Rounding Calculator

Round numbers to any decimal place, significant figures, or nearest whole number. Choose from various rounding methods including standard, banker's, and truncation.

Enter Number

Quick Examples:

Rounding Methods Explained

1. Standard Rounding (Round Half Up)

The most common rounding method. When the digit to be rounded is exactly 5, round up to the next higher number.

2.4 → 2 (round down)
2.5 → 3 (round up)
2.6 → 3 (round up)

2. Banker's Rounding (Round Half to Even)

When the digit is exactly 5, round to the nearest even number. This reduces bias in statistical calculations.

2.5 → 2 (round to even)
3.5 → 4 (round to even)
4.5 → 4 (round to even)

3. Ceiling (Always Round Up)

Always round up to the next higher integer, regardless of the decimal value.

2.1 → 3
2.9 → 3
-2.1 → -2

4. Floor (Always Round Down)

Always round down to the next lower integer, regardless of the decimal value.

2.1 → 2
2.9 → 2
-2.1 → -3

5. Truncation

Simply remove the decimal places without any rounding. Always moves toward zero.

2.1 → 2
2.9 → 2
-2.9 → -2

How to Use This Calculator

1
Enter Your Number
Input any decimal or whole number. You can use scientific notation (e.g., 1.23e-4).
2
Choose Rounding Method
Select from standard, banker's, ceiling, floor, or truncation methods.
3
Set Precision
Choose to round to decimal places, significant figures, or nearest values.
4
View Results
See the rounded result, comparison with original, and step-by-step process.

Applications of Rounding

Financial Applications

  • Currency calculations (round to 2 decimal places)
  • Tax calculations and reporting
  • Interest rate computations
  • Budget planning and estimates
  • Accounting and bookkeeping
  • Price calculations in retail

Scientific Applications

  • Measurement precision and accuracy
  • Statistical analysis and reporting
  • Engineering calculations
  • Laboratory data processing
  • Quality control measurements
  • Research data presentation

Example Calculations

Example 1: Rounding to 2 Decimal Places

Original: 3.14159
Standard: 3.14 (4 < 5, round down)
Banker's: 3.14 (4 < 5, round down)
Result: 3.14

Example 2: Rounding to 3 Significant Figures

Original: 1234.567
Identify: 1, 2, 3 are first 3 significant figures
Next digit: 4 < 5, round down
Result: 1230 (or 1.23 × 10³)

Example 3: Banker's Rounding vs Standard

Original: 2.5
Standard: 3 (round half up)
Banker's: 2 (round half to even)
Original: 3.5
Standard: 4 (round half up)
Banker's: 4 (round half to even)

Frequently Asked Questions

When should I use banker's rounding instead of standard rounding?

Banker's rounding is preferred in financial and statistical applications because it reduces bias. When rounding many numbers, standard rounding tends to round up more often, while banker's rounding balances upward and downward rounding.

What's the difference between significant figures and decimal places?

Decimal places count digits after the decimal point, while significant figures count all meaningful digits. For example, 0.00123 has 5 decimal places but only 3 significant figures.

How do I round negative numbers?

The same rounding rules apply to negative numbers. For example, -2.5 rounds to -3 with standard rounding (away from zero) and -2 with banker's rounding (to even). Floor always rounds toward negative infinity, while ceiling rounds toward positive infinity.