How to Choose Paint Colors: Undertones Explained

Why your "simple gray" turned out purple, and how to see the hidden color inside every neutral before it goes on the wall.

Row of neutral paint swatches showing warm, cool and green undertones side by side

Choosing a neutral paint should be easy. It is beige, or gray, or white. Then it goes on the wall and suddenly the gray looks lilac, the beige looks pink and the white looks faintly green. The culprit is the undertone: the subtle color hiding inside every neutral. Learn to see it and you will stop wasting cans of paint.

What an undertone is

Almost no paint is a pure color. A gray is made from black and white plus a little of something else, often blue, green, red or yellow, that gives it character. On a small card, under store lighting and surrounded by other colors, that hidden tint is hard to see. On four walls of a room, it multiplies and becomes obvious.

Broadly, undertones fall into two families:

  • Warm undertones: yellow, red, orange, pink. They make colors feel cozy and soft.
  • Cool undertones: blue, green, violet. They make colors feel fresh and crisp, sometimes cold.

How to spot the undertone

Compare, do not look alone

An undertone is almost invisible on its own. Place the swatch next to a few similar colors and it appears immediately. Next to a pure white sheet of printer paper, a “white” paint will show whether it leans yellow, pink, gray or blue. Next to other grays, one will look greener, another bluer.

Look at the darkest color on the strip

Paint cards often show several shades of the same color from light to dark. The darkest shade reveals the undertone most clearly. If the bottom of a strip of grays ends in a slate blue, the pale gray at the top will lean blue on your wall.

Check it against fixed things

Hold the swatch against your floor, kitchen units, sofa and stone. Undertones that clash look dirty or “off”. A cool blue-gray beside a warm honey oak floor can make both look wrong, while a warm greige ties them together.

Matching undertones to the room

  • North-facing rooms have cool light, so warm undertones usually feel better. Cool grays can look dull and cold.
  • South-facing rooms have warm light and can take cooler undertones, which balance the warmth.
  • Rooms with warm wood floors often look best with warm or neutral undertones.
  • Rooms with cool stone or gray tiles suit cooler or neutral undertones.

For more on how direction changes color, read reading light before you choose materials.

Common surprises, explained

  • “My gray looks purple.” It has a red or violet undertone, made stronger by cool light.
  • “My white looks yellow.” It has a warm undertone, made stronger by warm light or yellow bulbs.
  • “My beige looks pink.” It has a red undertone. A beige with a yellow or green undertone looks more natural in many rooms.
  • “My greige looks green.” Greige often carries a green undertone, which reads stronger beside green plants or in north light.

Finish matters too

The same color looks different depending on the finish. Matte paint absorbs light and hides wall imperfections, and colors look softer and slightly darker. Eggshell and satin reflect a little light, wipe clean more easily and suit kitchens, bathrooms, hallways and woodwork. Gloss is highly reflective and best kept for small details.

A simple routine for choosing

  1. Choose three to five candidates that you like.
  2. Compare them side by side against white paper to see their undertones.
  3. Remove any that clash with your floor and large furniture.
  4. Paint large samples and look at them at different times of day.
  5. Live with the remaining two for a few days before deciding.

It feels slow, but it is much faster than repainting a room.