Find out the length of the area. If you do not have this information, use the tape measure.
Find out the width of the space.
Multiply length times width to calculate the square footage. For example, if your space is 10 feet by 12 feet, your room's square footage is 120.
Multiply the square feet figure by 1.5. This is the standard formula to discover how much wattage your space will need. In our example, the square footage of the room is 120. Multiply 120 by 1.5 to determine that you will need 180 watts of light--whether from table lamp, desk lamp, or ceiling fixture--to light the room adequately.
Things You Will Need
- Measuring tape
- Once you have discovered how much general light your space needs, a lighting designer or contractor can help you fine-tune your lighting scheme.