You can use the
fsutil utility that comes with Windows.
fsutil fsinfo ntfsinfo c:
In the output, look for the
Mft Valid Data Length line. The value is hexadecimal; you can convert it to decimal using the Windows calculator or by simply running it (starting with
0x) in PowerShell as a command. That gives you the number of bytes, which when divided by 10242 = 1048576 gives you the MFT size in MiB.
It's even a tiny bit more precise than the value reported by Sysinternals'
fsutil gives me
0x000000006c280000 = 1730.5 MiB, while the
ntfsinfo tool reports 1730.
If you're on Windows 10, you can get the same info for any file with a different mode of the
fsutil volume filelayout c:\$mft
Check the Size row under the