Red Light Therapy Dose Chart: Minutes by Distance (Example Numbers)
Published October 2026. Updated October 2026.
Quick answer
A dose chart is a lookup table built from one formula: J/cm² = mW/cm² x seconds / 1000. Because a minute is 60 seconds, every 1 mW/cm² of irradiance adds 0.06 J/cm² per minute. Multiply the stated irradiance at your distance by 0.06 to get J/cm² per minute, then multiply by minutes. The charts below use the published AWA FX300 and FX500 irradiance figures. The targets in the second set of tables are example numbers for arithmetic only, not recommendations.
How this chart is built
Most online "dose charts" are screenshots with no formula behind them. This one shows the working. We took each published irradiance figure from the AWA irradiance specs guide and multiplied by 0.06. You can rebuild any cell yourself.
A dose chart answers a narrow question: if a device emits this irradiance at this distance, how much energy per square centimeter arrives in a given time? It does not answer how long you should run a session. Your manual and product page set that.
Step 1: J/cm² per minute for the FX300
| Distance | Stated irradiance (mW/cm²) | J/cm² per minute |
|---|---|---|
| 1 in | 220 | 13.2 |
| 2 in | 145 | 8.7 |
| 3 in | 116 | 6.96 |
| 6 in | 83.5 | 5.01 |
| 12 in | 43.3 | 2.598 |
At 6 inches the FX300 delivers about 5.01 J/cm² each minute, so 10 minutes is 50.1 J/cm². At 12 inches it is about 2.6 J/cm² each minute, so the same 10 minutes is 25.98.
Step 1: J/cm² per minute for the FX500
| Distance | Stated irradiance (mW/cm²) | J/cm² per minute |
|---|---|---|
| 2 in | 220 | 13.2 |
| 3 in | 197 | 11.82 |
| 4 in | 149 | 8.94 |
| 5 in | 121 | 7.26 |
| 6 in | 94 | 5.64 |
| 7 in | 91.1 | 5.466 |
| 10 in | 81.4 | 4.884 |
| 12 in | 73.8 | 4.428 |
| 15 in | 70 | 4.2 |
| 20 in | 58.6 | 3.516 |
The FX500 figures cover more distances, from 2 to 20 inches. The product page lists the working distance for sessions, and the irradiance by distance chart shows the same figures as a line chart.
Step 2: minutes needed for example targets, FX300
Here we work backwards. Pick a number of J/cm², divide by the rate, and you get minutes. The four targets below are example numbers for arithmetic only. They are not suggested doses.
| Distance | 10 J/cm² (min) | 20 J/cm² (min) | 30 J/cm² (min) | 40 J/cm² (min) |
|---|---|---|---|---|
| 1 in | 0.8 | 1.5 | 2.3 | 3 |
| 2 in | 1.1 | 2.3 | 3.4 | 4.6 |
| 3 in | 1.4 | 2.9 | 4.3 | 5.7 |
| 6 in | 2 | 4 | 6 | 8 |
| 12 in | 3.8 | 7.7 | 11.5 | 15.4 |
Step 2: minutes needed for example targets, FX500
| Distance | 10 J/cm² (min) | 20 J/cm² (min) | 30 J/cm² (min) | 40 J/cm² (min) |
|---|---|---|---|---|
| 2 in | 0.8 | 1.5 | 2.3 | 3 |
| 3 in | 0.8 | 1.7 | 2.5 | 3.4 |
| 4 in | 1.1 | 2.2 | 3.4 | 4.5 |
| 5 in | 1.4 | 2.8 | 4.1 | 5.5 |
| 6 in | 1.8 | 3.5 | 5.3 | 7.1 |
| 7 in | 1.8 | 3.7 | 5.5 | 7.3 |
| 10 in | 2 | 4.1 | 6.1 | 8.2 |
| 12 in | 2.3 | 4.5 | 6.8 | 9 |
| 15 in | 2.4 | 4.8 | 7.1 | 9.5 |
| 20 in | 2.8 | 5.7 | 8.5 | 11.4 |
Read down any column and the minutes grow as the distance grows, because irradiance falls. Read across any row and the minutes grow in a straight line with the target. That straight line is the whole formula.
