round up formula help

[david graham]

I need a formula that will round the value of a cell up in increments of 15.

So, if cell a1 = 14, cell b2 should round it up to 15.

If cell a1 = 16, cell b2 should round it up to 30.

If cell a1 = 27, cell b2 should round it up to 45.

anyone know how to represent this in a formula?

 

[c_m]

=ceiling(a1,15)

 

[david graham]

Thanks