circumference = around
: Height x circumference
: then you take and divide
circumference by 3.14
: the you divide that answer
by 2
: then you X the answer by 2
: and then X that by 3.14 and
you have your answer
: for the top portion of the
cylinder
:
http://goldenglowpaints.com/PaintEstimator/SHAPE.htm
TRIANGLE,SQUARE,RECTANGLE,CYLINDER,SPHERE,CIRCLE
COVERAGE
FOR DIFFERENT SHAPES
TRIANGLE

To
find the number of sq.ft.
in
any shape triangle or 3 sided
surface, multiply the height by the
width and divide the total by 2.
40’
height
x 50’ width
1,000 sq.ft.
50’
2,000 sq.ft. 2 2,000


SQUARE

Multiply the base measurement
in
feet times the height in feet.
40’
40’
x 40’ = 1.600 sq.ft.
40’


RECTANGLE

Multiply the base measurement
in
feet times the height in feet.
20’
40’
x 40’ = 800 sq.ft.
40’


CYLINDER

When circumference (distance
around cylinder) is known, mul
tiply height by circumference.
157’ circumference
x 100’
height
15,700 sq.ft. 100’
157’
When diameter (distance across)
is
known, multiply diameter
by
3.1416. This gives circum
ference. Then multiply by height.
3.1416 157’ circumference
x 50
diameter x 100’ height
157.0800 feet 15,700 sq.ft.
NOTE: Figures do not include end
area. See circle.


SPHERE

To
find the number of sq.ft. of
a
sphere or ball, multiply the
diameter (distance across) by
itself and then multiply this
total by 3.1416. If you haven’t the
diameter, you can find it
by
measuring the circumstance
and
multiplying it by .31831.
50’
diameter 2,5000
x50’
diameter x 3.1416
2,500 7,854.0000 sq.ft.


CIRCLE

To
find the number of sq. ft.
In
a circle, multiply the diameter
(distance across) by itself and
then multiply this total by .7854
50’
50’
diameter 2,5000
x50’
diameter x .7854
2,500 1,969 sq.ft.


CHAIN LINK FENCES
Figure the square foot area as a solid and
double it to allow for both sides. For
spray, this will be fairly accurate since
overspray must be considered. For roller,
the coverage indicated in the product data
sheets should be increased.
WALLS 
When figuring the square foot area, openings
of less than 100 square feet should not be
deducted.
OPEN WEB
STEEL JOISTS
Original equipment manufacturers and
fabricators generally dip these joists, as a
first or shop coat. On all repaint work, by
spray, these manufacturers recommend the
paint be estimated by thinking of the joist
as a solid rather than open web. Double for
both sides.
STACKS
To compute the square foot area of a stack
multiply height (B) by the average diameter
(A) and multiply that total by 3.
EXAMPLE: Diameter of stack at the top – 5
feet.
Diameter of stack at the bottom – 15 feet.
( 2 /( 5 + 15)
Average diameter = 10 feet.
Height 60 feet.
60 x 10 = 600.
600 x 3 = 1800 square feet of surface area.
DOWNSPOUTS & GUTTERS –
Measure the circumference in inches. To
figure square feet, divide the circumference
by 12 and multiply by total length in feet.
Double this figure if the inside is to be
painted.
PICKET FENCE –
Multiply the height by the length and
multiply the result by four.
The following is
an approximate estimate over various
irregular surfaces.
*
ROUGH SAWED SIDING

275 sq. ft./gallon 
ASBESTOS SIDING (UNSEALED) 
250 sq. ft./gallon 
ASBESTOS SIDING (SEALED) 
350 sq. ft./gallon 
BOARD & BAT (SMOOTH) 
350 sq. ft./gallon 
BOARD & BAT (ROUGH) 
250 sq. ft./gallon 
SMOOTH SHINGLES 
275 sq. ft./gallon 
SHAKE SHINGLES 
200 sq. ft./gallon 
SMOOTH CONCRETE (UNSEALED) 
350 sq. ft./gallon 
SMOOTH CONCRETE (SEALED)

400 sq. ft./gallon 
CONCRETE BLOCK (UNFILLED) 
100 sq. ft./gallon 
CONCRETE BLOCK (FILLED) 
250 sq. ft./gallon 
HAYDITE BLOCK (UNFILLED) 
75 sq. ft./gallon 
HAYDITE BLOCK (FILLED) 
200 sq. ft./gallon 
STUCCO MEDIUM (UNSEALED) 
100 sq. ft./gallon 
STUCCO MEDIUM (SEALED) 
150 sq. ft./gallon 
STUCCO ROUGH (SEALED) 
75 sq. ft./gallon 
STUCCO ROUGH (SEALED) 
100 sq. ft./gallon 
BRICK SMOOTH (UNSEALED) 
150 sq. ft./gallon 
BRICK SMOOTH (SEALED) 
200 sq. ft./gallon 
BRICK ROUGH (UNSEALED) 
100 sq. ft./gallon 
BRICK ROUGH (SEALED) 
150 sq. ft./gallon 

*
Estimating Paint Requirements
Most
exterior products will average
400 to 450 square feet per
gallon on smooth surfaces.
However, some surfaces due to
irregularity or roughness of the
surface will take considerably
more paint. Reference the chart
below to get a good idea on the
amount of paint you will need.
Asbestos Siding
(Sealed) 
350 sq. ft. per
gallon 
Asbestos Siding
(Unsealed) 
250 sq ft. per
gallon 
Board & Bat (Rough) 
250 sq. ft. per
gallon 
Board & Bat (Smooth) 
350 sq. ft. per
gallon 
Brick (Rough Sealed) 
150 sq. ft. per
gallon 
Brick (Rough
Unsealed) 
100 sq. ft. per
gallon 
Brick (Smooth
Sealed) 
200 sq. ft. per
gallon 
Brick (Smooth
Unsealed) 
150 sq. ft. per
gallon 
Concrete Block
(Filled) 
250 sq. ft. per
gallon 
Concrete Block
(Unfilled) 
100 sq. ft. per
gallon 
Haydite Block
(Filled) 
200 sq. ft. per
gallon 
Haydite Block
(Unfilled) 
75 sq. ft. per
gallon 
Rough Sawed Siding 
275 sq. ft. per
gallon 
Shake Shingles 
200 sq. ft. per
gallon 
Smooth Concrete
(Sealed) 
400 sq. ft. per
gallon 
Smooth Concrete
(Unsealed) 
350 sq. ft. per
gallon 
Smooth Shingles 
275 sq. ft. per
gallon 
Stucco Medium
(Sealed) 
150 sq. ft. per
gallon 
Stucco Medium
(Unsealed) 
100 sq. ft. per
gallon 
Stucco Rough
(Sealed) 
100 sq. ft. per
gallon 
Stucco Rough
(Unsealed) 
75 sq. ft. per
gallon 

It is advisable
when estimating the square footage in the
average residence to include areas such as
windows, doors, etc. in the final figure.
Deduct these areas only when they comprise a
more than average percentage of the total
area.