Find size of Git repository

Note that, since git 1.8.3 (April, 22d 2013):

"git count-objects" learned "--human-readable" aka "-H" option to show various large numbers in Ki/Mi/GiB scaled as necessary.

That could be combined with the -v option mentioned by Jack Morrison in his answer.

git gc
git count-objects -vH

(git gc is important, as mentioned by A-B-B's answer)

Plus (still git 1.8.3), the output is more complete:

"git count-objects -v" learned to report leftover temporary packfiles and other garbage in the object store.

UPDATE git 1.8.3 introduced a more efficient way to get a rough size: git count-objects -vH (see answer by @VonC)

For different ideas of "complete size" you could use:

git bundle create tmp.bundle --all
du -sh tmp.bundle

Close (but not exact:)

git gc
du -sh .git/

With the latter, you would also be counting:

• hooks
• config (remotes, push branches, settings (whitespace, merge, aliases, user details etc.)
• stashes (see Can I fetch a stash from a remote repo into a local branch? also)
• rerere cache (which can get considerable)
• reflogs
• backups (from filter-branch, e.g.) and various other things (intermediate state from rebase, bisect etc.)

The git command

git count-objects -v

will give you a good estimate of the git repository's size. Without the -v flag, it only tells you the size of your unpacked files. This command may not be in your $PATH, you may have to track it down (on Ubuntu I found it in /usr/lib/git-core/, for instance).

From the Git man-page:

-v, --verbose

In addition to the number of loose objects and disk space consumed, it reports the number of in-pack objects, number of packs, disk space consumed by those packs, and number of objects that can be removed by running git prune-packed.

Your output will look similar to the following:

count: 1910
size: 19764
in-pack: 41814
packs: 3
size-pack: 1066963
prune-packable: 1
garbage: 0

The line you're looking for is size-pack. That is the size of all the packed commit objects, or the smallest possible size for the new cloned repository.

You could use git-sizer. In the --verbose setting, the example output is (below). Look for the Total size of files line.

$ git-sizer --verbose
Processing blobs: 1652370
Processing trees: 3396199
Processing commits: 722647
Matching commits to trees: 722647
Processing annotated tags: 534
Processing references: 539
| Name                         | Value     | Level of concern               |
| ---------------------------- | --------- | ------------------------------ |
| Overall repository size      |           |                                |
| * Commits                    |           |                                |
|   * Count                    |   723 k   | *                              |
|   * Total size               |   525 MiB | **                             |
| * Trees                      |           |                                |
|   * Count                    |  3.40 M   | **                             |
|   * Total size               |  9.00 GiB | ****                           |
|   * Total tree entries       |   264 M   | *****                          |
| * Blobs                      |           |                                |
|   * Count                    |  1.65 M   | *                              |
|   * Total size               |  55.8 GiB | *****                          |
| * Annotated tags             |           |                                |
|   * Count                    |   534     |                                |
| * References                 |           |                                |
|   * Count                    |   539     |                                |
|                              |           |                                |
| Biggest objects              |           |                                |
| * Commits                    |           |                                |
|   * Maximum size         [1] |  72.7 KiB | *                              |
|   * Maximum parents      [2] |    66     | ******                         |
| * Trees                      |           |                                |
|   * Maximum entries      [3] |  1.68 k   | *                              |
| * Blobs                      |           |                                |
|   * Maximum size         [4] |  13.5 MiB | *                              |
|                              |           |                                |
| History structure            |           |                                |
| * Maximum history depth      |   136 k   |                                |
| * Maximum tag depth      [5] |     1     |                                |
|                              |           |                                |
| Biggest checkouts            |           |                                |
| * Number of directories  [6] |  4.38 k   | **                             |
| * Maximum path depth     [7] |    13     | *                              |
| * Maximum path length    [8] |   134 B   | *                              |
| * Number of files        [9] |  62.3 k   | *                              |
| * Total size of files    [9] |   747 MiB |                                |
| * Number of symlinks    [10] |    40     |                                |
| * Number of submodules       |     0     |                                |

[1]  91cc53b0c78596a73fa708cceb7313e7168bb146
[2]  2cde51fbd0f310c8a2c5f977e665c0ac3945b46d
[3]  4f86eed5893207aca2c2da86b35b38f2e1ec1fc8 (refs/heads/master:arch/arm/boot/dts)
[4]  a02b6794337286bc12c907c33d5d75537c240bd0 (refs/heads/master:drivers/gpu/drm/amd/include/asic_reg/vega10/NBIO/nbio_6_1_sh_mask.h)
[5]  5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c (refs/tags/v2.6.11)
[6]  1459754b9d9acc2ffac8525bed6691e15913c6e2 (589b754df3f37ca0a1f96fccde7f91c59266f38a^{tree})
[7]  78a269635e76ed927e17d7883f2d90313570fdbc (dae09011115133666e47c35673c0564b0a702db7^{tree})
[8]  ce5f2e31d3bdc1186041fdfd27a5ac96e728f2c5 (refs/heads/master^{tree})
[9]  532bdadc08402b7a72a4b45a2e02e5c710b7d626 (e9ef1fe312b533592e39cddc1327463c30b0ed8d^{tree})
[10] f29a5ea76884ac37e1197bef1941f62fda3f7b99 (f5308d1b83eba20e69df5e0926ba7257c8dd9074^{tree})