Round, ceil, floor numbers and add thousand separators
Round and format numbers in various ways
Rounding is a method of approximating a number to a specified number of digits. Round rounds to the nearest value (up if 5 or more), Floor always rounds down, and Ceil always rounds up.
Can be used in financial calculations, tax calculations, measurement adjustments, statistical data processing, price display, grade calculations, and more.
Round (반올림) rounds up when the digit is 5 or more, and down when 4 or less. Ceil (올림) always rounds up to the larger number, while Floor (버림) always rounds down to the smaller number. For example, 2.5 becomes 3 with round, 3 with ceil, and 2 with floor.
Banker's Rounding rounds 5 toward the nearest even number. For example, 0.5 rounds to 0 and 1.5 rounds to 2. This method is widely used in finance and science to reduce accumulated rounding errors when processing large amounts of data.
This calculator supports 0 decimal places (integers) up to 10 decimal places. 2–4 places are most commonly used in general calculations, while more places may be needed for scientific calculations.
In Excel, use ROUND(number, digits) for rounding, ROUNDUP for ceiling, and ROUNDDOWN for floor. For example, =ROUND(3.456, 2) returns 3.46. The INT function truncates decimals to an integer, while TRUNC removes decimal places for all numbers including negatives.
Understand and correctly apply the rounding methods commonly used in mathematics and real-world practice.
Rounding is the process of approximating a number to a specified number of digits. The most common method — round half up — follows the rule of rounding up when the digit is 5 or more, and down when it's 4 or less. Ceiling (ceil) always rounds up, while floor always rounds down. In tax calculations, floor is often used to favor the taxpayer, while ceil is used in inventory counting to ensure sufficient stock.
Rounding is critically important in financial calculations. The choice of rounding method can affect results in interest calculations, currency conversions, and tax computations. In data analysis and statistics, rounding plays a key role in maintaining the significant digits of measured values and presenting numbers readably in reports. Scientific calculations use rounding in conjunction with the concept of significant figures.