How it works
Round numbers to specific decimal places using various methods.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
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?number=NumberNumber · Optional · Default: 123.456789
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?precision=Decimal PlacesNumber · Optional · Default: 2
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?mode=ModeChoice · Optional · Default: round
Outputs
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resultResultText · Primary output
result contains the calculator’s complete rendered result area, including its visible result cards, tables, charts, and messages.
Round numbers using various mathematical methods
Description
The Rounding Calculator is a precision tool for managing decimal numbers. It allows you to shorten numbers to a specific number of decimal places while choosing between four different mathematical behaviors. This is useful for financial reporting, scientific data processing, or simplifying complex figures for better readability.
Inputs
- Number: The decimal or integer you wish to round.
- Decimal Places: The level of precision (e.g., 2 for currency, 0 for whole numbers).
- Mode:
- Standard Round: Rounds to the nearest value (.5 rounds up).
- Floor (Down): Always rounds toward negative infinity.
- Ceil (Up): Always rounds toward positive infinity.
- Truncate: Simply removes digits beyond the specified precision without rounding.
Outputs
- Result: The formatted number according to your selected precision and mode.
Chart
- N/A: This tool provides direct numeric precision results.
“Good to Know”
- Ceil vs. Floor: These terms come from computer science. “Ceiling” always pushes a number up to the next possible value, while “Floor” always drops it down.
- Rounding to Zero: If you set Decimal Places to 0, you will effectively turn any decimal into a whole number.
- Scientific Use: In science, rounding is often used to match the “significant figures” of a measurement.
Examples
Example 1: Standard Currency
- Input: Number: 19.995, Decimals: 2, Mode: Round
- Output: 20.00
Example 2: Inventory Planning (Ceil)
- Input: Number: 12.1, Decimals: 0, Mode: Ceil
- Output: 13 (Useful when you must buy a full unit for any fractional need)
Example 3: Truncating Data
- Input: Number: 1.2399, Decimals: 2, Mode: Trunc
- Output: 1.23