Navy looks like it should go with everything and does not. The cardigan is where most navy outfits come apart.
Navy is treated as a neutral and behaves like a color. It has a temperature, it has a depth, and it disagrees with other colors in ways black simply does not.
The particular problem with a cardigan is proximity. It sits directly against the dress along the whole front opening, so any mismatch is visible in a continuous line rather than in separate blocks. This is why a navy outfit can look slightly wrong without anybody being able to say why.
The Five That Work
Cream and Ivory
The most reliable answer and the one to reach for if you want to stop thinking about it. Cream is warmer than white and softens navy's coolness without competing. It reads as considered in a way that pure white does not, because white against navy is a strong contrast that can look like a uniform.
Camel and Tan
The most elegant of the group. Camel is navy's natural partner: warm against cool, mid against deep, and neither one dominates. A camel cardigan over a navy dress is a combination that has been correct for sixty years and shows no sign of stopping.
Gray
The quietest option and the most modern. A mid gray sits between navy and cream in depth, which keeps the outfit tonal rather than contrasting. Choose a gray with a cool cast rather than a warm one, which can read as slightly muddy against navy.
Burgundy and Wine
The one that looks like it should not work and does. Both are deep, so nothing competes, and burgundy's warmth lifts navy out of looking severe. This is the combination for fall and winter and it is considerably more interesting than the neutrals.
Navy Itself
Tonal dressing, and the most sophisticated of the five when the two navies genuinely match. The risk is that they do not. Two navies that are close but not identical look like an accident, whereas two that are clearly different in depth look deliberate. Either match exactly or do not try.
The One That Rarely Does
Black. It is the instinct and it is almost always the wrong answer. Black against navy is close enough to read as an attempted match and far enough apart to fail, and in daylight the difference is obvious. In low evening light it is fine, which is why people get away with it and then look at the photographs.
If you want dark, go darker in another direction: charcoal, forest or that burgundy.
Black against navy is close enough to look like a mistake and far enough apart to be one.
Getting the Proportions Right
Color is half of it. The length of the cardigan is the other half, and it matters more than most people allow.
A cropped cardigan ending at the waist keeps the waist of the dress visible, which is what makes most dress shapes work. It is the safest length over a fit and flare or an A-line.
A hip-length cardigan over a midi cuts the body into three sections and is the least helpful length there is. If you own one and love it, wear it open and let the vertical line of the opening do the work instead.
A long cardigan reaching the knee or below works precisely because it creates one unbroken vertical line down the front. Worn open over a navy midi it is elegant and very easy.
The rule underneath all three: the cardigan should either stop at the waist or be long enough that the eye reads it as a column. Anything in between divides you at the hip.
Fastened or Open
Open is safer and more flattering to the outfit, because the dress remains visible and the line stays vertical.
Fastened turns the pairing into something closer to a twinset, which is a specific and slightly formal look. If you fasten it, fasten it all the way or from the waist down, not one button in the middle, which pulls the fabric into a diagonal.
A cardigan worn open wants something at the neck of the dress to look at: a neckline with a shape to it, or a single pendant. An open cardigan over a plain round neck can read as unfinished.
Fabric and Weight
Match the weight of the knit to the weight of the dress. A chunky knit over a fine crepe dress looks like two unrelated garments. A fine knit over a heavy winter dress disappears.
Texture is the easiest way to make a neutral cardigan interesting. A cable, a rib or an open knit in cream does considerably more than a flat cream knit, and it costs nothing extra in styling effort.
For evening, a fine knit with some sheen or a metallic thread lifts a navy dress without changing its register. It is a more useful thing to own than most people expect.
Shoes and the Rest
Let the shoe agree with the cardigan rather than the dress. Cream cardigan, nude or tan shoe. Camel cardigan, tan or brown shoe. Burgundy cardigan, black or burgundy shoe. That single habit pulls the whole outfit together with no further thought.
Keep the metal consistent. Gold with camel, cream and burgundy. Silver with gray and navy. It is a small thing and it is visible.
Cardigans That Sit Well With Navy
Common Questions
What Does a Cardigan Look Like?
A cardigan is a knitted garment that opens down the front, fastened with buttons, a zipper or left open, as distinct from a pullover that goes over the head. It comes cropped at the waist, at hip length, or long to the knee and below, and in weights from a fine gauge knit to a chunky cable. The open front is the defining feature.
What Color Cardigan to Wear With Navy Dress?
Cream, camel, gray, burgundy or a navy that matches exactly. Cream is the most reliable and camel the most elegant, because warm against cool is what stops navy looking severe. Burgundy works for fall and winter and is more interesting than the neutrals. Avoid black, which is close enough to navy to look like a failed match in daylight.
What to Wear Under V Neck Cardigan?
A neckline with some shape to it, so the V has something to frame. A round neck or a boat neck in a plain color works, as does a collar left showing at the top. A camisole alone under a deep V reads as underwear rather than an outfit. If the cardigan is being worn open over a dress, the dress neckline does this job already.
The Short Version
Cream, camel, gray or burgundy against navy, or a navy that matches exactly. Not black. Keep the cardigan cropped at the waist or long enough to read as a column, wear it open, match the knit weight to the dress, and let the shoe agree with the cardigan rather than the dress.