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About Photo Storage Calculator – Memory Card & Cloud Capacity
The Photo Storage Calculator estimates the total number of photos you can store on an SD card, external hard drive, mobile phone, or cloud storage tier based on average image file size.
Includes configurable reserved space allowances for operating system files, formatting overhead, and application data.
How the calculation works
Usable Storage
Usable Storage (GB) = Total Storage (GB) × (1 - Reserved Space % / 100)
Storage Conversion
Usable Storage (MB) = Usable Storage (GB) × 1,024 (standard binary IEC unit convention)
Photo Count
Estimated Photos = floor(Usable Storage (MB) / Average Photo Size (MB))
How to use this tool
- 1Enter the advertised device or storage card capacity in gigabytes (GB).
- 2Enter the estimated average file size per photograph in megabytes (MB).
- 3Adjust the reserved overhead percentage (default 10% for formatting and system reserve).
- 4Review usable storage in GB, converted MB, and estimated photo capacity.
Understanding the result
Calculations use standard binary conversion (1 GB = 1,024 MB), aligning with how operating systems report storage volume.
RAW camera files are substantially larger (20–80+ MB) than standard JPEGs (3–10 MB) or WebP/HEIC photos (1–4 MB), reducing total capacity accordingly.
The reserved space factor accounts for filesystem tables, formatting structures, and device operating system reserves.
Important limitations
- Actual photo file sizes vary dynamically based on scene complexity, high-ISO sensor noise, color variance, and compression quality.
- Manufacturer packaging uses decimal gigabytes (1 GB = 1,000,000,000 bytes), whereas host devices frequently format cards in binary GiB, creating slight variance.
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Frequently asked questions
Why does my 64 GB SD card show less than 64 GB on my computer?
Drive manufacturers define 1 GB as 1,000,000,000 bytes (decimal), while computer operating systems measure storage in binary gibibytes (1 GiB = 1,073,741,824 bytes). Additionally, filesystem formatting structures take a small percentage of capacity.
How large is an average smartphone photo?
Standard smartphone JPEG photos typically range between 2 MB and 6 MB. High-efficiency HEIC photos range between 1.5 MB and 3 MB, while 48 MP or 108 MP RAW captures can exceed 50 MB to 75 MB per image.
What unit convention is used for MB and GB?
This calculator uses standard binary units (1 GB = 1,024 MB) consistently throughout calculations to match real-world operating system file size reporting.
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