Memory Card Calculator
Estimate whole photos and encoded video time from decimal card capacity, file size and bitrate with an explicit editable capacity reserve.
Interactive calculator · Method MEMORYCARD-2.2 · Last reviewed: 2026-11-04
Estimate photo and video card capacity
Enter decimal card GB, an explicit reserve percentage, average photo MB and encoded video Mbps. Compare the photo and video alternatives with the same card without reserve.
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
Decimal card GB × (1 − entered reserve/100) gives 115.2 GB. Whole photos and whole recording seconds round downward; these are separate uses of the same capacity. Encoded bitrate determines video time; codec is context only.
How to use the calculator
Enter decimal card GB, average photo MB and measured encoded video Mbps. Choose an explicit capacity reserve from 0% to 95%. The codec choice is retained as context; the entered bitrate controls time.
What the result means
Photo and video counts are alternative uses of the same capacity. The second table row removes only the reserve, keeping card, file size and bitrate identical. Whole recording time never rounds upward; positive durations below one second appear as <1 sec. Tiny nonzero decimal quantities use scientific notation.
Formula and units
Usable GB = card GB × (1 − reserve/100). Whole photos = floor(usable GB × 1000 / average MB). Recording seconds = usable GB × 8000 / encoded Mbps; whole recording time floors seconds. Video minutes divide the unrounded seconds by 60. Reserved GB = card GB − usable GB.
Worked examples
Card size (GB): 128 decimal GB; Average photo file size (MB): 25 MB: Card size (GB): 128 decimal GB; Average photo file size (MB): 25 MB; Video bitrate (Mbps): 100 Mbps; Capacity reserve: 10 %; Codec (context only): H.265.
Example result: Whole photos that fit: 4608; Whole recording time: 2 hr 33 min 36 sec; Video minutes: 153.6 min; Usable recording capacity: 115.2 GB; Entered reserve: 10%; Capacity held in reserve: 12.8 GB.
Card size (GB): 192 decimal GB; Average photo file size (MB): 37.5 MB: Card size (GB): 192 decimal GB; Average photo file size (MB): 37.5 MB; Video bitrate (Mbps): 150 Mbps; Capacity reserve: 10 %; Codec (context only): H.264.
Example result: Whole photos that fit: 4608; Whole recording time: 2 hr 33 min 36 sec; Video minutes: 153.6 min; Usable recording capacity: 172.8 GB; Entered reserve: 10%; Capacity held in reserve: 19.2 GB.
Limitations and common mistakes
Average file size and encoded bitrate are workload assumptions. Actual files, filesystem use, variable bitrate and camera recording limits can differ. The reserve is entered, not measured; it does not establish a spare-card safety margin. Large whole-photo counts are retained as exact integers.
Use decimal MB and Mbps consistently: one byte is eight bits. Do not rescale a measured bitrate again because of the codec, or assume the same card simultaneously holds both full photo and full video estimates.
Sources and assumptions
Unit conversion is mathematical; average file size and encoded bitrate are user-entered workload assumptions.
Method MEMORYCARD-2.2; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.
NIST byte and binary-prefix definitions support the unit conversions.