Updated September 2026
Short answer: There is no single best distance for every red light therapy panel. Start with the instructions for your specific model and the area you want to illuminate. Moving farther away generally widens coverage and changes the irradiance arriving at your skin, but you cannot accurately convert minutes from one distance to another without measured output at both positions. For Hooga's HG300, we use 73 mW/cm² at six inches as the stated reference point. That is not the HG300's output at every distance, and it is not a universal treatment target (Hadis et al., light-measurement review).
Key takeaways
- Distance changes both coverage and exposure. A smaller illuminated area can be useful for a targeted setup; stepping back may cover more skin but changes the light arriving at each square centimeter (Hadis et al.).
- A six-inch specification applies at six inches. Do not insert it into a calculator for twelve or twenty-four inches without another measurement.
- Minutes alone do not describe a dose. At a known, steady irradiance, calculated surface exposure is mW/cm² × seconds ÷ 1,000 = J/cm². It does not equal absorbed energy inside muscle or skin.
- Follow your model's instructions for face and eye use. Distance is not a substitute for the eye-safety guide or the precautions in your manual.
Why does distance matter?
Irradiance is the rate of light energy reaching a surface per unit area, usually reported in milliwatts per square centimeter (mW/cm²). For a non-contact panel, the number that matters to a surface-dose calculation is the irradiance where your skin actually is, not the LED's electrical watt rating and not an output figure measured at the emitter. A radiometry review explains why beam geometry, measurement method and the location of the target must all be reported to make an exposure meaningful (Hadis et al.).
As you move away, LED beams spread and overlap differently across the treatment area. A larger panel is an array of sources, not a single point source. The inverse-square rule describes an ideal point source at suitable distances; it does not let us declare that doubling your distance from any particular panel cuts its measured irradiance to exactly one-quarter. Measure the panel's output at both distances, or use a trustworthy model-specific chart, rather than calculating a new product specification from that shortcut (Hadis et al.).
How should you choose a distance in practice?
| Your setup question | What to check | What not to assume |
|---|---|---|
| Do I want to illuminate a small area? | Your model's permitted positioning, the size of its light field at that distance, and comfort | Closer is always better or a higher irradiance guarantees a better result |
| Do I need wider coverage? | Whether the whole intended area is lit and whether irradiance is documented at the farther position | A larger light footprint delivers the same dose per cm² |
| Do I want to repeat a session consistently? | Use the same position, mode and timer, and record the approximate distance | “Ten minutes” is comparable across different panels |
| Am I using a mask, blanket or contact-style device? | Follow that device's instructions | A standing-panel distance chart applies to a wearable or contact device |
For a compact panel, repositioning it to cover adjacent areas may be more practical than moving far enough away to light everything at once. A larger panel can cover a broader zone with less repositioning, but its output still varies with location and distance. Compare current models in the Hooga panel buying guide, and follow the instructions for the model you own.
What changes at six, twelve and eighteen to twenty-four inches?
These distances are useful reference positions, not a universal protocol. At a close position such as six inches, you may illuminate a smaller area more intensely. At twelve inches, beam overlap and coverage may differ. At eighteen to twenty-four inches, a large panel can illuminate a broader area, but the resulting irradiance cannot be inferred from a six-inch specification alone. A compact panel may be a poor match for broad coverage at a farther position simply because its illuminated field is smaller. The actual trade-off depends on the model and where you stand relative to its LEDs (Hadis et al.).
This is also why a “minutes by distance” chart is unreliable without measured values. If you move from six to twelve inches, do not assume either that output halves or that a session must double. If you move to eighteen or twenty-four inches for full-body coverage, use your device's own positioning instructions and a measurement at that farther position before making a numerical dose comparison.
Does the right position differ for compact and full-body panels?
Yes, primarily because the panel's physical size and mounting change how much of you can be illuminated at once. The compact HG300 and ULTRA360 are easier to position for smaller areas; compare the area you want to expose with the panel's light field. A larger ULTRA4500 offers a different coverage setup, but it is not an invitation to transfer a compact panel's timer or six-inch irradiance to a full-body session.
The old article's “ideal” 4–8, 6–12 and 12–24-inch ranges for named models were broader than the evidence cited for them. Use the current instructions for your exact panel instead of treating those ranges as clinically validated distances. A full-body blanket is a separate close-to-body format and should not be positioned according to a standing-panel distance chart.
