Storage Capacity Calculator
Work out how many photos, hours of video or songs fit on any drive, card or phone - with the file size or bitrate each answer assumes.
Storage Calculator
The figure on the box, which is counted in decimal
An operating system takes its share before you store anything
phone photos in HEIC
46,800
Advertised
128 GB
Decimal, as sold
Your system shows
119.2 GB
Binary, the same bytes
Free to use
109.0 GB
After ~11 GB of system
Share you get
91%
How many photographs, by format
- Phone HEIC, 12 MP - 2.5 MB each46,800
- Phone JPEG, 12 MP - 3.5 MB each33,428
- Camera JPEG, 24 MP - 9 MB each13,000
- Camera RAW, 24 MP - 28 MB each4,178
- Camera RAW, 45 MP - 55 MB each2,127
- ProRAW, 48 MP - 75 MB each1,560
Photographs vary more with subject than with any setting - a plain sky compresses to a fraction of a crowded street - so these are mid-range figures for an everyday shot rather than a maximum.
Where these figures come from
- Phone HEIC, 12 MP — The iPhone default since iOS 11
- Phone JPEG, 12 MP — Roughly 40% larger than the same shot as HEIC
- Camera JPEG, 24 MP — Fine quality, in-camera processing
- Camera RAW, 24 MP — Uncompressed sensor data, roughly 3x the JPEG
- Camera RAW, 45 MP — Full-frame high-resolution camera bodies
- ProRAW, 48 MP — iPhone Pro, and the reason phone storage fills
The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.
How the storage calculation works
Ask how many photos fit on 128 GB and you will get answers between 15,000 and 37,000. Ask how many hours of 4K video fit on a terabyte and the published range runs from ten hours to over a hundred.
Both ranges are correct. They differ because the answer depends entirely on file size for photographs and bitrate for video, and almost none of those pages say which they assumed.
files = usable bytes ÷ size of one file
hours of video = (usable bytes × 8) ÷ (bitrate in Mbps × 1,000,000 × 3,600)
That second formula reduces to a useful shortcut: on one decimal terabyte, hours = 2,222 ÷ bitrate in Mbps. At 20 Mbps that is 111 hours; at 100 Mbps it is 22; at ProRes rates it is under four.
Three capacities, not one
A drive advertised as 128 GB gives you three different numbers, and the gap between them is where most of the confusion lives.
| Figure | Why | |
|---|---|---|
| Advertised | 128 GB | 128,000,000,000 bytes, counted in decimal |
| Your system shows | 119 GB | The same bytes divided by 1,024 three times |
| Free to use | ~109 GB | After the operating system takes its share |
The MB to GB converter and GB to TB converter handle the first two rows directly, and why your drive shows less space than advertised covers the arithmetic in full.
Nothing has gone missing between the first row and the second — it is one quantity in two units. The third row is a real loss, and on a phone it is 10 to 15 GB before you take a single photograph.
Why photo counts vary so much
| Format | Typical size | On 128 GB (after iOS) |
|---|---|---|
| Phone HEIC, 12 MP | 2.5 MB | ~46,800 |
| Phone JPEG, 12 MP | 3.5 MB | ~33,400 |
| Camera JPEG, 24 MP | 9 MB | ~13,000 |
| Camera RAW, 24 MP | 28 MB | ~4,170 |
| ProRAW, 48 MP | 75 MB | ~1,560 |
HEIC holds thirty times what ProRAW does on the same phone, which is why one person says 40,000 and another says 1,500 and both are telling the truth.
Photographs also vary with subject rather than with any setting. A plain sky compresses to a fraction of a crowded street at identical resolution, so treat these as mid-range rather than exact.
Video is bitrate, not resolution
The common mistake is thinking "4K" is a size. It is a resolution; the size comes from the data rate, and the same 4K footage can be 16 Mbps or 707.
| Source | Bitrate | Hours on 1 TB |
|---|---|---|
| Phone 1080p, 30 fps | 8.7 Mbps | ~255 |
| Streamed 4K | 16 Mbps | ~139 |
| Phone 4K, 30 fps | 22.7 Mbps | ~98 |
| Phone 4K, 60 fps | 58.7 Mbps | ~38 |
| Action camera 4K, 60 fps | 100 Mbps | ~22 |
| ProRes 422 HQ 4K | 707 Mbps | ~3 |
The phone figures come from the capture sizes Apple publishes — 170 MB a minute for 4K at 30 fps, 440 for 60. The disc and codec rates are the formats' own specifications.
This is also why a downloaded film is far smaller than footage you shot yourself: a streamed 4K file has been compressed for delivery, and your camera has not compressed anything for anyone.
A planning rule that survives contact
For a shoot, work in gigabytes per hour rather than hours per card — multiply the bitrate in Mbps by 0.45 to get GB per hour, close enough for packing decisions. Phone 4K at 30 fps is about 10 GB an hour; an action camera at 100 Mbps is 45.
Then double it. Cards fill faster than planned, and the footage has to live somewhere else afterwards.
Frequently asked questions
How many photos fit on 128GB?
Around 46,800 phone photos in HEIC, or 33,400 as JPEG, once iOS has taken its share. A camera shooting 24 MP RAW fits about 4,170, and an iPhone shooting 48 MP ProRAW only about 1,560. The format matters roughly thirty times more than the capacity does, which is why published answers to this question vary so widely.
How many hours of 4K video fit on 1TB?
About 98 hours of phone 4K at 30 fps, 38 at 60 fps, 22 from an action camera at 100 Mbps, and under four in ProRes. "4K" describes resolution rather than file size - the bitrate decides it, and the same resolution spans a range of roughly eighty to one.
Why does my 1TB drive show as 931GB?
The manufacturer counts a terabyte as a million million bytes, while Windows divides by 1,024 three times and labels the result GB when it means GiB. Both describe the same drive. Nothing is missing, and macOS and Linux report the decimal figure that matches the box.
How much storage does an hour of recording take?
Multiply the bitrate in Mbps by about 0.45 for gigabytes per hour. Phone 4K at 30 fps is roughly 10 GB an hour, 4K at 60 fps is 26, and an action camera at 100 Mbps is 45. For a shoot, work out the hours you need and then double the card capacity - footage has to be offloaded somewhere afterwards.
How much space does the operating system take?
Roughly 11 GB on an iPhone, 15 on an Android phone and 35 on a Windows laptop including the recovery partition, though all three move with every update. On a 128 GB phone that is the difference between the 119 GB the system reports and the 109 GB you can actually fill.
Is a 256GB phone twice as useful as a 128GB one?
More than twice, because the operating system takes its share only once. A 128 GB iPhone leaves about 109 GB free and a 256 GB one about 228 - so the larger phone gives you 2.1 times the usable space, not 2.0. The gap widens the smaller the phone, which is why 64 GB models aged so badly.
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