Choose a version:
39% The original file has 232651 bytes (227.2k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 90518 bytes (88.4k, 39%).

After GZIP compression these minified files vary in size:
Baidu
  31897 bytes (31.1k)
CDN, direct link
gzip -6 (default)
  31670 bytes (30.9k)
local copy
Google
  31652 bytes (30.9k)
CDN, direct link
gzip -9
  31616 bytes (30.9k)
local copy
kzip -s0 -rn -b1
  30530 bytes (29.8k)
local copy
7zip -mx=9 -tgzip
  30507 bytes (29.8k)
local copy
libdeflate -12
  30506 bytes (29.8k)
local copy
Yandex
  30458 bytes (29.7k)
CDN, direct link
pigz -11 -n
  30442 bytes (29.7k)
local copy
Zopfli
  30420 bytes (29.7k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-1.6.min.js

You will automatically get the smallest jQuery 1.6 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 38 bytes by using my jQuery 1.6 Zopfli version instead of the best available CDN (0.12% smaller than Yandex, 30420 vs. 30458 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 --mls2 --bsr19 --lazy --ohh

(found January 8, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2  --mls2
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

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.min.js --location | md5sum
3c379d07fafbaafecb78c98dd8630d0a  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.6.min.zopfli.js.gz | md5sum
3c379d07fafbaafecb78c98dd8630d0a  -

SHA1:
curl --silent --compressed http://code.jquery.com/jquery-1.6.min.js --location | sha1sum
cf36297804ca93709e18a7f9de289610bc97f9c5  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.6.min.zopfli.js.gz | sha1sum
cf36297804ca93709e18a7f9de289610bc97f9c5  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Google 31652 bytes 3c379d07fafbaafecb78c98dd8630d0a (invalid)
Yandex 30458 bytes 3c379d07fafbaafecb78c98dd8630d0a June 15, 2015 @ 21:17

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 31897 bytes 1c0617003ec0726ebfd589ff21ea128b only whitespaces differ January 7, 2015 @ 10:16

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
30420 bytes -1 byte zopfli --i100000 --mls2 --bsr19 --lazy --ohh January 8, 2016 @ 04:58
30421 bytes -3 bytes zopfli --i100000 --mls8192 --bsr16 --lazy --ohh September 2, 2015 @ 00:52
30424 bytes -1 byte zopfli --i10000 --mls8192 --bsr16 --lazy --ohh September 1, 2015 @ 21:19
30425 bytes -8 bytes zopfli --i1000 --mls8192 --bsr16 --lazy --ohh September 1, 2015 @ 20:38
30433 bytes zopfli --i100 --mls8192 --bsr11 --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 @ 14:41.

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
30437 30435 30439 30435 30428 30440 30426 30430 30428 30433 30423 30428 30425 30433 30438
30428 30427 30428 30426 30425 30427 30427 30428 30431 30434 30430 30428 30429 30432 30427
30427 30428 30426 30433 30427 30428 30427 30429 30429 30428 30428 30426 30426 30429 30430
30431 30432 30431 30431 30426 30431 30428 30427 30427 30426 30423 30424 30424 30432 30430
30424 30429 30426 30426 30427 30429 30427 30428 30429 30426 30428 30427 30424 30432 30428
30426 30428 30426 30428 30426 30427 30426 30426 30426 30426 30422 30426 30428 30430 30435
30425 30429 30426 30427 30426 30431 30429 30429 30429 30426 30428 30428 30427 30427 30430
30425 30429 30425 30430 30426 30429 30429 30429 30429 30426 30428 30427 30424 30432 30436
30428 30428 30425 30429 30424 30428 30428 30429 30429 30426 30426 30425 30425 30432 30435
30426 30429 30426 30426 30427 30427 30431 30428 30426 30427 30427 30425 30426 30430 30431
30427 30429 30428 30427 30428 30431 30429 30426 30428 30425 30428 30425 30428 30432 30431
30426 30429 30425 30427 30427 30427 30428 30429 30429 30426 30427 30425 30423 30432 30428
30427 30429 30428 30434 30430 30429 30428 30429 30429 30427 30427 30425 30421 30432 30432
30428 30429 30428 30429 30426 30430 30428 30427 30427 30427 30428 30425 30425 30432 30430
30428 30429 30434 30428 30429 30430 30428 30427 30429 30426 30428 30426 30424 30432 30428
30420 30429 30434 30430 30426 30428 30427 30429 30429 30428 30426 30424 30426 30430 30438
30423 30428 30429 30428 30428 30428 30425 30429 30428 30426 30427 30423 30424 30429 30435
30424 30429 30434 30428 30426 30428 30428 30429 30426 30426 30426 30424 30424 30431 30429
30423 30429 30434 30430 30427 30431 30427 30429 30429 30426 30429 30424 30420 30432 30431
30424 30429 30427 30425 30425 30430 30427 30429 30429 30426 30428 30425 30424 30430 30431
30424 30429 30434 30424 30424 30427 30428 30429 30429 30426 30428 30424 30424 30430 30432
30426 30429 30430 30428 30426 30427 30429 30429 30429 30426 30427 30424 30430 30432 30436
30427 30429 30427 30435 30428 30430 30428 30429 30429 30426 30426 30423 30424 30432 30430

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 30432 bytes 100%
1,000 30425 bytes -7 bytes 100%
10,000 30421 bytes -4 bytes 100%
100,000 30420 bytes -1 byte 1.16%
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
30533 bytes +113 bytes (+0.37%) +3 bytes
30530 bytes +110 bytes (+0.36%)
30571 bytes +151 bytes (+0.50%) +41 bytes
30560 bytes +140 bytes (+0.46%) +30 bytes
30564 bytes +144 bytes (+0.47%) +34 bytes
30595 bytes +175 bytes (+0.58%) +65 bytes
30617 bytes +197 bytes (+0.65%) +87 bytes
30637 bytes +217 bytes (+0.71%) +107 bytes
30675 bytes +255 bytes (+0.84%) +145 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 24479 bytes -5941 bytes (-19.53%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 25201 bytes -5219 bytes (-17.16%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 26635 bytes -3785 bytes (-12.44%)
Brotli (Wikipedia) brotli brotli -q 11 28032 bytes -2388 bytes (-7.85%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 28237 bytes -2183 bytes (-7.18%)
LZMA2 (Wikipedia) xz xz -9 29180 bytes -1240 bytes (-4.08%)
ZSTD (Wikipedia) zstd zstd -19 29835 bytes -585 bytes (-1.92%)

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 2017.
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