, quality setting, codec, and the number of camera channels determine retention. For example, BlackVue's Elite 9 recording table gives approximately 4 hours 10 minutes to 23 hours for a 128GB card in its single-channel 4K modes, depending on quality. Its front-and-rear configuration provides approximately 2 hours 50 minutes to 11 hours 25 minutes. Check the recording-time table or bitrate published for your exact dash cam.

How much storage do I need for 24/7 security-camera recording?

Calculate it from the camera's actual bitrate. At a constant 4Mbps, for example, 128GB provides roughly 3 theoretical days, 256GB roughly 6 days, and 512GB roughly 12 days of continuous recording before other overhead is considered. Higher bitrates reduce retention significantly. Always confirm the maximum card capacity supported by the camera.

Does Nintendo Switch support a 1TB microSD card?

Yes. Nintendo officially supports microSDXC cards from 64GB through 2TB on Nintendo Switch, Nintendo Switch Lite, and Nintendo Switch OLED. A system update is required to use microSDXC cards.

Does Nintendo Switch 2 use the same memory cards as the original Switch?

No. Nintendo Switch 2 requires microSD Express for normal expandable storage and officially supports microSD Express cards up to 2TB. A standard microSD card from an original Switch cannot be used to store or load Switch 2 downloadable software, although compatible screenshots and videos from an older Switch card can be imported.

Are Nintendo Switch 2 save files stored on the microSD Express card?

No. Nintendo states that game save data is stored in Nintendo Switch 2 system memory and cannot be copied or saved to a microSD Express card. The card can store downloadable software, update data, DLC, screenshots, and video captures.

What size microSD card should I use for Steam Deck?

There is no single required capacity. Valve specifies UHS-I support for SD, SDHC, and SDXC cards. A 256GB or 512GB card provides useful extra game storage for many users, while 1TB can make sense for larger installed libraries. Valve identifies SDXC compatibility but does not separately publish a maximum supported capacity in gigabytes.

How much 4K video fits on 128GB?

"4K" alone is not enough information because bitrate can vary substantially between devices and recording modes. At 60Mbps, 128GB provides roughly 4.7 theoretical hours. At 100Mbps, it provides about 2.8 hours. At 150Mbps, it provides about 1.9 hours. Actual recording time varies with usable capacity, variable bitrate, audio, metadata, and device behaviour.

Is 1TB overkill for a memory card?

Sometimes, but not always. 1TB can be useful for large digital-game libraries, long high-bitrate video sessions, extensive RAW photography, or supported continuous-recording systems. For lighter workloads or files that are offloaded frequently, 128GB–256GB may provide the same practical experience for less money.

Why does a 128GB memory card sometimes show around 119GB?

Manufacturers label storage using decimal units, where 128GB represents approximately 128 billion bytes. Expressed in binary gibibytes, that amount is about 119.2GiB. However, different operating systems report storage differently, so not every device will literally display "119GB." Formatting also reduces usable capacity.

Is one large memory card better than several smaller cards?

A large card means fewer swaps and longer uninterrupted recording. Several smaller cards distribute your data across multiple pieces of media, limiting how much material is concentrated on one card. For irreplaceable photos or footage, card rotation combined with regular backups can reduce the consequences of losing or damaging one card.

Does a larger memory card make a camera faster?

No. Capacity and performance are separate specifications. Moving from 128GB to 512GB does not automatically improve write speed, burst performance, or video compatibility. Check the card's speed ratings and your camera's requirements separately from capacity.