Proximity in form layout

Forms are the canonical proximity case. A form with poor proximity produces ambiguous label-input pairings, orphaned help text, sections that don't read as sections, and a general feeling that the user must "decode" the layout before they can fill it in. A form with good proximity reads as a structured set of pairs and groups; the user fills it in without thought.

The form proximity ladder

Use four nested levels of spacing — each level visibly tighter than the level above it:

Level 1: gap-1   (4px)    inside a label-input pair
Level 2: gap-3   (12px)   between fields in a group
Level 3: gap-6   (24px)   between groups within a section
Level 4: gap-10  (40px)   between sections

Each level should be at least 2× the level inside it. Don't use gap-2 and gap-3 for different roles — they look identical.

The label-input pair

The single most important proximity decision in a form: the label belongs with the input it labels. Every other proximity issue cascades from this.

Top-aligned labels (default for vertical forms)

<style>
  .form { display: grid; gap: 1.5rem; max-width: 400px; }     /* Level 3 between groups */
  .field { display: grid; gap: 0.25rem; }                      /* Level 1 inside pair */
  .field-help { font-size: 0.8rem; color: hsl(0 0% 45%); }     /* tone reduction for tertiary */
</style>

<form class="form">
  <div class="field">
    <label for="email">Email address</label>
    <input id="email" type="email" required />
    <p class="field-help">We'll send a verification link.</p>
  </div>
  <div class="field">
    <label for="password">Password</label>
    <input id="password" type="password" required />
  </div>
  <button type="submit">Sign up</button>
</form>

The label, input, and help text are bound by tight (4px) spacing. The fields are separated by loose (24px) spacing. Pairing reads instantly.

Inline labels (left-aligned, common in admin and settings)

<style>
  .form-grid {
    display: grid;
    grid-template-columns: 10rem 1fr;          /* fixed label column */
    gap: 0.75rem 1rem;                          /* row gap, column gap */
    max-width: 600px;
  }
  .form-grid label { padding-top: 0.5rem; text-align: right; }
  .form-grid .field-help { grid-column: 2; font-size: 0.8rem; color: hsl(0 0% 45%); }
</style>

<form class="form-grid">
  <label for="display-name">Display name</label>
  <input id="display-name" />

  <label for="email">Email</label>
  <input id="email" type="email" />
  <p class="field-help">Used for login and notifications.</p>

  <label for="role">Role</label>
  <select id="role">…</select>
</form>

Note how the help text appears in the right column under its input — proximity binds it to the field, not to the label across the row.

Section grouping

When a form spans more than ~5 fields, group them. Sections get distinctly larger spacing than between fields, plus a heading.

<form style="display: grid; gap: 2.5rem; max-width: 480px;">
  <section style="display: grid; gap: 1rem;">
    <h2 style="margin-bottom: 0.25rem;">Profile</h2>
    <div class="field"><label>Display name</label><input /></div>
    <div class="field"><label>Bio</label><textarea></textarea></div>
  </section>

  <section style="display: grid; gap: 1rem;">
    <h2 style="margin-bottom: 0.25rem;">Notifications</h2>
    <div class="field"><label>Email frequency</label><select>…</select></div>
    <div class="field"><label>Quiet hours</label><input /></div>
  </section>

  <section style="display: grid; gap: 1rem;">
    <h2 style="margin-bottom: 0.25rem;">Security</h2>
    <div class="field"><label>Two-factor</label><div>…toggle…</div></div>
  </section>
</form>

Three ranks of spacing (1rem within a section, 2.5rem between sections, plus the tight 0.25rem inside each field). The heading is slightly closer to its first field (0.25rem) than to neighbors (1rem) so it groups with what it labels.

Required indicators

A common proximity question: where does the asterisk go? Right next to the label text, with no space:

<label>Email <span class="required" aria-hidden>*</span></label>

Not:

<label>Email</label> <span class="required">*</span>     <!-- detached, looks like body content -->

The asterisk is part of the label, not a separate element. Proximity confirms.

Inline error messages

Errors should appear below the field they reference, with tight spacing:

<div class="field" data-state="error">
  <label for="email">Email</label>
  <input id="email" type="email" aria-invalid="true" aria-describedby="email-error" />
  <p id="email-error" class="field-error">Please enter a valid email.</p>
</div>

<style>
  .field-error {
    font-size: 0.8rem;
    color: hsl(0 75% 35%);
    margin-top: 0.25rem;     /* same as label-input gap */
  }
</style>

The error sits inside the field group's tight cluster, so the user reads it as part of the field, not as page-level content.

Multi-column forms

Sometimes density requires placing fields side-by-side (first name / last name; city / state / zip). Proximity-friendly multi-column layout:

<style>
  .field { display: grid; gap: 0.25rem; }
  .row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }   /* same as field gap */
</style>

<form style="display: grid; gap: 1rem; max-width: 480px;">
  <div class="row">
    <div class="field"><label>First name</label><input /></div>
    <div class="field"><label>Last name</label><input /></div>
  </div>
  <div class="row" style="grid-template-columns: 1fr auto auto;">
    <div class="field"><label>City</label><input /></div>
    <div class="field"><label>State</label><select>…</select></div>
    <div class="field"><label>ZIP</label><input style="width: 6rem;" /></div>
  </div>
</form>

The horizontal gap (gap: 1rem) within a row matches the vertical gap between rows. Each field is a tight pair internally. The user reads "first name + last name as a paired row," distinct from the row above.

Anti-patterns

Equal vertical spacing. Label, input, label, input all separated by the same gap. Pairing is ambiguous; users read carefully.
Help text outside the pair. Help text in a sidebar or above the section heading. The user has to look elsewhere to understand the field. Place help text under its input, tightly bound.
Section heading equally spaced above and below. The heading should be tighter to its own section than to the previous section.
Border-as-section. Wrapping each section in a card with a 1px border because the spacing isn't doing the work. First fix the spacing; the borders may not be needed.
Mobile mush. A form that's nicely grouped on desktop collapses on mobile because the responsive layout reduced all gaps to one value. Maintain the proportional ladder at every breakpoint.

Heuristics

Cover and pair. Cover all but two adjacent elements. Can you tell if they're a pair or two separate items? If not, the gap is wrong.
The 'gap audit'. List every distinct gap value used in the form. There should be 3–5, each visibly different. Many distinct gaps near each other (8px, 10px, 12px, 14px) signal accidental spacing.
Mobile line-up test. At 320px viewport, the form should still read as discrete groups. If it becomes a single column of evenly-spaced rows, proximity has collapsed.

Related sub-skills

proximity (parent) — the principle in full.
proximity-data-tables — applying the same idea to tabular data.
hierarchy-spatial — spatial hierarchy between groups; complementary to proximity within groups.