SD vs microSD: Which Memory Card Should You Buy?

2/1/2026 · Storage · 7 min

TL;DR

SD and microSD cards store the same types of data but come in different physical sizes. Choose the form factor your device supports.
For general smartphone use and casual photos, a UHS-I microSD with V30 or A1 rating is a reliable choice.
For 4K video, high frame rate recording, or burst photography pick cards rated V60 or V90 and ideally UHS-II or UHS-III where supported.
For Raspberry Pi, drones, and action cameras prioritize endurance and sustained write speed over peak read speed.

SD cards are the larger standard used in cameras, some laptops, and card readers. microSD cards are physically smaller and used in phones, drones, and many compact devices.
Most SD slots accept full size SD only. Many laptops use microSD via an adapter or built in slot. Adapters let a microSD act as a full size SD card but they do not change speed class.
Check device specifications for supported capacity. Older devices may not support cards above 32 GB or 64 GB without firmware updates.

Read and write speeds matter differently by use case. Read speed helps with file transfers to your computer. Write speed is crucial for recording video and continuous bursts.
Common labels you will see:
Class 10: minimum 10 MB/s write. OK for 1080p video.
UHS-I, UHS-II, UHS-III: bus standards. UHS-II and UHS-III use extra pins for much higher speeds but require compatible devices and readers to reach top speed.
V30, V60, V90: Video speed class indicating minimum sustained write speed in MB/s. V30 = 30 MB/s, V60 = 60 MB/s, V90 = 90 MB/s.
A1, A2: Application performance classes for random read/write IOPS useful when running apps from the card on Android or single board computers.

Card sizes commonly available: 16 GB, 32 GB, 64 GB, 128 GB, 256 GB, 512 GB, 1 TB.
For 1080p video and everyday photos, 64 GB to 128 GB is a good balance. For 4K or long drone sessions choose 256 GB or larger.
Cards larger than 32 GB use exFAT by default. Ensure your device supports exFAT or reformat to a supported filesystem.

Endurance varies by brand and model. Look for cards labeled high endurance or designed for surveillance, dash cams, or continuous recording if you need long term rewrites.
Wear leveling and over provisioning are implemented differently by manufacturers. For mission critical recording, replace cards periodically and keep backups.
Physical durability features include water resistance, temperature tolerance, shock proofing, and X ray resistance. These help in field use but do not guarantee infinite life.

Peak read speed specs are often measured in optimal lab conditions. Real sustained write speed is what affects video recording and burst shooting. Use manufacturer sustained write numbers or independent benchmarks when possible.
Using a UHS-II card in a UHS-I device will usually work but at UHS-I speeds. To get full UHS-II speeds you need a UHS-II compatible camera or a reader and a fast host controller.
Cheap generic cards can lie about capacity and speed. Buy reputable brands from trusted retailers and check serial number verification tools when available.

Smartphone storage expansion and casual photos: microSD UHS-I, Class 10, V30, A1.
Action cameras and drones recording 4K at 60 fps: microSD or SD V60 or V90, preferably UHS-II/III for headroom.
Mirrorless and DSLR continuous burst shooting: SD UHS-II V60 or V90 for fast sustained write to avoid buffer stalls.
Dash cams and surveillance: high endurance microSD, Class 10, V30 or higher depending on resolution.
Raspberry Pi and single board computers: A1 or A2 rated microSD for better random IOPS; if running constant writes choose endurance focused cards.

Use a quality card reader to reach rated speeds when offloading files. Many laptops only have UHS-I slots. A USB 3.1 or USB-C UHS-II reader will give faster transfers on modern hosts.
Avoid using phone USB ports as the primary backup method. They are slower and less reliable than dedicated readers for large transfers.

Confirm device compatibility for capacity and bus speed.
Match video speed class to recording needs: V30 for 1080p, V60 or V90 for high bitrate 4K and high frame rates.
Choose endurance or surveillance lines for continuous write scenarios.
Buy from reputable brands and sellers. Check for warranty and authenticity verification tools.

Choose the card type your device accepts. For most phone and casual camera users a microSD UHS-I Class 10 V30 card is the best value. For professional video, high speed burst photography, or demanding drone work invest in V60 or V90 cards and a UHS-II compatible workflow. For single board computers, prioritize A1 or A2 ratings and endurance. Whatever you choose, pair the card with a good reader and maintain backups to avoid data loss.

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