LRV Paint Calculator: What It Is & How to Use It

The LRV paint calculator works out the Light Reflectance Value of a paint color from its RGB or hex code, and it also tells you how much light a painted surface will reflect in practical terms. You enter a color’s RGB values (or hex code), and the calculator returns the LRV on a 0–100 scale, plus an estimate of the perceived brightness in a room. This lets you compare paint colors objectively before you buy a sample.

Formula

The calculator uses the standard relative luminance formula from the sRGB color space, scaled to 0–100:

LRV ≈ 100 × (0.2126 × R_lin + 0.7152 × G_lin + 0.0722 × B_lin)

where R_lin, G_lin, B_lin are the linearized RGB values (each channel divided by 255, then transformed to remove gamma). For a quick approximation, many online calculators skip the gamma step and just use the raw 0–255 values directly, as we do here for simplicity. The exact formula used by paint manufacturers is more complex and involves the CIE color space, but the linear RGB version gives a close enough number for comparing colors.

• R, G, B – the red, green, and blue components of the color, each from 0 to 255.
• LRV – the resulting Light Reflectance Value, expressed as a percentage from 0 (pure black) to 100 (pure white).

Worked Example

Using the defaults from the calculator (R=200, G=150, B=100), let’s find the LRV:

1. Divide each channel by 255: R = 200/255 = 0.7843, G = 150/255 = 0.5882, B = 100/255 = 0.3922.
2. Apply the coefficients: 0.2126 × 0.7843 = 0.1667, 0.7152 × 0.5882 = 0.4207, 0.0722 × 0.3922 = 0.0283.
3. Sum them: 0.1667 + 0.4207 + 0.0283 = 0.6157.
4. Multiply by 100: LRV = 61.6%.

The calculator shows 61.6%, which matches. This is a medium-light warm beige—it reflects a little over half the light that hits it.

What LRV Actually Tells You

LRV is a standard metric used by paint manufacturers to describe how much light a paint color reflects. It’s measured on a scale of 0 to 100, where 0 is absolute black (absorbs all light) and 100 is pure white (reflects all light). Most paint colors fall between 3 and 93.

In practical terms, LRV affects:

• Room brightness: Higher LRV colors make a room feel brighter and more open, especially in spaces with little natural light.
• Contrast and depth: Lower LRV colors create drama and can make a large room feel cozier, but they also make walls feel closer.
• Energy efficiency: In hot climates, high-LRV exterior paint reflects more solar heat, which can reduce cooling costs. In cold climates, low-LRV paint can help absorb heat.
• Lighting design: The same lamp will appear dimmer in a room painted with low-LRV walls because more light is absorbed.

Keep in mind that LRV is a property of the paint itself, not of the surface it’s applied to. A rough or textured wall will scatter light differently than a smooth one, but the LRV number remains the same.

How to Choose an LRV for Your Room

There’s no “best� LRV—it depends on the room’s purpose, size, and natural light. Here are general guidelines:

• High LRV (70–100): Best for small rooms, hallways, basements, or any space lacking windows. White, off-white, and pastel colors fall here.
• Medium LRV (40–70): Good for living rooms, bedrooms, and dining areas. These colors feel balanced and work well with most lighting.
• Low LRV (10–40): Ideal for accent walls, home theaters, or rooms where you want a moody, intimate feel. Dark blues, greens, and charcoals are in this range.
• Very low LRV (below 10): Used sparingly for dramatic accent features or exterior trim. These colors absorb most light.

Also consider the undertone of the color. Two colors with the same LRV can look very different—one might have a blue undertone and another a yellow undertone, which affects how they appear under warm vs. cool lighting.

Common Mistakes When Using LRV

One of the biggest mistakes is assuming LRV is the same as “brightness� as your eye perceives it. LRV is a physical measurement of total reflected light, but our eyes are more sensitive to green and yellow wavelengths. That’s why the calculator also shows a “perceived brightness� using the Rec. 601 luma coefficients—it gives a more human-centric number.

Another common error is mixing up the scale. Some older paint chips label LRV as a number from 0 to 100, but others use a 0–1 scale. Always check which scale you’re using. Our calculator outputs a percentage, so 0.5 on a 0–1 scale equals 50%.

