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A 128GB SD card can record anywhere from a few hours to well over 10 hours of video, depending mainly on the camera’s bitrate and recording mode. At 100 Mbps, manufacturer estimates range from about 2 hours 45 minutes to 170 minutes; at lower bitrates, the same card lasts much longer. For a useful estimate, check the camera’s exact setting—not just whether it records in 4K.
Why recording time varies
A camera writes video at a particular bitrate: the amount of data recorded each second. Higher bitrates use more storage, so a 128GB card fills sooner. Resolution alone does not determine recording time; two 4K modes can use different bitrates, and a Full HD mode can also vary by camera and setting.
Manufacturer capacity tables are estimates, not guarantees. Sony notes that recording time varies with shooting conditions and card type, while Panasonic warns that certain recording modes can reduce the available time. The camera’s remaining-time display and the manual for the specific model are the most relevant checks.
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Examples from camera makers
These figures apply to the stated manufacturer tables and modes; they should not be treated as a universal promise for every camera or card.
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| Source and scope | Recording setting | Estimated time on 128GB |
|---|---|---|
| Panasonic DC-BS1H manual, specified MP4 modes at 59.94Hz or 50Hz | 100 Mbps | About 2 hours 45 minutes |
| Panasonic DC-BS1H manual, specified Full HD MP4 mode | 28 Mbps | About 9 hours 45 minutes |
| Panasonic DC-BS1H manual, specified Full HD MP4 mode | 20 Mbps | About 13 hours |
| Fujifilm general bitrate and media-capacity guide, updated May 28, 2026 | 100 Mbps | About 170 minutes |
| Fujifilm general bitrate and media-capacity guide, updated May 28, 2026 | 50 Mbps | About 340 minutes |
| Sony FDR-X3000 XAVC S table, depending on listed mode | 100 Mbps | About 155 minutes |
| Sony listed XAVC S mode | 60 Mbps | About 255 minutes |
| Sony listed XAVC S HD mode | 50 Mbps | About 310 minutes |
The variation at 100 Mbps illustrates why one headline duration can mislead: manufacturers may use different recording formats, settings, rounding, and assumptions about usable capacity. Consult the camera manual for its own estimate. Fujifilm’s recording-time guide; Panasonic DC-BS1H manual; Sony recording-time guide.
Estimate time from bitrate
For a rough estimate using decimal card capacity, divide the card’s total bits by the recording bitrate and convert seconds to hours:
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Approximate hours = (128 × 8 × 1,000) ÷ (bitrate in Mbps × 3,600)
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- Great choice for compact to mid-range point-and-shoot cameras
- Quick transfer speeds up to 140MB/s (Up to 140MB/s read speed engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, requires compatible devices capable of reaching such speeds. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes.)
- Up to 128GB to store tons of pictures (1GB=1,000,000,000 bytes. Actual user storage less.)
- Exceptional video recording performance with UHS Speed Class 1 (U1) Class 10 rating for Full HD video (1080p) (UHS Speed Class 1 (U1) designates a performance option designed to support real time video recording with UHS enabled host devices. See consumers speed page on SanDisk site. Full HD (1920x1080) video support may vary based upon host device, file attributes, and other factors. Visit the SanDisk Video Knowledge Base for more information.)
- Compatible with SanDisk SD UHS-I card reader (sold separately)
Check card compatibility and speed before buying
Capacity alone does not establish that a card will work for a particular recording mode. Confirm the camera supports the card format and capacity, and check the sustained write-speed requirement for the mode you intend to use. Camera manuals specify these requirements; the reviewed manufacturer guidance does not establish one speed class that suits every camera.
- Check the camera manual’s SD or SDXC compatibility information.
- Look up the required write speed for the specific video mode, particularly for high-bitrate recording.
- Use a genuine, reliable card that meets those requirements; do not assume a card is suitable based only on its capacity or advertised maximum speed.
For examples of the information camera manuals provide, see Sony’s recording-time guidance and the Canon EOS R10 manual.
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- Fast for better pictures and Full HD video. Full HD (1920x1080) video support may vary based upon host device, file attributes, and other factors
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- From 32GB to 256GB(1) to store tons of pictures and even more Full HD video(2). (1)1GB=1,000,000,000 bytes Actual user storage less
- Exceptional video recording performance with UHS Speed Class 1 (U1)(5) and Class 10 rating for Full HD video (1080p)(2). (5)UHS Speed Class 1 (U1) designates a performance option to support real time video recording with UHS enabled host devices
- Quick transfer speeds up to 100MB/s. Up to 100MB/s[64GB-256GB; 90MB/s for 32GB] read speed; write speed lower Based on internal testing; performance may be lower depending on host device, usage conditions, and other factors 1MB=1,000,000 bytes
What to check for 4K recording
There is no single recording-time figure for “4K.” Find the camera’s chosen 4K format and bitrate in its menu or manual, then use the manufacturer’s capacity table or the calculation above. If the manual lists a duration for the exact setting, prefer that over a general estimate because it reflects the camera’s recording modes and assumptions.
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