Perturb Numbers

Perturb Numbers lets you randomly modify numeric values with adjustable error settings, right in your browser. You can add fixed or percentage-based noise to your data, control decimal precision, and even show the original values alongside the modified ones. Everything updates live as you type.

Paste your input above or import a file below.
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Supported file types: .txt, .csv, .tsv, .log, .json, .xml, .md, .ini, .yaml, .yml, .html, .htm, .css
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Options
Use decimal precision
Include original value

How to Use:

Start by entering your numbers into the input box on the left. You can type them in directly or import a supported text file like .txt, .csv, or .json. Each number should go on its own line.

Then open the Options box to fine-tune the output. Choose whether the error applied is absolute (fixed range) or percentage-based (relative to each number). Set the Max Error using the number input field. You can toggle Use decimal precision to control whether the output is rounded or shows decimals. And if you want to compare the original and perturbed values side-by-side, turn on Include original value.

Results appear live in the right-hand box with each update flashing. Use the buttons below to copy the output, export it as a .txt file, or clear everything.

What Perturb Numbers can do:

Perturb Numbers adds a small dose of randomness to numeric lists. It’s useful when you need to test robustness, simulate real-world variability, or obscure data while keeping it realistic. The error mode lets you choose whether the perturbation is a flat amount (like ±5) or a percent of the original value (like ±5%).

You can also control whether the final values are precise decimals or just rounded, and optionally show both the original and new number together. All processing happens instantly in your browser no uploads, no delays. The dynamic counter below the output tells you how many values have been generated.

Example:

Input:

100
200
300
400
500

Output (absolute mode, Max Error 5, show original ON):

100 → 97.7321
200 → 204.1633
300 → 296.5731
400 → 403.1207
500 → 497.0189

Common Use Cases:

Whether you’re testing a calculation script, building synthetic datasets, or introducing variability for obfuscation, Perturb Numbers gives you direct control over how much each number changes. Switch between absolute and percentage errors, keep or hide the original, round the results or not it’s all adjustable in one place.

Useful Tools & Suggestions:

If you’re already adding variation, Add Errors to Numbers gives you control over how much the values shift by percentage or absolute change. You could also check out Perturb Number Digits if you want to scramble digits without changing the whole number too wildly.

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