SanDisk Ultra microSD 100MBs 256GB

SanDisk Ultra microSD UHS-I 256GB – SDSQUAR-256G

The SanDisk Ultra microSD UHS-I 256GB is a microSDXC memory card built for everyday storage expansion on Android smartphones, tablets, dashcams, and compact cameras. Operating on the UHS-I bus interface, the SDSQUAR-256G delivers sequential read speeds of up to 100MB/s — sufficient to transfer approximately 1,000 photos in under a minute when paired with a USB 3.0 card reader.

At 256GB, this card doubles the storage headroom of the 128GB variant, making it a practical choice for users who shoot large volumes of Full HD video, store media libraries, or run multiple apps directly from external storage. The SDSQUAR-256G carries an A1 Application Performance Class rating, mandating a minimum of 1,500 read IOPS and 500 write IOPS — the threshold required for responsive app loading from a microSD card on Android devices.

Speed Class and Bus Interface

The SanDisk Ultra 256GB is rated UHS Speed Class U1 and Speed Class 10, both of which guarantee a minimum sustained write speed of 10MB/s. This rating is sufficient for continuous Full HD (1920×1080) video recording. However, it does not meet the V30/U3 threshold required for 4K UHD capture. Users with 4K recording requirements should consider the SanDisk Extreme line instead.

The card operates on the UHS-I single-row bus, with a theoretical ceiling of 104MB/s. The stated 100MB/s read speed places the SDSQUAR-256G at near-maximum utilisation of this interface. Write speeds are not published by SanDisk for this model. Third-party benchmarks on the 256GB Ultra consistently record sequential write performance between 40MB/s and 65MB/s under controlled test conditions, which is consistent with the TLC NAND flash used across the Ultra range.

Storage Capacity and File System

The SDSQUAR-256G uses the microSDXC format, formatted to exFAT by default. The exFAT file system removes the 4GB single-file size limit imposed by FAT32, which is relevant for users recording long uninterrupted video clips. At 256GB, the card can hold approximately 20,000 hours of Full HD video, depending on the codec and bitrate of the recording device.

Actual usable capacity falls slightly below the labelled 256GB, as the manufacturer calculates storage using 1GB = 1,000,000,000 bytes, while operating systems use binary units (1GiB = 1,073,741,824 bytes).

Build and Environmental Ratings

The SanDisk Ultra microSD 256GB is certified across four environmental protection categories:

• Waterproof — resistant to water immersion
• Temperature proof — operating range of -25°C to 85°C (-13°F to 185°F)
• Shockproof — resistant to drops and physical impact
• X-ray proof — data integrity maintained through airport security X-ray scanners

Storage temperature extends to -40°C to 85°C (-40°F to 185°F), covering cold-climate storage and vehicle glove box conditions in tropical climates.

Physical dimensions are 14.99mm (L) × 10.92mm (W) × 1.02mm (H), consistent with the standard microSD form factor.

Included Adapter and Companion App

The SDSQUAR-256G ships with a microSD-to-SD adapter, enabling use in full-sized SD card slots on DSLR cameras, mirrorless cameras, and laptops. The adapter is backward compatible with SDHC and SDXC-capable host devices.

SanDisk also provides the SanDisk Memory Zone app, available free on Google Play. The app consolidates file management across internal storage and the microSD card from a single interface and supports automatic file migration to the card when the device’s internal storage runs low — a practical feature for 256GB card users managing large media libraries.

Compatibility

The SDSQUAR-256G is compatible with any microSDHC or microSDXC supporting host device, including:

• Android smartphones and tablets with adoptable or portable storage support
• Dashcams recording in Full HD
• Chromebook devices (certified Works with Chromebook)
• Compact cameras and action cameras rated for Class 10 / U1
• Nintendo Switch and Nintendo Switch Lite (via adapter)

Devices produced before the SDXC standard (pre-2008) may not support this card and should be verified with the manufacturer before purchase.