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Red Light Therapy Treatment Time Calculator

Enter Power Density and Joules to Get Your Treatment Time in Seconds

If you know what you’re doing, here’s the calculator directly below. If you don’t know what you’re doing, keep reading!

Instructions for Getting Your Treatment Time Based on Your Goals and Device Power

You can use tools on this site to determine everything you need about your dose and treatment time. This post will show you how.

Get These Red Light Ducks in a Row

You will need these numbers to calculate your treatment time each day. These will give you the treatment time in seconds using the calculator at the bottom of this article. I will show you how to get these values.

  1. one-third the manufacturers’ stated red light output power density
  2. the target wavelength for your wellness goal
  3. the target energy for your wellness goal

Get the Light’s Output Power Density

Find the manufacturer’s  output density for your device. This is usually stated like this:

100 mW/cm^2 at 6 inches

That is, the device will output 100 milliwatts of power per squared centimeter if the device is 6 inches from the target. So before you continue, how far away will you be from the device? You’ll be zero inches away if the light is right on your body. Otherwise use a number that the manufacturer gives you, which will probably be 6 inches or 12 inches. Pick one distance and stick with it. Distance is hugely important to getting the right dose.

Let’s say the manufacturer says the power density at 6 inches is 100 mW/cm^2. Their instructions will look like this:

Power Density is 100 mW/cm^2 at 6 inches

If you trust the vendor, then use the 100 mW. For most devices on the market, the real value will be about one third of the stated value. Handicap the power density by one third. Divide by three to get the value we’re going to use.

handicap the overstated power density, so:
100 mW / 3 = 33.33 mW

Our real power density is now:

power density we are using for our treatment calculation:
33 mW/cm^2  at 6 inches

Get the Treatment Goal Target Wavelength

Each ailment responds to a specific wavelength and a specific amount of energy. Read this wavelength instruction and the energy instruction below before proceeding.

You can use the tool I’ve created to find the wavelengths that have had good results for your target wellness goal. I have documented successful red light experiments for you to look up. Go to the Light Dose Database (opens in a new window), and select your goal. The results will include the wavelengths the study authors used when they achieved good results for your ailment.

Look for “nm,” which is the wavelength in nanometers. This is your target wavelength. It is almost always in the infrared range between 750 nm and 1000 nm. That’s because the infrared wavelengths can penetrate to the body’s tissues. The 600+ nm wavelengths are more effective for skin issues. If your light is both a 600+ and an infrared light combined, then double the treatment time for internal issues such as arthritis.

The studies test different wavelengths and energies, so you’re going to have to take an educated guess. For example, the arthritis studies were successful with wavelengths mostly in the 800-950 nm range. Therefore you want a light that emits a wavelength in this range.

In our example, the target wavelength in nanometers is in the infrared range. For this example, we’ll say that the light is purely 830 nm, with no other wavelengths. If your light emits between 750-1000 nm, go to the next step. If it emits a 600+ nm as well as a 750-1000 nm wavelength, then you will need to double whatever treatment time you get.

If it emits only 600+ and no wavelengths in the 750-1000 range, then the light might be less likely to work for your ailment. But it doesn’t mean it won’t work.  Many studies have supported the use of red (as opposed to infrared) wavelengths. The 600+ nm range might work, and you should give it a try if all you have to lose is some time.

Get the Treatment Goal Target Energy

In the database results, look for the “J” value. This is the energy applied to the target area in the study. “J” is the energy value in joules. Find the “J” values in the results. Use something in the middle to the top of the range.

For example, let’s say you find five studies for your wellness goal. Those studies used 1 J, 10 J, 20 J, 30 J, and 40 J energy. The average is about 20 J, and you want to tend to ward the top of the range. So for this example, you can use 30 J or 40 J in your treatment. Let’s use 30 J for our example.

Use the Calculator to Determine Your Treatment Time

Now we have the values we need to deterine the treatment time each day. In our example, the manufacturer says that the light emits 100 mW/cm^2  at 6 inches. We know that’s over stated, so we take a third of that value. We will use the light at 6 inches, but assume 33 mW/cm^2 rather than 100 mW/cm^2.

Enter 33 for milliwatts

We have the target energy in joules for your goal, based on successful studies on humans for your treatment goal. We saw that 1, 10, 20, 30 and 40 joules were all successful. We take the middle to high end of these values.

Enter 30 for joules

When you enter the milliwatts and joules, the calculator will give you the treatment time in seconds, and then that same value in minutes. Do one treatment per day to give your body time to absorb and use the light before treating yourself again.

Photo by Myicahel Tamburini from Pexels