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Quick guide

What This Calculator Does

This rounding calculator compares what happens to the same number under different rounding rules. Enter a number, choose a mode, and set the decimal precision to see the original value, the rounded result, and the difference caused by the rule.

The page has five actual modes: round, ceil, floor, trunc, and bankers. It is useful for report formatting, programming, classroom work, data cleanup, and result verification. For percentage changes, use the percentage calculator; for decimal and fraction conversion, use the decimal-fraction converter.

When to Use It

  • You need to display a number to 0 through 10 decimal places.
  • You want to compare round, ceiling, floor, and truncation behavior.
  • You want to understand why negative numbers differ under floor and trunc.
  • You want to test banker's rounding on midpoint values such as 2.5 and 3.5.
  • You want to inspect the rounding difference instead of seeing only one final number.

Inputs Explained

Number

Enter the finite numeric value to process. Positive, negative, and decimal values are supported. Negative values are especially useful because they make number-line direction and toward-zero truncation easy to see.

Rounding Mode

The page provides five modes:

Read the full guide

Frequently Asked Questions

Which rounding modes does this tool support?

It supports round, ceiling, floor, truncation, and banker's (half-to-even) rounding.

How many decimal places can I choose?

The page supports 0 through 10 decimal places. At 0, the rule is applied at the whole-number level, and the display keeps the selected number of trailing zeros.

Why do floor and truncation differ for negative numbers?

Floor always moves toward negative infinity, while truncation moves toward zero, so -2.37 at one decimal place becomes -2.4 and -2.3 respectively.

How is round different from banker's rounding?

Round follows JavaScript Math.round for nearest values, including its exact-half behavior; banker's rounding chooses the even endpoint at a midpoint.

Can this replace a financial system's formal rounding rule?

No. It is useful for learning, development, and verification; formal settlement should follow your accounting rule, contract, or system implementation.

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Rounding Calculator

Round to 0-10 decimal places with round, ceiling, floor, truncate, and banker's modes, and view the original value and difference.

🔄

Number Rounding Calculator

📊Results

Original Number
0
Rounded Result
0.00
Difference
0.00
💡

Round

Round to nearest decimal place

Rule comparison

InputRoundBankers
2.532
3.544
4.554
-2.5-2-2