Rounding Calculator

About Rounding

Rounding is the process of replacing a number with an approximation that has fewer significant digits. Different rounding modes are appropriate for different contexts. Standard rounding (half-up) is the most familiar and taught in schools, while banker's rounding (half-even) is preferred in finance to eliminate systematic bias.

Decimal Places vs Significant Figures

Decimal places count the digits after the decimal point (e.g., 3.14 has 2 decimal places). Significant figures count all meaningful digits starting from the first non-zero digit (e.g., 0.00314 has 3 significant figures). Scientists typically use significant figures to express measurement precision.

Rounding Modes Explained

Ceiling and floor always round in one direction regardless of the fractional part. Truncation drops extra digits without rounding. Half-up and half-down differ only when the dropped portion is exactly 0.5. Banker's rounding (half-even) rounds 0.5 to the nearest even number, which statistically produces less accumulated error over many rounding operations.