How can I estimate the size of my gzipped script?

Question

How can I estimate the size of my JavaScript file after it is gzipped? Are there online tools for this? Or is it similar to using winzip for example?

score 133 · Answer 1 · answered Feb 27 '12 at 16:34

133

If you're on unix - gzip -c filename.min.js | wc -c will give you a byte count of the gzipped file

answered Feb 27 '12 at 16:34

gnarf

105,192
25
127
161

5

@Christophe : gzip is available on Windows through Cygwin or UnxUtils. – Mauricio Scheffer Feb 27 '12 at 16:44
4

Thanks, this is also useful to know raw unzipped byte size by doing `gunzip -c myfile | wc -c` or `zcat myfile | wc -c` – Adrien Schuler Oct 28 '13 at 13:58
2

To get the un-gzipped size of an un-gzipped file: `cat filename.js | wc -c`. – Jess Telford Mar 12 '19 at 01:39

score 56 · Accepted Answer · answered Feb 27 '12 at 16:43

http://closure-compiler.appspot.com/home lets you paste in code, and it will give you compression ratios for a particular file before and after GZIP.

Original Size:    90 bytes (100 bytes gzipped)
Compiled Size:    55 bytes (68 bytes gzipped)
Saved 38.89% off the original size (32.00% off the gzipped size)

You can use the pretty-print and white-space only options to estimate the compression of non-minified content.

If you need an estimate:

Start with 100 JS files that have gone through the same minification pipeline.
For each file, compute the ratio in sizes between gzip -c "$f" | wc -c and wc -c "$f"
The average of those ratios is an approximation of the compression you should expect for a similar JS file.

Cygwin contains command line implementations of gzip and wc for Windows.

thx! I'll try Cygwin, but for now the closure compiler gave me the answer I needed. — Christophe, Feb 28 '12 at 06:30

score 16 · Answer 3 · answered Jun 10 '15 at 08:11

Directly from the terminal,

gzip -9 -c path/to/file.js | wc -c | numfmt --to=iec-i --suffix=B --padding=10

If you need the original size for comprison,

cat path/to/file.js | wc -c | numfmt --to=iec-i --suffix=B --padding=10

To get it programatically there are utilities like gzip-size. It's a node package but you can install it globally as a general tool.

Scott Rippey · Answer 4 · 2015-03-23T18:32:59.103

9

7-zip supports compressing to the GZIP format.

I often use this to approximate and compare file sizes.

When creating an archive, look for Archive Format, and gzip is the 3rd option.

Update:

In the comments, we discussed that there might be a difference between 7-zip's GZIP compression, versus an actual server's GZIP compression. So, I compared using just the homepage of http://www.google.com/.
Google's GZIP'd payload was 36,678 bytes. 7-zip, with "gzip Normal" setting, was 35,559 (3% smaller). With "gzip Fastest" setting, it was 37,673 (3% larger).

So, long story short: 7-zip had results that were about 97% accurate.

edited Mar 23 '15 at 18:32

answered Oct 18 '13 at 22:03

Scott Rippey

15,614
5
70
85

1

Sorry, [7-zip](http://www.7-zip.org/) can make **smaller* archives than most CLI GZIP packers. Great if you want the smallest, bad if you want a precise byte count for what most web servers will make on the fly (which I assume is the intended scenario? – tomByrer Jan 04 '14 at 15:13
@tomByrer Thanks for the info ... can you back it up with any documentation? 7-zip has a lot of options for gzip, maybe some of them could be configured to match CLI GZIP. – Scott Rippey Jan 06 '14 at 05:27
[This](http://www.tomshardware.com/reviews/winrar-winzip-7-zip-magicrar,3436-9.html) is the best test I can Goggle right now. I made a small gzip comparison with gzip vs 7zip vs zopfli a week ago; I'll have to add more tests & formatting which will add time. In the mean while, why don't you provide such tests to prove your point please? :) – tomByrer Jan 06 '14 at 18:48
@tomByrer Oh, I think you're confused. Maybe I need to re-word my answer. 7-Zip (the **application**) supports multiple compression formats, including GZIP. I'm not talking about 7z (the **compression format**), which is undoubtedly better than gzip. – Scott Rippey Jan 07 '14 at 18:02
I understand; I've used 7zip to produce gzip files. .7z won't open in browsers :) However, I always use the Ultra level, 258 (max) word size. So you can be correct that 7zip to size what servers' gzip will produce. I am truly interested in knowing that settings. Do all servers use the same gzip config? – tomByrer Jan 08 '14 at 16:52
https://zopfli.googlecode.com/files/Data_compression_using_Zopfli.pdf by Jyrki Alakuijala, Ph.D. and Lode Vandevenne, M.Sc. (Google Inc.) tested `gzip 9` vs `7zip mm=Deflate mx=9`. 7zip was constantly smaller in varying degrees. If the range of variance was smaller, I would recommend it (I'm a 7-zip fanboi myself). – tomByrer Nov 21 '14 at 17:15
1

