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ZMakeMyZip
job card · № 10 of 19 · peek

Estimate Compression.

Try every ZIP compression level on your files and see how small each makes the archive before you commit. All four passes run locally.

routeclient-local
upload0 B
formatsZIP

1. Drop your files

Drop files or a folder here or click to browse

Select one or more files

Up to 2 GB per file.

2. Run the estimate

We compress your files four times — once at each level — and report the resulting archive size and time taken. Nothing is uploaded; the four passes all run in this tab.

instructions · step by step

How to use this tool

Run every ZIP compression level on your files locally and compare the resulting archive sizes.

  1. Open the Estimate Compression tool

    Visit makemyzip.com/estimate-compression. The JavaScript ZIP engine loads on demand.

  2. Drop your files

    Drag files or a folder onto the dropzone. The same set is compressed four times — once at each level — so the comparison is apples to apples.

  3. Run the estimate

    Click Estimate all four levels. The tool packs the archive at Store, Fast, Normal, and Max, measuring the output size and time each takes.

  4. Read the table

    Each row shows the resulting archive size, its ratio against the source, and how long compression took. The smallest result is flagged.

  5. Pick a level and move on

    If Normal and Max are within a couple of percent, Normal is the right pick. If the ratio is near 100%, your files are already compressed — pick Store.

questions · from the clerk's desk

Frequently asked questions

Does it upload my files to run the estimate?

No. All four compression passes run in your browser tab. The original files and the compressed results stay in memory on your machine.

Why does it take so long on large inputs?

The tool compresses the same bytes four times. Max (DEFLATE level 9) is the slowest pass by a wide margin. On multi-gigabyte inputs, expect the full run to take a minute or more.

What do the levels map to?

Store is no compression (just packaging). Fast is DEFLATE level 3. Normal is DEFLATE level 6 (the usual default). Max is DEFLATE level 9 — slowest, smallest.

Is this an exact preview of Create ZIP output?

Byte-for-byte identical to what Create ZIP would produce at the same level — both tools use the same engine and settings.

3 picks
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