How to Round to the nearest whole number in C#

See the official documentation for more. For example:

Basically you give the Math.Round method three parameters.

1. The value you want to round.
2. The number of decimals you want to keep after the value.
3. An optional parameter you can invoke to use AwayFromZero rounding. (ignored unless rounding is ambiguous, e.g. 1.5)

Sample code:

var roundedA = Math.Round(1.1, 0); // Output: 1
var roundedB = Math.Round(1.5, 0, MidpointRounding.AwayFromZero); // Output: 2
var roundedC = Math.Round(1.9, 0); // Output: 2
var roundedD = Math.Round(2.5, 0); // Output: 2
var roundedE = Math.Round(2.5, 0, MidpointRounding.AwayFromZero); // Output: 3
var roundedF = Math.Round(3.49, 0, MidpointRounding.AwayFromZero); // Output: 3

Live Demo

You need MidpointRounding.AwayFromZero if you want a .5 value to be rounded up. Unfortunately this isn't the default behavior for Math.Round(). If using MidpointRounding.ToEven (the default) the value is rounded to the nearest even number (1.5 is rounded to 2, but 2.5 is also rounded to 2).

Math.Ceiling

always rounds up (towards the ceiling)

Math.Floor

always rounds down (towards to floor)

what you are after is simply

Math.Round

which rounds as per this post

You need Math.Round, not Math.Ceiling. Ceiling always "rounds" up, while Round rounds up or down depending on the value after the decimal point.