Alright, I updated my answer with a quick test. I tested google.com, and found that 7-zip was 3% smaller. For most people, this ought to be acceptable. – Scott Rippey Feb 13 '15 at 23:48

score 7 · Answer 5 · edited Oct 17 '16 at 08:45

7

http://refresh-sf.com/ will give you minification and gzip ratios & sizes.

edited Oct 17 '16 at 08:45

Sachin Joseph

18,928
4
42
62

answered Jul 16 '14 at 22:28

JosephSlote

316
2
10

score 4 · Answer 6 · answered Aug 19 '19 at 12:45

4

With node core, you can use the length of the zlib.gzip buffer to determine the gzip size:

const fs = require('fs');
const util = require('util');
const zlib = require('zlib');
const readFile = util.promisify(fs.readFile);
const gzip = util.promisify(zlib.gzip);

const getGzipSize = filePath => readFile(filePath)
  .then(gzip)
  .then(x => x.length);

answered Aug 19 '19 at 12:45

charlespwd

528
4
10

Thanks, this is what I was seeking, to use it with the github script action. Also there are the sync api available: `const gzipSizeInKb = Math.round((zlib.gzipSync(content).length / 1024) * 100) / 100;` – Dr. Lemon Tea Apr 20 '23 at 21:22

score 2 · Answer 7 · answered Dec 20 '18 at 14:44

2

If you want to compare uncompressed, gzipped, and brotli'ed file sizes for the whole folder: (assuming you want to filter *.js):

for file in *.js; do printf "$file\t$(cat $file | wc -c)\t$(gzip -kc7 $file | wc -c)\t$(brotli --in $file --out temp.br --force --quality 11 && cat temp.br | wc -c)\n"; done | tee filesizes.log

Sample output (tab-separated so you can copy to a spreadsheet):

foo.js 39035   10150   8982
bar.js 217000  68978   56337

answered Dec 20 '18 at 14:44

jakub.g

38,512
12
92
130

1

Removed usage of unnecessary temp file, and saving of output to `filesizes.log`. Added commas to output to improve readability. Bumped gzip compression level to 9 to match the already maxed-out brotli compression level of 11. ```for file in *.js; do printf "$file\t$(cat $file | wc -c | xargs printf "%'d\n")\t$(gzip -9c $file | wc -c | xargs printf "%'d\n")\t$(brotli -cZ $file | wc -c | xargs printf "%'d\n")\n"; done | tee``` – mrienstra Jul 09 '19 at 01:29

score 0 · Answer 8 · answered Mar 28 '15 at 13:38

0

You can install gzip itself on Windows via Gow (Gnu On Windows).

answered Mar 28 '15 at 13:38

tomByrer

1,105
12
21

score 0 · Answer 9 · answered Jun 14 '23 at 07:24

0

If you're working in VSCode, then I can recommend this extension: https://marketplace.visualstudio.com/items?itemName=mkxml.vscode-filesize

answered Jun 14 '23 at 07:24

Maximilian Friedmann

290
3
15

How can I estimate the size of my gzipped script?

9 Answers9

7-zip supports compressing to the GZIP format.

Update: