Understanding your result
Storage required uses your average combined file size per photograph. Card capacity rounds down to complete photographs. Required cards round up from that count, so a photograph is never split between cards.
For video recorded on the same media, the Video File Size Calculator estimates storage from bitrate and duration.
The formula
This calculator uses decimal MB and GB consistently. Reserved capacity is removed before counting complete files. Card count is based on photographs per card rather than simply dividing total gigabytes, because small leftover spaces cannot always accommodate another full photograph.
Worked example
Two thousand photographs averaging 25 MB require 50 GB. A 64 GB card with 10% held unused has 57.6 GB available, enough for 2,304 photographs at that average size. One card covers the estimate with 304 positions remaining.
How to use this calculator
- Measure average file size from representative camera files.
- Combine RAW and JPEG sizes if both are saved for every shot.
- Enter actual capacity and a reserve, then compare the required card count.
Measure files from the intended settings
Compressed image sizes vary with scene detail, noise, format, bit depth, and quality settings. A camera’s megapixel count alone does not determine its JPEG or RAW file size. Use representative samples from the same settings, or a documented estimate from the camera manufacturer, and allow room for larger-than-average files.
Capacity labels and backup copies
Storage devices commonly advertise decimal gigabytes while some software displays binary units. A GB is one billion bytes; a GiB is 1,073,741,824 bytes. Enter quantities on the decimal basis used here. The calculation describes one stored copy only. A second card slot recording duplicates, a backup drive, or sidecar files require additional storage planning.
Assumptions & limitations
What this calculation assumes
- Every photograph uses the entered average combined file size.
What to keep in mind
- Actual file sizes and formatted device capacity can vary; no backup redundancy is included.
Common questions
Can I use this for RAW plus JPEG?
Yes. Add the average RAW and JPEG sizes for one exposure and enter the combined MB value.
Why can total free space exceed the next photograph size across several cards?
Free space is separated between devices. The count only uses whole photographs that fit on an individual card.