Reading the chart: a worked example
Example numbers for arithmetic only: suppose you want to find how long the FX500 at 10 inches takes to reach 30 J/cm². The stated irradiance at 10 inches is 81.4 mW/cm². The rate is 81.4 x 0.06 = 4.884 J/cm² per minute. Then 30 / 4.884 = 6.1 minutes. The table above shows 6.1 in the 10 inch row and the 30 J/cm² column.
Quick sanity checks for your own numbers
Before you trust any cell, run a head check. Doubling the minutes should double the J/cm². Doubling the irradiance should do the same. If you change distance, the rate should follow the irradiance column, not the time column.
- FX300, 6 inches to 12 inches: the stated irradiance goes from 83.5 to 43.3, which is about 52 percent of the original. The J/cm² per minute drops by the same proportion.
- FX500, 6 inches to 12 inches: the stated irradiance goes from 94 to 73.8, which is about 79 percent of the original. The FX500 loses less per inch than the FX300 on these published figures.
- FX500, 2 inches to 20 inches: 220 falls to 58.6, which is about 27 percent. That is why a distance must travel with every number.
If your answer is a thousand times too big, you skipped the divide by 1000. If it is sixty times too small, you used minutes where the formula wants seconds.
Where a chart can mislead
- Values between rows are not measured. A figure for 8 inches is not on the chart, and guessing between 6 and 10 inches is only a guess.
- The figure is for one point. It describes a stated spot, not every part of the lit area.
- A chart is not a protocol. Reading a row does not tell you which row to use. Follow your manual.
- Close distances are for arithmetic. Rows at 1 to 3 inches are published specs, not working distances.
Common mistakes
- Using the 0.06 shortcut with irradiance in W/cm² instead of mW/cm².
- Reading the chart at a distance you do not actually sit at.
- Interpolating between rows and calling the guess a measurement.
- Using the example targets as if they were recommended doses.
- Using the FX300 table for an FX500, or the other way round.
- Rounding the rate too early and then multiplying by many minutes.
Before you use any light device: read the label, follow the device manual, and use eye protection as directed. This guide is general information about arithmetic and planning, not medical advice. For medical questions, speak to a qualified professional.
Related guides and tools
- The main dose calculation guide
- AWA FX300 and FX500 irradiance specs
- What irradiance means
- How long a session runs, by the manual
- Irradiance by distance chart
- Red light dose calculator
- Session time table
Device pages
Read the full page and label for each device before you use it: AWA FX300 panel, AWA FX500 panel. You can also browse the AWA panels, or the Learning Center for more guides.
Frequently asked questions
What is a red light therapy dose chart?
It is a lookup table that turns a stated irradiance and a session time into J/cm². Each cell comes from J/cm² = mW/cm² x seconds / 1000.
How do I get J/cm² per minute?
Multiply the irradiance in mW/cm² by 0.06. For example, 83.5 mW/cm² gives 5.01 J/cm² per minute.
Does the chart tell me how many minutes to use?
No. The minutes in the second set of tables belong to example targets. Your manual and product page set session length and distance.
Why do the minutes rise with distance?
Irradiance falls as you move back, so each minute delivers less energy per square centimeter. The same target therefore takes longer.
Can I use these numbers for other devices?
No. They apply only to the AWA FX300 and FX500 at the stated distances. Another device needs its own stated irradiance at its own distance.
Sources
- FDA: General Wellness: Policy for Low Risk Devices. January 2026 guidance from the FDA Center for Devices and Radiological Health on its compliance policy for low risk general wellness products. It is a policy document, not a statement about any one device.
- FDA: Premarket Notification 510(k). Explains that companies generally must submit a 510(k) before marketing certain medical devices in the U.S., showing substantial equivalence to a legally marketed device.
Regulatory note: select devices carry FDA 510(k) clearance for specific, limited uses; most are sold as general wellness products. Read each product page and label.
How we create this guide
AWA sells red light therapy devices. We write these guides to explain how devices work and how to choose and use one. This is general information, not medical advice. Read each product page and label. See our editorial standards.