FLOOR.MATH Function – Google Sheets

The FLOOR.MATH function in Google Sheets rounds a number down to the nearest integer multiple of a specified significance. Depending on the mode setting, you can round negative numbers toward or away from zero.

FLOOR.MATH and FLOOR.PRECISE are intended to supplant the FLOOR function.

Syntax

=FLOOR.MATH(number, [significance], [mode])

number – The number for the function to round

significance – Optional. The multiple to round down to. The default value is 1.

mode – Optional. The rounding direction for negative numbers. This has no impact on positive numbers.

  • 0 – Round away from zero
  • 1 – Round toward zero

Similar Functions

Several functions deal with rounding. Choose the most appropriate for your use.

  • CEILING.MATH – Rounds a number up to the nearest integer multiple of specified significance with customizable negative number treatment
  • CEILING.PRECISE – Rounds a number up to the nearest integer multiple of specified significance
  • INT – Rounds a number down to the nearest integer
  • FLOOR.MATH – Rounds a number down to the nearest integer multiple of specified significance with customizable negative number treatment
  • FLOOR.PRECISE – Rounds a number down to the nearest integer multiple of specified significance
  • MROUND – Rounds a number to the nearest multiple of another number
  • ROUND – Rounds a number to a specified number of decimal places using standard rounding
  • ROUNDDOWN – Round a number down to a specified number of places
  • ROUNDUP – Round a number up to a specified number of places
  • TRUNC: Truncates a number to a certain number of significant digits by omitting less significant digits

Possible Errors

#VALUE! – An argument is non-numeric.

Insert Math Symbols (Add-On)

Web banner showing math symbols from the Insert Special Characters Add-On
Insert Any Math Symbol with One Click

Examples

You can use FLOOR.MATH in many different ways. Let’s take a look at a few, starting with rounding currency.

Example 1 – Round Down to the Next Nickel

Sometimes, presenting a price rounded down to the next nickel looks more attractive to a customer. Let’s look at how to do that.

The FLOOR.MATH function rounding currency to the nearest nickel
Rounding Down to the Next Nickel

The formula used in cell C2: =FLOOR.MATH(A2,B2)

We use the FLOOR.MATH function to round the Original Price to a significance of $0.05. Since the function rounds down, it rounds $1.23 to $1.20 in row 2 and rounds $1.27 down to $1.25 in row 4. Google Sheets does not round the value in row 3 because it is already a multiple of $0.05.

Example 2 – Round Down to the Nearest Half-Hour

Next, let’s round some time values. It is common to refer to a time as a rounded value. In this example, we’ll round values down to the previous half-hour.

The FLOOR.MATH function rounding times to the nearest half hour
Rounding Down to the Next Half Hour

The formula used in cell C2: =FLOOR.MATH(A2,B2)

⚠️ You can enter a half hour as “0:30” or “0:30:00“. Either way, you’ll need to use custom formatting to remove the seconds, like in the example above in column B.

Rows 2 and 4 both get rounded down to the last half hour. As 1:30 PM is already a multiple of 30 minutes, the FLOOR.MATH function does not change the time in row 3.

Example 3 – Round With Different Significances

Up to this point, we have been changing the number. Now, let’s look at changing the significance. We’ll use positive and negative significances to see the differences.

The FLOOR.MATH function rounding numbers using different significances
Rounding Using Different Significances

You can see that positives move toward zero while the negatives move away from zero. If you want negative values to move toward zero, you must change the value of the mode argument. Let’s look at that in the following example.

Example 4 – Rounding Negative Numbers with Different Modes

In previous examples, we did not specify a value for the mode argument. Now, we will use it to tell the function in which direction to round negative values.

The FLOOR.MATH function producing different results using different modes
Rounding Using Different Modes

In rows 2 through 4, the mode of 0 makes the function round negative values away from zero. Specifying a mode of 1 (or anything other than 0) moves the values toward zero in rows 5 through 7.

Live Example in Sheets

Make a copy of this spreadsheet to get the examples in your Google Sheet.