Fun data-size comparison

How Many Libraries of Congress Is My Data?

Enter any data size and see it compared to the (famously fuzzy) estimate for the U.S. Library of Congress's printed collection — plus floppy disks, CDs and DVDs for good measure.

 
0Libraries of Congress
0%of one LOC (~10TB)
0total bytes
This uses the commonly cited, admittedly fuzzy estimate that the Library of Congress's printed and text collection is roughly 10 terabytes — a widely-referenced approximation, not an exact or official figure.
Also equivalent to…
01.44MB floppy disks
0700MB CDs
04.7GB DVDs

Why compare data to Libraries of Congress

Byte counts stop meaning much once you get past a few gigabytes. Comparing your data to something tangible — even a fuzzy estimate of a famous library — makes the scale click instantly.

Human-scale intuition

"Half a Library of Congress" lands differently than "5.4 terabytes," even though they describe the same thing.

Honest about the fuzziness

The ~10TB figure is a commonly repeated estimate, not a precise measurement, and this tool says so clearly.

Nostalgic bonus comparisons

See the same number of floppy disks, CDs and DVDs it would take, for a fun trip through storage history.

How to use the comparison tool

  1. Enter a sizeType any data size, from a few kilobytes to multiple petabytes.
  2. Pick a unitChoose KB, MB, GB, TB or PB from the dropdown.
  3. Read the comparisonSee the Library of Congress count, the visual grid and the percentage.
  4. Check the extrasScroll down for floppy disk, CD and DVD equivalents, updated live.

About the Library of Congress estimate

The Library of Congress is one of the largest libraries in the world, holding tens of millions of books, manuscripts, maps, photographs and recordings. Because that collection is so varied — and because the Library itself doesn't publish one single "total data size" figure — people commonly cite a rough estimate of around 10 terabytes for just the printed and text-based portion of the collection. That number gets repeated so often in tech and trivia contexts that it has become a kind of informal yardstick for "a huge amount of text," even though it's an approximation rather than an audited measurement. This tool leans into that popular usage for fun, while being upfront that it's a rough, widely-cited estimate rather than an exact figure — the real collection includes vastly more data once you count digitized images, audio and video.

~10TB estimate

The commonly cited approximation for the Library's printed and text collection, used as the baseline here.

KB to PB support

Works for anything from a text file to a datacenter's worth of storage.

100% client-side

All math happens instantly in your browser — nothing is uploaded or saved.

Data size comparison FAQ

How big is the Library of Congress's collection, really?

There's no single official figure, since the collection keeps growing and includes far more than text. A commonly cited rough estimate for just the printed and text portion is about 10 terabytes, and that's the widely-referenced approximation this tool uses — not an exact measurement.

Why does the 10 terabyte estimate vary between sources?

It depends on what's being counted — books versus manuscripts, digitized versus physical originals, and text versus the Library's much larger photo, audio and video holdings. Any single number here is necessarily a rough approximation, which this tool states plainly.

Is a floppy disk really 1.44MB?

Yes. A standard 3.5-inch high-density floppy disk holds about 1.44MB, which this tool uses as a nostalgic size reference alongside CDs and DVDs.

What happens if my data size is really large or really small?

The tool automatically switches between decimal formatting and scientific notation so results stay readable, whether you're comparing a few kilobytes or several exabytes.

Does this tool upload or store my data?

No. You're only entering a number and a unit — no files are uploaded, and nothing you type is saved or sent anywhere.

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