Grow Room Cost Calculator (FREE Tool)

This grow room electricity calculator will help you understand the cost of electricity while growing cannabis.

Electricity consumption is an important consideration when budgeting for your grow.

Most growers have no idea how to budget for their electricity because calculating it is confusing.

That’s why I decided to create this simple calculator, that allows you to see how much you are likely to spend on your electricity over the course of your grow.

Free Cannabis Seeds? Check out my list of the best seed bank promotions – Including FREE Seeds, discount codes, and giveaways!

How Does The Calculator Work?

The grow room electricity calculator uses the following equation to calculate the cost of electricity during your grow:

Cost of Electricity x Number of Hours x (Watts / 1000) = Total Cost

Let’s take a look at each part of the equation:

Cost of Electricity

This is the cost of electricity that you pay and you can usually find it on your bill.

It’s measured in kWh.

However, if you can’t find this, you can use the national average to get a rough idea, which is $0.12 in the USA and $0.10 in Canada.

Number of Hours ( for vegetative and flowering )

This is the number of hours that you will be running your electrical appliance every day.

During the Vegetative stage, most growers opt to keep their grow lights on for 18 hours and then switch them off for 12 to give the plants a rest.

However, some growers like to leave their lights on for 24 hours every day as it speeds up the vegetative growth – just be mindful that this light-dark cycle will increase your electricity bill.


This is the number of watts that your electrical appliance draws from the wall.

This could be your grow light, a rotating desk fan, or exhaust that’s sucking the air out of your grow tent.

This value is then divided by 1000 to convert the number of watts used to KiloWatts (kW)

Important: when adding the wattage from an LED grow light, make sure that you use the actual number of watts that the light draws from the wall and not the total number of watts in the LED chips. The correct value is usually displayed by manufacturers like this: “consumes X number of watts”

Final thoughts

So there we have it, a simple way to estimate the cost of electricity during your grow.

I hope you found this grow room electricity calculator useful.

If you did, please let me know in the comments below!

James Alexander James Alexander
Hey, I'm James! The founder and head writer here at I started this site to share my passion and knowledge of all things cannabis. I used to work as a budtender in central Amsterdam, and have over 7 years of growing experience.

Find me online:

3 thoughts on “Grow Room Cost Calculator (FREE Tool)”

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.