Change Number’s Mantissa

Change Number’s Mantissa lets you modify the decimal portion of any number quickly and cleanly. You can lock in a fixed mantissa, randomize it, or match the original precision all with a live preview and export options. Whether you’re transforming values or testing formatting logic, this tool makes it easy to shift just the part after the decimal.

Paste your input above or import a file below.
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Supported file types: .txt, .csv, .log, .json, .xml, .md, .ini, .yaml, .yml, .html, .htm, .css
Total characters: 0
Options
Preserve Scientific Notation
Trim trailing zeros
Include original in output
Maximize output

How to Use:

Start by entering your numbers into the input box on the left. Each number should go on its own line. You can paste the values manually or load them from a text file using Choose File. Supported formats include .txt, .csv, .json, and other safe plain-text types.

Next, use the Options box to configure how the tool changes the mantissa:

  • Set a fixed Mantissa value to apply to every number (e.g. 0.5)
  • Turn on Preserve negative signs if you want to keep the minus on negative numbers
  • Use Match original decimal length to maintain the same number of decimal places
  • Toggle Randomize mantissa to use a new random decimal each time instead of a fixed one

Everything updates instantly as you type or toggle settings. The output flashes blue on change, and you can copy the result, export it to a file, or clear everything using the buttons underneath.

What Change Number’s Mantissa can do:

This tool separates each number into its integer and decimal parts, then reconstructs it using the mantissa settings you define. You can force a consistent decimal, randomize each one, or match the original’s length to keep the output looking clean.

It works entirely in your browser no uploads or delays. A counter shows the total character count of the output, and changes apply line-by-line with full control over formatting and sign preservation.

Example:

Input:

3.14
-2.71
8.00

Options:Mantissa: 0.5, Preserve negatives: ON, Match decimals: ON

Output:

3.50
-2.50
8.50

Common Use Cases:

Change Number’s Mantissa is useful when you want to standardize or manipulate the decimal portion of numbers without affecting the integer part. It’s great for rounding simulations, formatting prep, data mocking, or simply experimenting with numerical patterns. The live preview and easy toggles make it fast to try variations and get immediate results.

Useful Tools & Suggestions:

Pair this with Change Number’s Exponent if you’re adjusting scientific notation and want full control over format. And if you’re curious about what the digits actually mean in terms of randomness, give Find Entropy of a Number a try too.

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