Also, don’t rely solely on LRV to predict how a color will look. The same LRV can appear quite different depending on the paint’s sheen (flat, eggshell, satin, gloss). Glossier paints reflect more light directly, making the color look lighter and more saturated, while flat paints scatter light and can make a color look darker and more muted.

Limits of the Formula

The formula used here is a simplified version of the true LRV calculation. Paint manufacturers use a spectrophotometer to measure the actual reflectance of a dried paint film across the visible spectrum, then weight it according to the CIE standard observer. The result is a precise LRV that can differ from our RGB-based estimate by a few points.

Why? Because RGB values are device-dependent—the same hex code can appear slightly different on different monitors. Also, the conversion from RGB to LRV is not a simple linear formula; it involves a gamma correction that our simplified version skips. For most purposes, the difference is small (usually within ±3 points), but if you need the exact LRV for a specific paint brand, check the manufacturer’s technical data sheet.

Another limitation: LRV does not account for the color’s hue. A bright yellow and a bright blue might have similar LRV, but they absorb and reflect different wavelengths, which affects how they feel in a room. Use LRV as one tool among many—not the sole deciding factor.

Alternatives to LRV

If you don’t have an RGB value, you can still estimate a paint’s lightness by eye. Many paint brands publish LRV on their color cards or websites—just search the color name. You can also use a colorimeter or a smartphone app that measures reflectance, though these are less accurate than a spectrophotometer.

Another related metric is reflectance, sometimes called “total solar reflectance� (TSR) for exterior paints. TSR measures how much solar energy (including infrared) is reflected, while LRV only covers visible light. For exterior walls in hot climates, TSR is more relevant for energy savings.

If you’re designing for accessibility, LRV is also used to ensure sufficient contrast between adjacent surfaces (e.g., walls and trim) for people with low vision. A difference of at least 30 points in LRV is often recommended for good contrast.

Frequently Asked Questions

What is a good LRV for a bedroom?

For a bedroom, most people prefer a calm, relaxing atmosphere, so an LRV between 40 and 70 works well. If the room gets plenty of natural light, you can go lower (30–40) for a cozy feel. If it’s a small or dark room, choose a higher LRV (70+) to make it feel airy.

Can I use LRV to compare colors from different brands?

Yes, LRV is a standard metric, so you can compare a color from Brand A with one from Brand B. However, because each brand measures LRV slightly differently, the numbers may not be perfectly comparable. For a fair comparison, look for colors with similar LRV and then view actual paint swatches under your lighting.

Does LRV change with paint sheen?

The LRV number itself is measured on a perfectly flat, matte surface. Glossier paints will reflect more light directly, making the color appear lighter and more saturated, but the official LRV value remains the same. In practice, a satin or gloss finish can make a color look 5–10 points lighter than its flat counterpart.

What is the LRV of pure white?

Pure white (RGB 255, 255, 255) has an LRV of 100%—it reflects all visible light. In reality, most “white� paints have an LRV between 80 and 93 because they contain pigments that absorb a tiny amount of light. The whitest paints you can buy typically have an LRV around 93.

How do I find the RGB value of a paint color?

Most paint brands provide RGB or hex codes for their colors on their websites. You can also use a color picker tool on a digital image of a paint chip, or a smartphone app that identifies colors from photos. Keep in mind that the RGB value you get from a photo may not be perfectly accurate due to lighting.

Is a higher LRV always better?

Not necessarily. High LRV makes a space feel bright and open, but it can also feel sterile or glaring if used everywhere. Low LRV adds depth and coziness, but too much can make a room feel like a cave. The best LRV depends on the room’s function, size, and your personal preference.

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in r | Red (0-255) | - | 200 | 0
in g | Green (0-255) | - | 150 | 0
in b | Blue (0-255) | - | 100 | 0
out lrv | Light Reflectance Value | % | (0.2126 * r / 255 + 0.7152 * g / 255 + 0.0722 * b / 255) * 100 | 1
out brightness | Perceived brightness | % | (0.299 * r + 0.587 * g + 0.114 * b) / 255 * 100 | 1