What does the HG300's 73 mW/cm² figure mean?
Hooga specifies the HG300 at 73 mW/cm² at six inches. For a constant output at that stated position, a five-minute arithmetic example is:
73 mW/cm² × 300 seconds ÷ 1,000 = 21.9 J/cm² estimated surface exposure.
Ten minutes in the same illustrative conditions would calculate to 43.8 J/cm². Neither number is a prescribed target, a claim about absorbed tissue dose, or an estimate for another model or distance. The calculation also assumes the stated irradiance is representative of the area and mode being considered; LED arrays can have non-uniform output (Hadis et al.). The complete dosage and frequency guide explains why equal J/cm² from different setups need not produce equal biological effects.
Can you make up for moving farther away by staying longer?
Sometimes the surface-exposure arithmetic can be matched if you know the measured irradiance at both distances. For the same calculated surface exposure, time at distance B = time at distance A × irradiance at A ÷ irradiance at B. That is a calculation, not a recommendation that biological effects are identical.
For example, if a device were independently measured at 60 mW/cm² in one position and 30 mW/cm² in another, five minutes in the first position and ten minutes in the second would both calculate to 18 J/cm² at the measured surface. Those are hypothetical numbers, not Hooga product specifications. Different coverage and irradiance patterns still matter, and a longer exposure is not automatically better. A review of photobiomodulation parameters discusses why wavelength, irradiance, time and biological response should not be reduced to one interchangeable number (Zein et al.).
A rule such as “10 minutes at six inches may take 20 minutes at 18–24 inches” is not a reliable panel-wide conversion. Without a measured 18- or 24-inch irradiance for the exact device, mode and position, it should not be used to set a session.
Do wavelength and skin goals change the distance?
Red and near-infrared (NIR) wavelengths have different optical interactions with tissue, but neither light category lets you ignore distance or measurement. A wavelength may penetrate differently after it reaches the surface; that is not the same as saying its output stays constant as you step away. For the red/NIR distinction, see our wavelength guide and red versus infrared comparison.
For a face session, do not infer an “ideal” close distance from a skin study performed with a different device. Check your exact model's distance and eye precautions. If the light feels uncomfortably warm, stop and consult the instructions; do not stare into the LEDs. Our eye-safety article covers the separate eye question. This guide is not an ophthalmology protocol.
How can you make your routine repeatable?
- Record the device and mode. Note whether you use red, NIR, both or another available setting.
- Use a repeatable position. A floor mark or fixed stand can help you return to approximately the same distance.
- Record the time and area. Keep the session within your model's instructions; do not copy another panel's minute count.
- Check direct exposure. Clothing can change how much light reaches skin. Our dosage and frequency guide explains the limits of estimating exposure through fabric.
- Avoid extrapolating from a single spec. A panel's six-inch figure cannot establish its output at twelve inches or its absorbed dose in deeper tissue.
Frequently asked questions
Is six inches the right distance for every Hooga panel?
No. Six inches is the stated measurement position for many panel specifications, not a universal session prescription. Product sizes, coverage, output and manual instructions differ. Check the product page and instructions for your exact model.
What if my device has no distance-by-distance irradiance chart?
Use the manufacturer's instructions and a repeatable position, but do not claim a precise J/cm² value at an unmeasured distance. If you need a defensible calculation, request measured output for that model and position.
Does moving twice as far away mean I should spend four times as long?
No such universal conversion follows for a multi-LED panel. Distance, beam overlap and measurement position matter, and matching calculated surface exposure does not guarantee matching outcomes (Hadis et al.).
References and disclosure
- Hadis MA et al. The dark art of light measurement: accurate radiometry for low-level light therapy. Lasers in Medical Science. 2016.
- Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy. Journal of Biomedical Optics. 2018.
- Photobiomodulation LED Devices for Home Use. 2025. Cited for the importance of output measurement and dose consistency, not a Hooga-specific test.
Written by: Hooga Editorial Team. Hooga has designed and sold photobiomodulation devices since 2019. This guide draws on published research, stated device specifications and practical product experience. It is general education, not a medical protocol or proof of a clinical result. Last updated: September 2026.