Choose a version:
38% The original file has 238159 bytes (232.6k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 91669 bytes (89.5k, 38%).

After GZIP compression these minified files vary in size:
Microsoft
  40863 bytes (39.9k)
CDN
Boot
  37133 bytes (36.3k)
CDN
cdnjs
  32356 bytes (31.6k)
CDN
Baidu
  32355 bytes (31.6k)
CDN
gzip -6 (default)
  32131 bytes (31.4k)
local copy
cdnhttps
  32111 bytes (31.4k)
CDN
Google
  32103 bytes (31.4k)
CDN
gzip -9
  32071 bytes (31.3k)
local copy
kzip -s0 -rn -b0
  30969 bytes (30.2k)
local copy
7zip -mx=9 -tgzip
  30948 bytes (30.2k)
local copy
Yandex
  30911 bytes (30.2k)
CDN
libdeflate -12
  30905 bytes (30.2k)
local copy
pigz -11 -n
  30890 bytes (30.2k)
local copy
Zopfli
  30858 bytes (30.1k)
local copy
Zopfli (defluff)
  30857 bytes (30.1k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-1.6.4.min.js

You will automatically get the smallest jQuery 1.6.4 file, ETag caching is available and
if your browser doesn't support GZIP decompression then the uncompressed version will be sent.

Currently best Zopfli settings

Save 53 bytes by using my jQuery 1.6.4 Zopfli version instead of the best available CDN (0.17% smaller than Yandex, 30858 vs. 30911 bytes):
You can use my super-compressed files for whatever purpose you like as long as you respect the library's original license agreement.
There are no restrictions from my side - but please avoid hot-linking if you run a high-traffic website.

These command-line settings yielded the best compression ratio so far (Linux version of zopfli-krzymod):
zopfli --i100000 --mb8 --mls8192 --bsr19 --lazy --ohh

(found January 8, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 8192  --mls8192
block splitting recursion 19  --bsr19
lazy matching in LZ77 yes  --lazy
optimized Huffman headers yes  --ohh
initial random W for iterations 1  --rw1
initial random Z for iterations 2  --rz2

Even Smaller Files Thanks To Defluff

Zopfli's output can be further optimized by the defluff tool.
In this particular case, defluff saves 1 more byte (30857 bytes).

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed http://code.jquery.com/jquery-1.6.4.min.js --location | md5sum
9118381924c51c89d9414a311ec9c97f  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.6.4.min.zopfli.js.gz | md5sum
9118381924c51c89d9414a311ec9c97f  -

SHA1:
curl --silent --compressed http://code.jquery.com/jquery-1.6.4.min.js --location | sha1sum
71cce71820cc47b3bd1098618d248325fcf24ddb  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.6.4.min.zopfli.js.gz | sha1sum
71cce71820cc47b3bd1098618d248325fcf24ddb  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Microsoft 40863 bytes 9118381924c51c89d9414a311ec9c97f (invalid)
Boot 37133 bytes 9118381924c51c89d9414a311ec9c97f March 18, 2015 @ 09:42
cdnjs 32356 bytes 9118381924c51c89d9414a311ec9c97f (invalid)
cdnhttps 32111 bytes 9118381924c51c89d9414a311ec9c97f December 24, 2015 @ 07:33
Yandex 30911 bytes 9118381924c51c89d9414a311ec9c97f June 15, 2015 @ 21:17

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 32355 bytes ea75b2a8f1b4241a872b1cbddbaed154 < (function(a,b){function cu(a){return f.isWindow(a)?a:a.nod [...]
> (function(a,b){function cu(a){return f.isWindow(a)?a:a.nod [...]
January 7, 2015 @ 10:16
Google 32103 bytes 219073097031d9c1a95a1291d66f3a10 < (function(a,b){function cu(a){return f.isWindow(a)?a:a.nod [...]
> (function(a,b){function cu(a){return f.isWindow(a)?a:a.nod [...]
(invalid)

