How do you mark a required field without cluttering the form?

The cleanest way to mark requirement is to mark whichever set is smaller: if most fields are required, label the few optional ones instead, and if only a few are required, mark those. Requirement is information about the exception, and you communicate an exception by flagging the minority, not by stamping a symbol on the majority. An asterisk on every field of a mostly-required form is visual noise that says almost nothing, because when everything is marked, the marking has stopped distinguishing anything. The trick is to signal the smaller group with one consistent, legible indicator and let the larger group be the unmarked default.

The principle underneath is that a marker only carries meaning by contrast with what is unmarked. If a ten-field form has nine required fields, putting an asterisk on nine of them forces the user to scan a thicket of symbols to find the single optional field by its absence, which is exactly backwards. Flip it: mark the one optional field with a quiet “(optional)” and the other nine read as required by default, no symbols needed. The same logic runs the other way on a form where only two of twelve fields are mandatory, where marking those two stands out cleanly while the ten optional fields stay clean. You are always pointing at the exception, because the exception is the information worth the ink.

Take a job application where every field except “LinkedIn URL” must be filled. The asterisk-everything habit produces a column of red stars marching down the page, drawing the eye to nothing in particular and making the form feel demanding before the user reads a word. Mark the minority instead and the page calms down immediately: ten clean labels plus one that reads “LinkedIn URL (optional),” and the user instantly understands the shape of the ask. The one piece of genuinely useful information, that they can skip LinkedIn, is now the only thing flagged, and the form stops shouting about obligations it could have left implicit.

There is one real limit: whichever indicator you choose has to be consistent and legible, and it cannot lean on color or a symbol alone. A required marker that is only a red asterisk fails users who cannot perceive the color or who use a screen reader, so the requirement must also be conveyed in text or through the field’s programmatic state, not just a visual glyph. And if a form is genuinely split close to half and half, the minority rule loses its edge, so in that case mark the required fields with a clear indicator and state the convention once at the top, since there is no smaller set to exploit. The goal is always the least marking that still communicates unambiguously.

There is also a subtler version of the same clutter, which is marking that is technically minimal but still ambiguous because the convention is never stated. An asterisk on three fields tells the user something is special about those three, but not what, so a one-line note such as “fields marked with an asterisk are required” turns a guess into a fact for almost no visual cost. The same applies when you mark the optional fields instead: the word “(optional)” is self-explanatory and needs no legend, which is a quiet point in its favor whenever the optional set is the smaller one. Choosing the indicator that explains itself, and stating the rule once when it does not, is how you keep the marking both sparse and unmistakable.

So before you reach for the reflex of asterisking every required field, count which set is smaller and mark that one. Use a single, readable indicator, give it a one-line legend so its meaning is never guessed, and make sure the requirement is available to assistive technology and not riding on color alone. Signal the exception, leave the rule implicit, and your form will tell users exactly what they need to know without a field of stars demanding attention it does not deserve.