Ceiling / Floor vs. Roundup / Rounddown

[Justinian]

What is the actual difference between ceiling and roundup, floor and rounddown?

 

[Yard]

CEILING and FLOOR round to a given multiple. ROUNDUP and ROUNDDOWN round to a given number of decimal places.

 

[Justinian]

CEILING and FLOOR round to a given multiple. ROUNDUP and ROUNDDOWN round to a given number of decimal places.

Ok, so if I were to create a spreadsheet that calculates postage increases in increments of 0.5 ounces, would I use roundup?

 

[Yard]

e.g.

=CEILING(10.2,0.5)

returns 10.5.

=ROUNDUP(10.2,1)

returns 10.3

and

=ROUNDUP(10.2,0)

returns 11.

Just give it a try!

 

[Justinian]

e.g.

=CEILING(10.2,0.5)

returns 10.5.

=ROUNDUP(10.2,1)

returns 10.3

and

=ROUNDUP(10.2,0)

returns 11.

Just give it a try!

Cool, thank you!

 

[ssjseifer]

e.g.

=CEILING(10.2,0.5)

returns 10.5.

=ROUNDUP(10.2,1)

returns 10.3

and

=ROUNDUP(10.2,0)

returns 11.

Just give it a try!

As a point, there is another difference between the functions in that, in relation to a numberline, FLOOR() will typically round down accurately to the left, and CEILING() will round up to the right. ROUNDDOWN(), however, will round towards zero and ROUNDUP() will round away from zero.

ROUNDDOWN(2.5) = 2
FLOOR(2.5) = 2
ROUNDDOWN(-2.5) = -2
FLOOR(-2.5) = -3

ROUNDUP(2.5) = 3
CEILING(2.5) = 3
ROUNDUP(-2.5) = -3
CEILING(-2.5) = -2

Meanwhile, ROUND() will ROUNDDOWN() if the decimal is less than .5, otherwise it will function as ROUNDUP():
ROUND(2.5)=3
ROUND(-2.5)=-3

 

[zeiss74]

As a point, there is another difference between the functions in that, in relation to a numberline, FLOOR() will typically round down accurately to the left, and CEILING() will round up to the right. ROUNDDOWN(), however, will round towards zero and ROUNDUP() will round away from zero.

You are 9 years late to the party, but that's a cool detail to know!