File Size Checker

Drop any group of files here to read their exact byte counts, see the running total, and watch the same number expressed in every unit from bytes to petabytes.

What is the File Size Checker?

The File Size Checker reads the size, name and MIME type your browser reports for each file you add, then adds the sizes together. Nothing is opened or read beyond that metadata, and no bytes are sent anywhere. The totals panel divides by 1024 at each step, so the KB, MB and GB figures shown are binary units of the kind Windows Explorer uses.

Key Features

• Add files by clicking the drop zone or dragging them in
• Running total and file count update as you add or remove items
• Same total shown in bytes, KB, MB, GB, TB and PB
• Color-coded icons flag images, video, audio, PDFs, archives and text files
• Each row shows the browser-reported MIME type beside the size

Common Use Cases

• Checking whether a batch of photos will clear a 25 MB mail limit
• Weighing a folder of assets before uploading it to a client portal
• Confirming an export finished at the size the exporting app claimed
• Settling why a file reads 1.4 MB in one place and 1.5 in another

How to Use the File Size Checker

1. Drag your files onto the dashed upload zone, or click it to browse.
2. Watch each file appear in the File List with its type and size badge.
3. Read the running total and file count in the bar below the drop zone.
4. Open the Total Size in All Units panel to see that figure in six units.
5. Use the red X on any row to drop a file, or Clear All to start over.

Tips for Best Results

• Sizes here are logical byte counts; on disk a tiny file still occupies a whole allocation block.
• Add files in the order you plan to attach them so the running total mirrors your message.
• Mail limits usually apply to the whole message, so leave headroom below the stated cap.
• A blank type column just means your browser could not guess a MIME type from the extension.

Why Use WiserWork's File Size Checker?

Most file managers round aggressively and show only one unit, which is exactly when you want a second opinion. This page gives you the raw byte count and every unit at once, and because it only ever touches metadata your files never leave the machine.

Who Uses the File Size Checker?

People assembling email attachments, anyone preparing an upload against a stated size cap, and developers checking that a build artifact or export came out the size they expected. It also settles the arguments that start when a colleague quotes a size that does not match what you see.

Frequently Asked Questions

Does this tool upload my files?

No. It reads only the name, size and MIME type the browser exposes for each file. The contents are never opened, let alone transmitted.

Are the KB and MB figures based on 1000 or 1024 bytes?

1024. Every step in the unit panel divides by 1024, so what is labeled KB is technically a kibibyte, the same convention Windows uses in File Explorer.

Why does a 1 TB drive show up as roughly 931 GB?

Drive makers count a terabyte as 1,000,000,000,000 bytes, while Windows divides by 1024 three times. No storage went missing; only the arithmetic differs.

Why does macOS report a bigger number than this tool?

Since Mac OS X 10.6, Finder has used decimal units and divides by 1000. The underlying byte count is identical; the label is doing different math.

What is the largest file I can check?

There is no cap, because the file is never read. Adding a hundred-gigabyte disk image resolves as fast as adding a text document.

Can I check a whole folder at once?

Not as a folder. Select everything inside it in the picker, or drag the contents onto the zone, and the running total does the rest.

Why did my 20 MB attachment get rejected by a 25 MB limit?

Attachments are re-encoded as text for transport, which inflates them by roughly a third, and headers and the message body count toward the ceiling too. Aim comfortably under it.

Does size on disk match what I see here?

Often not. Filesystems allocate space in blocks, commonly 4 KB, so a 300-byte file consumes 4 KB of disk while this tool honestly reports 300 bytes.

Why do the unit cards show four decimal places?

So a small file stays readable in a large unit. Any value under 0.01 in a given unit switches to scientific notation rather than rounding away to zero.

Does the file list survive a page reload?

No. The list lives in a JavaScript array in memory, so refreshing or closing the tab empties it and nothing is stored on your device.

File sizes only get confusing when two programs disagree about what a megabyte is. Keeping the byte count and all six units side by side makes that disagreement obvious instead of mysterious.