I couldn’t find a decent article outlining the differences between the various rounding functions in Excel… so I thought I’d create one.

Some functions will round to a set number of decimals, others just drop the fraction part completely. There are also some differences when working with **negative** numbers.

We’ll look at the following five different functions:

### INT

Syntax:

=INT(number)

Returns the integer (non-fraction part) of a number, but always rounds to the “smaller” integer. So **INT(3.6)=3** and **INT(-3.6)=-4**.

Something like **INT(-3.2)** would also round to **-4**.

So for positive numbers it behaves like ROUNDDOWN and for negatives it behaves like ROUNDUP.

### TRUNC

Syntax:

=TRUNC(number, [num_digits])

Also returns the integer of a number. But this time it doesn’t do any rounding, it just drops the fraction. E.g. **TRUNC(3.6)=3** and **TRUNC(-3.6)=-3**

Another difference is that you can provide a number to specify the precision of the truncation, e.g. **TRUNC(3.765, 1)=3.7** and **TRUNC(-3.765, 1)=-3.7**

If you leave the precision out it just drops the entire fraction.

### ROUND

Syntax:

=ROUND(number, num_digits)

Rounds a number to a specified number of digits. Specifying the precision is compulsory, so if you want to round to the nearest integer use **0** for num_digits.

Here are a few examples:

**ROUND(3.76, 0)=4** and **ROUND(-3.76, 0)=-4**.

**ROUND(3.76, 1)=3.8** and **ROUND(-3.76, 1)=-3.8**.

**ROUND(3.725, 1)=3.7** and **ROUND(-3.725, 1)=-3.7**.

### ROUNDUP

Syntax:

=ROUNDUP(number, num_digits)

Rounds a number up to a specified number of digits.

Examples:

**ROUNDUP(3.6, 0)=4 **and** ROUNDUP(-3.6, 0)=-4**

**ROUNDUP(3.2, 0)=4 **and** ROUNDUP(-3.2, 0)=-4**

This is a confusing one. Rounding a negative number “up” means going from -3.2 to -4 even though the value is getting smaller.

### ROUNDDOWN

Syntax:

=ROUNDDOWN(number, num_digits)

Rounds a number down to a specified number of digits.

Examples:

**ROUNDDOWN(3.6, 0)=3 **and** ROUNDDOWN(-3.6, 0)=-3**

**ROUNDDOWN(3.2, 0)=3 **and** ROUNDDOWN(-3.2, 0)=-3**

Again a confusing one. Rounding a negative number “down” means going from -3.6 to -3 even though that means the value is getting larger.

I hope this helps. If you have a scenario that you can’t quite work out from the examples above, get in touch and I’ll see if I can shed some light on the problem.