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available jQuery versions at minime.stephan-brumme.com:

3.2.1, 3.2.0,
3.1.1, 3.1.0,
3.0.0,
2.2.4, 2.2.3, 2.2.2, 2.2.1, 2.2.0,
2.1.4, 2.1.3, 2.1.2, 2.1.1, 2.1.0,
2.0.3, 2.0.2, 2.0.1, 2.0.0,
1.12.4, 1.12.3, 1.12.2, 1.12.1, 1.12.0,
1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.2, 1.10.1, 1.10.0,
1.9.1, 1.9.0,
1.8.3, 1.8.2, 1.8.1, 1.8.0,
1.7.2, 1.7.1, 1.7.0,
1.6.4, 1.6.3, 1.6.2, 1.6.1, 1.6,
1.5.2, 1.5.1, 1.5,
1.4.4, 1.4.3, 1.4.2, 1.4.1, 1.4,
1.3.2, 1.3.1, 1.3,
1.2.6, 1.2.5, 1.2.4, 1.2.3, 1.2.2, 1.2.1, 1.2,
1.1.4, 1.1.3, 1.1.2, 1.1.1, 1.1,
1.0.4, 1.0.3, 1.0.2, 1.0.1, 1.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, Knockout, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
30858 bytes -2 bytes zopfli --i100000 --mls8192 --bsr19 --lazy --ohh January 8, 2016 @ 10:37
30860 bytes -2 bytes zopfli --i100000 --mls8192 --bsr9 --lazy --ohh September 2, 2015 @ 00:31
30862 bytes -3 bytes zopfli --i10000 --mls8192 --bsr9 --lazy --ohh September 1, 2015 @ 21:12
30865 bytes -1 byte zopfli --i1000 --mls4096 --bsr2 --lazy --ohh September 1, 2015 @ 20:37
30866 bytes -12 bytes zopfli --i1000 --mls8192 --bsr9 --lazy --ohh September 1, 2015 @ 20:36
30878 bytes zopfli --i100 --mls4096 --bsr12 --lazy --ohh September 1, 2015 @ 20:15

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on June 16, 2016 @ 14:39.

Heatmaps

This Zopfli heatmap visualizes how compression changes when modifying the --bsr and --mls parameter.
Cell's contents is the best filesize achieved (in bytes, hover with mouse over cells to see number of iterations).

Good parameters are green, bad are red. The best and worst are bold as well.
The brightness of the blue background color indicates how many iterations were processed:
10,000 or 100,000.
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
30879 30878 30877 30878 30878 30886 30886 30879 30881 30883 30880 30860 30866 30869 30877
30871 30872 30872 30873 30872 30874 30875 30876 30876 30876 30876 30866 30870 30876 30880
30879 30871 30871 30870 30873 30871 30873 30872 30874 30869 30873 30872 30869 30872 30869
30877 30871 30869 30871 30871 30871 30879 30873 30872 30873 30870 30871 30862 30866 30875
30872 30874 30875 30870 30870 30871 30878 30873 30872 30871 30873 30870 30863 30869 30869
30871 30875 30872 30871 30869 30871 30875 30876 30873 30870 30870 30870 30860 30866 30869
30872 30871 30875 30874 30876 30871 30877 30873 30873 30870 30873 30873 30863 30866 30875
30877 30870 30870 30875 30877 30869 30880 30873 30872 30870 30870 30872 30860 30867 30875
30877 30875 30874 30874 30870 30871 30881 30873 30872 30871 30871 30864 30865 30867 30876
30877 30870 30871 30870 30876 30871 30874 30871 30870 30870 30870 30871 30862 30866 30877
30872 30872 30872 30871 30873 30871 30875 30873 30872 30870 30870 30870 30862 30869 30875
30878 30871 30874 30874 30870 30869 30879 30873 30872 30872 30869 30870 30864 30868 30870
30877 30874 30875 30871 30870 30871 30877 30873 30870 30870 30870 30871 30862 30869 30869
30877 30870 30871 30875 30876 30870 30878 30870 30873 30870 30873 30871 30859 30866 30870
30877 30871 30877 30869 30876 30871 30877 30873 30873 30870 30870 30870 30860 30869 30876
30870 30875 30870 30873 30873 30871 30878 30873 30872 30870 30873 30871 30858 30874 30876
30877 30874 30871 30871 30875 30869 30877 30872 30871 30877 30872 30872 30862 30866 30875
30877 30869 30871 30874 30876 30870 30877 30876 30872 30871 30871 30870 30862 30866 30872
30871 30879 30875 30870 30875 30869 30878 30873 30871 30870 30870 30871 30860 30870 30873
30877 30874 30877 30874 30869 30875 30877 30871 30873 30870 30871 30870 30868 30867 30875
30878 30875 30874 30870 30870 30869 30875 30873 30873 30874 30870 30871 30859 30866 30875
30871 30876 30874 30870 30870 30870 30878 30873 30871 30870 30870 30870 30858 30866 30872
30871 30871 30870 30875 30879 30871 30879 30873 30872 30870 30870 30871 30859 30869 30876

