01
ZIP File Creator
Packs any set of files into a single .zip archive inside your browser, with a choice of…
ZIP Compression Comparer
Zips the same files at every compression level and shows the real size and time for each, so you can see what Best actually buys over Fastest.
Developer
Nothing uploaded
No sign-up
Free, unlimited
Drop the files to testeach level is built for real — nothing is estimated
Add a file to begin.
In short
ZIP Compression Comparer is a free online tool on inputtesthub.com that zips the same files at every compression level and shows the real size and time for each, so you can see what Best actually buys over Fastest. It needs no account, no download and no payment, and there is no daily usage limit. Everything is processed inside your own browser, so the data you paste is never uploaded to a server.
How to use the ZIP Compression Comparer
- Drop in a representative sample of your files.
- Run the comparison.
- Read the gap between Fastest and Best, not the absolute sizes.
About the ZIP Compression Comparer
The ZIP Compression Comparer zips the same files at every compression level and shows the real size and time for each, so you can see what Best actually buys over Fastest. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Deciding whether Best compression is worth the wait for a large archive.
- Showing someone why zipping a video folder saves nothing.
- Picking a level for an automated backup that runs every night.
Details
| Method | Every level is genuinely built and measured, not estimated |
|---|---|
| Levels | Store (0), Fastest (1), Default (6), Best (9) |
| Typical gain, level 1 to 9 | A few percent on text; nothing on media |
| Timing | Measured in this browser, so it reflects your machine |
Running four full compressions of the same input is the point — every "compression level comparison" table online is generic, and the only figure that matters is what your files do. A sample of a few representative files answers the question better than a whole folder.
Where this tool stops
Times are wall-clock in a browser tab and will vary between runs. Very large inputs are compressed four times over, so keep the sample modest.
Frequently asked questions
Which level should I use?
Default, almost always. The interesting comparison is Fastest against Best: on text and source code that gap is usually two to five percent for several times the CPU time, and on already-compressed files it is zero. Best earns its time on large text archives and very little else.
Why is Store sometimes the same size as Best?
Because the files cannot be compressed. When every byte of input is already dense — JPEG, MP4, another zip — deflate finds no repetition to exploit and simply copies the data through, plus a little header per entry.
Do the timings mean anything?
Relatively, yes; absolutely, no. They are measured in your browser on your machine, competing with everything else the tab is doing. Use them to compare the levels against each other, not to predict what a server will take.
Is the ZIP Compression Comparer free?
It is free, with no account, no trial and no daily cap. Every developer tool on inputtesthub.com works the same way: open the page and use it.
Is my data uploaded anywhere?
No. The ZIP Compression Comparer runs entirely in your browser using JavaScript. Because the work happens locally, the tool also keeps working if your connection drops, and closing the tab is all it takes to discard everything.
What problem does the ZIP Compression Comparer solve?
The most common reasons people reach for it: deciding whether Best compression is worth the wait for a large archive. Showing someone why zipping a video folder saves nothing. Picking a level for an automated backup that runs every night. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is there anything the ZIP Compression Comparer cannot do?
Times are wall-clock in a browser tab and will vary between runs. Very large inputs are compressed four times over, so keep the sample modest. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What figures does the ZIP Compression Comparer work from?
Method is Every level is genuinely built and measured, not estimated. Levels is Store (0), Fastest (1), Default (6), Best (9). Typical gain, level 1 to 9 is A few percent on text; nothing on media. These are printed on the page itself, so you do not have to take them on trust.
Is there a file size limit?
There is no limit set by us, because your file is never uploaded — the only ceiling is the memory your own browser will give the tab. Very large files simply take longer to process, and a phone will give up sooner than a desktop.
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