How much paint would i need for my bedroom ?

Question

about how many gallons of paint for 2 walls about 15ft by 8ft

and how mant gallons for 2 walls of 10-1/2 ft by 8ft

im using 2 different color paint for room . so that why i put that sepratly

....

do i need to paint my room white before i put the colors i want it ?

Answer 1

You can calculate this yourself.

Figure out the area.  Add up the walls plus the ceiling.  Add for how many coats.  Most paints cover about 350 to 400 square feet per gallon.

Figure for your two colors. (So I get something like 15x8x2x# of coats for the one, and 10.5x8x2x# of coats for the other, plus whatever you want to do for the ceiling.  Divide each by 300 to get the gallons of each color with a margin of safety and still have some left over for touchups later.)

Unless there is some problem, you should not need to prime the wall with the white first.  If it is unsealed new gypsum board or plaster, then yes, use a primer.  Otherwise, most modern paints cover just fine.  You can also ask at the paint store, telling them what color(s) you are covering with what.

Buy flat finish for your walls, and if you have windows or doors for which to paint trim, buy a satin finish for these, either in a matching color, or in another color, if you like contrast.

Have fun -- new paint is so transformative!

Answer 2

If you have to buy a gallon then a gallon each for two coats. Remember to leave the paint overnight to dry before painting the next coat. It gives a better finish.  

Answer 3

You'll need to paint the room twice, i.e. 2 coats for each colour. If you check on  the paint can, it says how much paint you'll need for a certain area. It varies btw different paints. Multiply w 2 and you know how much paint to buy.

You don't need to paint the room white first unless you're moving from a very dark (read: black, midnight blue etc) colour to a very bright one. Then you may need to paint it 3 times, depending on how good the paint is.