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How To Calculate Amount of Paint Required ? November 1, 2008

Posted by admin in : Painting Tips , trackback

 

Paint Calculation

  

If your project is small enough, like painting a grille, or touching-up a couple of nail holes, you never have to worry how much paint you would need to buy. Just purchase the smallest pack and you’ll still have some leftovers. When the projects get bigger, you would need to come up with a good estimate. Otherwise, you may end up with way too much, which can be quite costly, or too little, which can be equally costly especially if you have half a dozen workers having an unscheduled "tea-break" while you "top-up".

To calculate the amount of paint required for a particular project, you would need to known basically 2 pieces of information :

  1. the area to be painted and
  2. the coverage of the paint

 

How to calculate the area to be painted?

 

a) Walls - Multiply the length and height of the wall to get the area.

 

b) Room - Add up the areas of all the walls of the room

c) Doors - Multiply the breath and height of the door and double it (for painting on both sides)

d) Cylindrical Pipes - Measure the diameter and the length of the pipe and use the following formula:

                                   Diameter x Length x 3.14

 

How do I obtain the coverage of the paint?

The coverage of the paint can be found on the product datasheet (also called technical datasheet or product specification). The way it is presented varies with company. Below is an example of Nippon emulsion paint:

 

The above shows that the theoretical coverage of this paint is 13 sq m / litre at 30 micron DFT (dry film thickness). In other words, one litre of paint can cover 13 square metres if painted at a dry film thickness of 30 microns.

 

Putting It All Together

Dividing the area to be painted by the coverage, we will arrive at an amount of paint required in litres. For example, if the area of a room is 48 sq metres and the coverage is 13 sq metres per litre, then the amount of paint needed is 48/13 or 3.7 litres. Add 20% loss factor and you’ll arrive at 4.44 litres. Remember that this is for one coat. Double it if you need to paint 2 coats.

 

Some Tips and Shortcuts

1) In our local context, a HDB room usually requires one can of 5-litre emulsion paint. Living rooms of 4-rooms and above usually need 2 cans.

2) If you do not have access to datasheets, use 8-10 sq m per litre for emulsion paint and 12 - 14 sq m per litre for oil-based paint. This does not work for industrial paints which can vary quite a lot.

3) Rockstone surfaces would require more paint and may need up to 50% more for rougher grains.

4) If the area to be painted is in square feet, multiply it by 0.093 to arrive at the equivalent in square metres.

 

Hope this post helps you in calculating the amount of paint needed to get that paint job done. However,  amount calculated can still vary depending on painting technique, equipment used and surface profile.

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2. Ashok - November 11, 2008

Hi,

I wanted to know about industrial paint system,which i have to paint for steel structurals.Please let me know how to calculate the amout of paint required if i have a area in square meters(8500 square meter) & DFT may be 40,50 microns 2coat systems.
How much wastage factor i have to consider.

3. admin - November 12, 2008

Ashok,
We normally add a 20% loss factor.
You would need to have the practical coverage for the paint you are using and this can be found on the technical datasheet for the paint. If you give me this number and the DFT of the paint, I can show you the calculation. Regards.

4. mr kenneth greenhow - November 18, 2008

could u give me step by step infomation on the question below

question how much paint would be required to paint the external surface of a 4 meter diameter circular cylinder standing 7 meters in height? the flat circular top of the cylinder must also be painted. the paint to be used is solvent free and the surface of the cylinder has been wire brushed. the dft required is 130um

5. admin - November 20, 2008

Kenneth,
Need to know the coverage of the paint. Different types of paint have different coverage and this may vary quite a bit. The coverage information is usually found on the product technical datasheet.
Regards.

6. Brenda Phipps - October 13, 2010

Hello, I was wondering if you could help me with how much paint is required for 14,000 sq ft of brick wall that was painted previously.We will be using sprayer and rollers to apply. Thank you for your attention to this matter!:>)

7. Vasudev Akundi - February 1, 2011

The theoretical spreading rate or TSR of a paint is given by multiplying the volume solids percentage of that particular product with 10 and dividing the product by the required dry film thickness or DFT. For example a particular paint has a volume solids percentage of 50% and the required DFT is 100 microns then the theoretical coverage is given by 50 x 10 / 100 = 5 Square meters / litre. However the practical coverage depends on the structure to be painted, method of application, ambient conditions during application, condition of the surface to be painted etc. If you want to quote for a industrial painting work, calculate the amount of paint according by dividing the total area by the TSR and then double the quantity. This will leave you safe on the consumption front.

8. AFOLABI SUNDAY CHARLES - June 1, 2011

thank you sir you av rely answer my question

9. SATYA - August 8, 2011

HELLO SIR,

WE HAVE A TOTAL AREA OF 1000 SQUARE FEET PLOT . I WANT TO KNOW DIFFERENT KIND OF PAINT AVAILABLE IN MARKET FOR INTERIOR AND EXTERIOR PAINT.HOW MUCH PAINT WILL BE REQUIRED TO PAINT A HOUSE WITH A TOTAL OF 7-8 NUMBER OF ROOM

10. yuki - November 5, 2011

Anybody know how to calculate 3 room HDB NG paints required?

11. sankar - November 18, 2011

all exterior & interior paint consumption detail required to me then explain how to calculate paniting consumpution method

12. Dhananjay Kumar - December 2, 2011

Sir,
I need the calculation for the paint consumption for industrial paint , for painting of truss having different sections of angles and chanels, plates etc.The consumption may be given in per MT for 30 microns DFT

13. ABHINAV GOGIA - December 3, 2011

all exterior & interior paint consumption detail required to me then explain how to calculate paniting consumpution method .
AND HOW TO TAKE ESTIMATE STEP WISE COSTING WHILE PUTTING THE PINT INTERIOR OR EXTERIOR

14. Chris Perera - December 19, 2011

How many liters of briliant white emulsion paint you require to apply for inside walls of (12 x 10 Square metrers) from 1 liter how many square meter and square foot can be applied please.

Can you please give the answer for the weather shield for outside as well.

If you have a calculator chart can you please send me.

Thanks

Many thanks.