Ceiling Function Calculator

Use our ceiling function calculator to round a number up to the nearest integer (or to a chosen multiple). Includes the ceiling function definition, ceiling function formula, a ceiling function equation, a ceiling function example, and the ceiling function in Excel.

x
Any real number.
Results
Ceiling of x
The smallest integer greater than or equal to x (⌈x⌉).
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What is the Ceiling Function?

The ceiling function rounds a number up to the nearest integer. It’s written as ⌈x⌉ and is sometimes called “round up” in math.

If x is already an integer, the ceiling of x is x itself. If x is not an integer, the ceiling function returns the next integer greater than x.

This ceiling function calculator can compute ⌈x⌉ and can also be used like a ceiling function Excel setup when you want to round up to a specific multiple.

Ceiling Function Formula

The ceiling function is the smallest integer greater than or equal to x. You’ll often see this written as a ceiling function equation using brackets.

Ceiling function =
⌈x⌉ = smallest integer x

This is the core ceiling function formula.

Ceiling to a multiple (optional) =
ceil(x, m) = ⌈x / m⌉ · m

Rounds x up to the nearest multiple of m (useful for pricing, packing, time blocks, etc.).

x
= Input number
⌈x⌉
= Ceiling of x (rounded up to an integer)
m
= Multiple to round up to (optional)
Ceiling function example (positive)
⌈3.14⌉ = 4

3.14 is between 3 and 4, so ceiling rounds up to 4.

Ceiling function example (negative)
⌈-2.7⌉ = -2

Ceiling rounds up toward positive infinity, so -2.7 goes to -2.

How to Use the Ceiling Function Calculator

  1. 1

    Enter the number x.

  2. 2

    The calculator returns ⌈x⌉, the ceiling value (rounded up to the nearest integer).

  3. 3

    If your tool supports a multiple, enter m to round up to the nearest multiple of m.

  4. 4

    Use the result for rounding, grouping, scheduling, or any situation where you need a ceiling function equation output.

Frequently Asked Questions

What is the ceiling function formula?

⌈x⌉ is the smallest integer greater than or equal to x.

What is a ceiling function example?

⌈4.01⌉ = 5, and ⌈-1.2⌉ = -1.

How is ceiling different from rounding?

Ceiling always rounds up to the next integer (or multiple), while rounding goes to the nearest value based on the decimal part.

What is the ceiling function equation notation?

It’s written with ceiling brackets: ⌈x⌉.

How do I use the ceiling function in Excel?

Excel has CEILING and CEILING.MATH. Example: =CEILING.MATH(A1) rounds A1 up to an integer. To round up to a multiple: =CEILING.MATH(A1, m).

Does the ceiling function work for negative numbers?

Yes. It rounds up toward positive infinity. For example, ⌈-2.7⌉ = -2.