How to choose a microSD card for cameras, drones, and handhelds
Match microSD capacity, Video Speed Class, A1 or A2 ratings, endurance, and device compatibility without paying for specifications the host cannot use.
1. The device manual sets the boundary
A microSD card can carry many logos, but the host decides which capacities, file systems, bus modes, and features are usable. Check the product manual or support page before shopping, especially for drones, action cameras, security cameras, game systems, and older phones.
SDHC covers capacities above 2GB through 32GB. SDXC covers capacities above 32GB through 2TB. A device designed only for SDHC may not recognize a larger SDXC card even if it physically fits.
2. Use Video Speed Class for recording
Video Speed Class communicates sustained sequential write performance. V30 represents an assured 30 MB/s under the standard's conditions; V60 and V90 represent 60 and 90 MB/s. Always follow the device requirement instead of relying on broad packaging claims.
A card's large advertised read-speed number describes fast transfers under compatible conditions, not necessarily the sustained write behavior needed for recording.
3. A1 and A2 are for application workloads
Application Performance Class adds minimum random-access requirements for devices that run applications or manage many small files from the card. A1 and A2 are not replacements for Video Speed Class; they describe a different workload.
A2 raises the random-performance targets and uses host features such as command queuing and cache. The host must support those features to realize the intended advantage. For cameras that primarily write video streams, the required V rating usually matters more than A1 versus A2.
4. Continuous recording favors endurance
Dash cameras, security cameras, and other looping recorders repeatedly overwrite the card. Products sold specifically as high-endurance or industrial media are designed for that use and are often a wiser choice than a faster consumer card with no continuous-recording positioning.
Capacity affects how often the device overwrites old footage, but retention also depends on bitrate, number of streams, and recording schedule. Check the recorder's supported maximum before buying the largest card.
5. Protect yourself from counterfeit capacity
Tiny, high-capacity cards are frequent counterfeit targets. Buy from a known retailer or authorized seller, inspect the packaging, and test the full reported capacity before trusting the card with important footage. A quick transfer test is not enough if it writes only a small part of the card.
Format the card in the destination device, keep firmware current, and replace cards that produce recording errors. When the footage matters, rotate cards and copy it promptly.
Frequently asked questions
Is A2 always faster than A1?
A2 has higher standardized random-performance targets, but the host needs to support A2 features. It does not automatically improve sustained video recording.
Can I use a microSD card in an SD adapter?
Usually, if the device supports the card's capacity and speed requirements. The adapter changes the physical format; it does not make the card faster.
What matters most for a dash camera?
Device compatibility and a card designed for high-endurance, continuous recording generally matter more than the highest advertised read speed.
Primary references
Technical standards can change. We use the relevant standards organizations as primary references and recommend checking the device maker's current manual.