How the count works

Divide the free space by the size of one item. Both have to be in the same unit, so we turn everything into bytes first. A drive sold as 128 GB holds 128,000,000,000 bytes, because storage makers use the decimal prefixes. One 2 MB photo is 2,000,000 bytes, so 128 GB holds 64,000 of them.

Photo and document sizes vary from file to file, so the per-item sizes are typical values, marked estimate, unless a maker publishes its own (Apple does for ProRAW). For music and video the size follows from the bitrate. A 256 kbps song of 3½ minutes is 256,000 bits per second × 210 seconds ÷ 8 = 6.72 MB. For video we work per hour: 8 Mbps × 3,600 s ÷ 8 = 3.6 GB.

A file system takes a small share of any card or drive (usually well under 1 %). Phones are different: the operating system and apps commonly take 15–40 GB before you store anything. Put that in the "already used" box.

Ready-reckoner tables

Photos per capacity
Format	32 GB	64 GB	128 GB	256 GB	512 GB	1 TB	2 TB
12 MP HEIF estimate	16,000	32,000	64,000	128,000	256,000	500,000	1,000,000
12 MP JPEG estimate	9,142	18,285	36,571	73,142	146,285	285,714	571,428
24 MP JPEG estimate	3,200	6,400	12,800	25,600	51,200	100,000	200,000
24 MP RAW estimate	1,066	2,133	4,266	8,533	17,066	33,333	66,666
ProRAW 12 MP published	1,280	2,560	5,120	10,240	20,480	40,000	80,000
ProRAW 48 MP published	426	853	1,706	3,413	6,826	13,333	26,666

Songs per capacity (3.5-minute songs)
Format	32 GB	64 GB	128 GB	256 GB	512 GB	1 TB	2 TB
128 kbps MP3 computed	9,523	19,047	38,095	76,190	152,380	297,619	595,238
256 kbps AAC computed	4,761	9,523	19,047	38,095	76,190	148,809	297,619
320 kbps computed	3,809	7,619	15,238	30,476	60,952	119,047	238,095
CD FLAC estimate	1,354	2,708	5,417	10,835	21,671	42,328	84,656
Hi-res FLAC estimate	420	840	1,681	3,362	6,725	13,136	26,272

Hours of video per capacity
Format	32 GB	64 GB	128 GB	256 GB	512 GB	1 TB	2 TB
720p published	14 h	28 h	57 h	114 h	228 h	444 h	889 h
1080p published	8.9 h	18 h	36 h	71 h	142 h	278 h	556 h
1080p60 published	5.9 h	12 h	24 h	47 h	95 h	185 h	370 h
1440p published	4.4 h	8.9 h	18 h	36 h	71 h	139 h	278 h
4K published	1.8 h	3.6 h	7.1 h	14 h	28 h	56 h	111 h
4K60 published	1.2 h	2.4 h	4.7 h	9.5 h	19 h	37 h	74 h
iPhone 1080p30 estimate	8.9 h	18 h	36 h	71 h	142 h	278 h	556 h
iPhone 4K30 estimate	3.1 h	6.3 h	13 h	25 h	50 h	98 h	196 h
iPhone 4K60 estimate	1.3 h	2.7 h	5.3 h	11 h	21 h	42 h	83 h

Documents per capacity
Format	32 GB	64 GB	128 GB	256 GB	512 GB	1 TB	2 TB
text document estimate	320,000	640,000	1,280,000	2,560,000	5,120,000	10,000,000	20,000,000
PDF estimate	32,000	64,000	128,000	256,000	512,000	1,000,000	2,000,000
e-book estimate	16,000	32,000	64,000	128,000	256,000	500,000	1,000,000

Other calculators

Download time Any file size at any connection speed, with real-world overhead. GB vs GiB Decimal vs binary units, and why a 1 TB drive shows 931 GB. Video file size File size from bitrate and length, or the bitrate a size allows. Phone storage planner Share out your phone's space between photos, video and music. Cloud backup time How long the first full upload (seeding) takes on your upload speed. Data cap planner How much Netflix, YouTube, Spotify or Zoom fits in a monthly cap. Compression ratio Ratios vs percentages, and a live gzip test on your own text.

How much fits on your storage?

How the count works

Ready-reckoner tables

Worked answers

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