Storage calculator: how many files fit on a drive

Enter the capacity and the size of one file. The tool tells you how many of them fit.

How it works

The tool converts both sizes to bytes and divides, rounding down to whole files. It uses decimal units (KB, MB, GB, TB are powers of 1000). If you want the binary units (KiB, MiB, GiB, TiB), choose them in the menus.

A realistic way to plan

1. Find a typical file size. Look at the properties of a few of your own files. A phone photo, a song or a one-minute video differ a lot between phones and apps.
2. Use the average, not the smallest.
3. Leave 10 to 20 percent free, because drives slow down when full, and the system needs room.
4. Plan for growth. Storage needs usually grow.

Why the real space is smaller

• Decimal against binary. A "1 TB" drive is 10^12 bytes, shown as about 931 GiB by systems that use powers of 1024.
• Formatting and the file system use some space.
• The system and apps take their share on a phone or a laptop.
• Backups and caches can fill more than you expect.

Examples

A 128 GB phone does not give you 128 GB for photos: after the system and apps there may be around 100 GB or less. A 5 MB photo means about 20,000 photos in 100 GB. A 50 MB, one-minute 4K video means about 2,000 clips.

Common mistakes

1. Using the size of one great file as the average of all.
2. Filling the drive to the last gigabyte.
3. Counting only photos and forgetting that an app's data and the system need room.

This is an independent guide. It is not connected with the IERS, BIPM, IANA, NIST or any company named here. Facts were read on 14 November 2026 from the sources named on each page; calculated values come from Python.