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  4. Rounding Calculator

Rounding Calculator

Round numbers by place precision, fraction units, or significant figures — with multiple rounding modes.

General

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How it works

Rounding replaces a value with a simpler approximation. Choose precision (tenths through millions), a fraction unit (1/8, …), or significant figures, then pick a rounding mode.

round(value × 10^p) / 10^p · or nearest k/n

When to use

Use this tool when you need to: start with Precision for tenths/ones/tens. Use Fractions for ⅛-style rounding, and Settings-style modes for how halfway values are resolved.

How to use this tool

  1. Enter your values in the fields above.
  2. Review the formula and any mode options for your problem.
  3. Read the result and the step-by-step solution.

Start with Precision for tenths/ones/tens. Use Fractions for ⅛-style rounding, and Settings-style modes for how halfway values are resolved.

Frequently asked questions

What is the Rounding Calculator?
Rounding replaces a value with a simpler approximation. Choose precision (tenths through millions), a fraction unit (1/8, …), or significant figures, then pick a rounding mode.
How do I use the Rounding Calculator?
Enter the required values, then calculate. The Rounding Calculator shows results, formulas, and step-by-step work when available. No account is required.
What formula does the Rounding Calculator use?
round(value × 10^p) / 10^p · or nearest k/n

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Round to a place

Choose a precision level (tenths, ones, tens, …) and a rounding mode. Positive precision is digits after the decimal; negative rounds to tens, hundreds, and so on.

Try an example

How it works

What is rounding?

Rounding replaces a number with a shorter or simpler value that is close to it, based on a precision and a rounding rule. For example, rounding 2.7 to the nearest integer gives 3.

Rounding modes

Round to the nearest uses the closest value; ties go half away from zero. Round half up / half down resolve exact halfway cases toward +∞ or −∞. Ceiling always moves toward +∞; floor toward −∞. Half to even / odd (banker's-style ties) pick the even or odd neighbor. Half away from zero and half towards zero break ties by distance from zero.

Precision levels

Precision 1 = tenths, 2 = hundredths, 0 = ones, −1 = tens, −2 = hundreds, and so on. You can type a custom integer level from −12 to 12.

Rounding to fractions

Rounding to 1/n means finding the nearest multiple of 1/n (for example nearest ⅛). This is common for pipe sizes, bolts, and other fractional measurements.