Due to the Monte Carlo design of my search algorithm, not all parameters have reached the same number of iterations yet:
Iterations Min. Bytes Reduction Coverage
100 30877 bytes 100%
1,000 30863 bytes -14 bytes 100%
10,000 30860 bytes -3 bytes 100%
100,000 30858 bytes -2 bytes 2.90%
1,000,000
10,000,000

KZIP has far less options available for tuning/optimization. I only played around with the number of blocks (parameter -n):
Blocks Min. Bytes Compared To Best Zopfli Compared To Best KZIP
30969 bytes +111 bytes (+0.36%)
30970 bytes +112 bytes (+0.36%) +1 byte
31006 bytes +148 bytes (+0.48%) +37 bytes
31018 bytes +160 bytes (+0.52%) +49 bytes
31053 bytes +195 bytes (+0.63%) +84 bytes
31074 bytes +216 bytes (+0.70%) +105 bytes
31086 bytes +228 bytes (+0.74%) +117 bytes
31124 bytes +266 bytes (+0.86%) +155 bytes
31147 bytes +289 bytes (+0.94%) +178 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 24744 bytes -6114 bytes (-19.81%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 25464 bytes -5394 bytes (-17.48%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 27065 bytes -3793 bytes (-12.29%)
Brotli (Wikipedia) brotli brotli -q 11 28431 bytes -2427 bytes (-7.87%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 28538 bytes -2320 bytes (-7.52%)
LZMA2 (Wikipedia) xz xz -9 29568 bytes -1290 bytes (-4.18%)
ZSTD (Wikipedia) zstd zstd -19 30190 bytes -668 bytes (-2.16%)

Detailled Analysis

I wrote a DEFLATE decoder in Javascript. Click the button below to start a client-side analysis of the smallest gzipped files (may take a second):


Notes: pigz is a fast open source multi-threaded implementation of gzip written by one of the original authors of gzip.
However, when using compression level 11, pigz actually switches to the slower Zopfli algorithm and isn't multi-threaded anymore.
KrzyMOD's extensions to Zopfli offer the highest level of configuration and is therefore used for my brute-force search.
Ken Silverman wrote the closed-source KZIP compression program and Jonathon Fowler ported it to Linux.
Defluff was created by Joachim Henke; DeflOpt is a tool by Ben Jos Walbeehm.

website made by Stephan Brumme in 2015 and still improving in 2018.
all timestamps are displayed in central european time. see my changelog.
no flash, not even images or external css files - and everything squeezed into a single html file.
which was handsomely compressed before releasing it into the wild internet - obviously.

please visit my homepage and my blog, too.
email: minime (at) stephan-brumme.com