The short answer: a coastal palette holds together at roughly 60% white, 30% sand or driftwood, and 10% blue or green, with a single dark used sparingly. On Benjamin Moore's own color pages, its whitest coastal option, Simply White, carries an LRV of 89.52; its coastal navy, Hale Navy, sits at 8.36, a gap of more than 80 points that is most of why the contrast reads as deliberate rather than random. Bathrooms and other humid rooms get a matte finish under Benjamin Moore's own guidance, not the higher-shine sheen most people reach for.
Most coastal color guides stop at naming the swatches: a white, a sand, a blue-green, maybe a navy. That's a starting point, not a palette. What decides whether the result looks like a beach house or a room that's merely pale is the proportion of each color, how much light each one reflects, and what the room's own light does to it over the course of a day. Below are those three things, with the color numbers read directly off the manufacturer's own pages rather than off memory or a swatch app. If the palette is going into a living room, our living room paint colors guide adds the step that comes first: which way the window faces.
The Proportion: 60, 30, 10
A widely used rule of thumb for splitting color in a room is 60-30-10: 60% of the visible surface in a dominant color, 30% in a secondary, 10% in an accent. In a coastal room, that maps onto the palette almost exactly:
- 60%, the white. Walls, ceiling, trim, and usually the biggest upholstered piece. This is the most consequential decision in the palette and the one people spend the least time on.
- 30%, the sand or driftwood. Floors, a rug, wood furniture, linen that isn't white. This layer is mostly not paint at all; it's what keeps the room from reading as a white box.
- 10%, the blue or green. Cushions, a throw, one piece of art, or a single wall in a bedroom or bathroom. Ten percent is less than most people use; put the blue on the sofa, the rug and the walls at once and the room has moved into nautical or Hamptons territory, which run on different math.
An optional fourth layer, at 1–3%, is a dark: a picture frame, a lamp base, a door. It shows up at the end of the color table below.
Erstellt mit AIWhat LRV Means, and Why the Gap Matters More Than the Colors
Every paint color has a Light Reflectance Value, a number from 0 to 100 for the percentage of light it bounces back, and paint makers typically publish it on the color's own page. A coastal room is, before anything else, a high-LRV room: walls in the 80s and 90s, floors and fabrics in the 60s, and the style's "airy" feel comes directly from those surfaces throwing most of the daylight back into the room instead of absorbing it.
The number that matters more than any single color's LRV is the gap between the white and the accent. Simply White at 89.52 next to Beach Glass at 49.7 is a gap of about 40 points, which reads as a bright field with a color sitting clearly inside it. Our rule of thumb: two colors within ten points of each other tend to read as a mismatch rather than a choice, even when both are attractive on their own.
Six Colors, With Numbers Read Off the Source
These LRVs come straight from Benjamin Moore's own color pages, one color at a time, rather than a swatch chart or a decorating blog's summary of them. Sherwin-Williams, Behr and Farrow & Ball each run their own coastal-toned lines with their own numbers; Benjamin Moore's set below covers the same 60-30-10 roles on its own.
| Color (name and code) | LRV | Where it works |
|---|---|---|
| Simply White (OC-117) | 89.52 | Walls, trim and ceilings: the 60% layer, best in a room with decent daylight |
| Pale Oak (OC-20) | 68.64 | A hallway, a wainscoted wall, or anywhere that wants warmth without going full white |
| Beach Glass (1564) | 49.7 | One wall, a vanity, or cabinetry: the 10% accent |
| Wythe Blue (HC-143) | 48.11 | A front door or a single accent wall, grayer and a touch cooler than Beach Glass |
| Carolina Gull (2138-40) | 27.41 | An island, built-in cabinetry or a mudroom: a deeper mid-tone, not a whole living room |
| Hale Navy (HC-154) | 8.36 | A door, a lamp base or a frame, the 1–3% dark, kept off full walls |
Notice where the accent colors sit: Beach Glass and Wythe Blue, both usable on a full wall, are in the high 40s, a comfortable 20 to 40 points below the whites above them. Carolina Gull, at 27.41, reads as a deliberate mid-tone rather than a pale color and belongs on a smaller surface. Hale Navy, at 8.36, absorbs the great majority of light that reaches it; a little goes the entire way.
North Light and South Light Change the Same Blue
Erstellt mit AIThe same six colors read differently depending on which way the windows face, and this part is a working rule of thumb rather than a manufacturer figure: no paint company publishes a number for "how a color behaves in a north room," because it depends on the specific window, climate and time of year.
South- and west-facing rooms get direct, warm light for much of the day. Pale colors read brighter, and a cooler white like Simply White holds its own without drifting toward beige. These rooms can carry a bluer, grayer accent like Wythe Blue without the room feeling cold.
North-facing rooms get indirect, cooler, blue-tinged light all day. Colors read flatter, and a white with much gray in it can go dead by mid-afternoon. A room like this tends to want a warmer white and a greener accent, such as Beach Glass, rather than a pure blue. A pale, gray-blue in a north room is the classic version of the coastal mistake, ending up looking cold instead of calm.
Our rule of thumb for sampling: paint a large swatch, at least two feet square, on the actual wall, and look at it in the morning, in the afternoon and after dark under the bulbs that will actually be in the room. A color that's right at noon and wrong at eight in the evening is wrong.
Sheen for Bathrooms and Other Humid Rooms
Coastal palettes lean heavily on bathrooms and mudrooms, and the finish matters there as much as the color. Benjamin Moore's own paint-finish guidance points to a matte finish for bathrooms and other rooms exposed to more moisture, specifically its Aura Bath & Spa line, citing durability, color retention and mildew resistance; it lists a pearl finish as the mildew-resistant alternative for high-humidity spaces that need to stand up to more washing. That runs against the common assumption that a wet room automatically wants a glossier paint: check the sheen's own listing before assuming semi-gloss is the safe default, since finishes and their moisture ratings vary by product line. The coastal bathroom is where this choice actually gets made, alongside the fixtures and tile.
How Coastal Differs From Mediterranean
Both styles use blue and white, which is where the confusion starts. The difference is in the proportion and in the LRV range. A coastal palette keeps almost everything pale: the 60% white sits in the high 80s and 90s, and even the sand layer stays light. A Mediterranean coastal palette runs warmer and darker throughout: terracotta, ochre and deep blue sit well below coastal's whites on the reflectance scale, and the accent color is often a much larger share of the room, not held to 10%. A coastal room that borrows Mediterranean's warm plaster tones for its "sand" layer usually reads as neither style, because the two are built on different light budgets.
The same proportional logic threads through the rest of the coastal style: the living room keeps the blue to the 10% layer, the dining room is where a single dark gets used on the chairs, and general coastal decor choices (driftwood, rope, linen) fill the 30% layer that isn't paint at all.
