# Checkbox

> A control for independent on/off choices — any number of which can be selected at once, including none.

- Category: UI Components
- Canonical: https://www.themasterly.com/glossary/checkbox-ui

A checkbox is a control for independent on/off choices. Any number can be selected, including none, and that independence is the entire basis for choosing it over a [radio button](https://www.themasterly.com/glossary/radio-button).

The test is two questions. Could somebody reasonably want more than one of these? Could they reasonably want none? A yes to either makes it a checkbox.

## Checkbox against radio

| | Checkbox | [Radio](https://www.themasterly.com/glossary/radio-button) |
|---|---|---|
| Choices | Any number, including none | Exactly one |
| Options must be | Independent | Mutually exclusive and exhaustive |
| Can be cleared | Yes | No, once set |
| Single instance | A binary opt-in | Never — a lone radio cannot be unset |

The last row is the one products get wrong. A single radio button is a trap: once chosen it cannot be unchosen, which leaves somebody stuck with an answer they cannot retract.

## The indeterminate state

The third state, usually a dash, means "some of the things below this are selected". It belongs on select-all controls and on parent nodes in a tree.

Two rules keep it sane. It is a **display state only** — a user clicking an indeterminate checkbox must land on checked or unchecked, never back into the dash. And the parent must reflect its children honestly: if six of forty rows are selected, the header checkbox shows indeterminate, not unchecked.

This matters in B2B specifically, because the select-all checkbox on a paginated table has to answer a question the design usually ducks: does "all" mean this page or the whole set? Say which, and offer both.

## Writing the label

**State what checking it does, positively.** "Send me product updates" is checkable. "Do not send me product updates" makes an unchecked box mean consent, which is a double negative and, in consent flows, a dark pattern.

**Make the whole label a target.** A four-millimetre box is a small target; the label doubles or triples it for free, and it is the default behaviour of a properly associated label.

**One idea per box.** A label joining two things with "and" cannot be answered honestly by somebody who wants one of them.

## Defaults carry more weight than anything else

A checked box is accepted far more often than an unchecked one is checked. That makes the default a decision about the outcome, not a convenience.

Where the default is genuinely helpful, set it. Where it produces consent, a purchase, or data sharing, leaving it unchecked is the honest choice, and in several jurisdictions the legal one. A pre-ticked box for anything a person would decline if asked directly is the clearest single marker of a design optimising against its users.

## In practice

A settings page has a notifications section with a single checkbox: "Email notifications". It is checked by default, and the support queue carries a steady trickle of people asking why they get so much email.

Watching it explains the problem. The one box controls seven different kinds of message, from a weekly digest to a security alert. People who want one and not the others have two options: everything or nothing, and most choose nothing, which means the security alert stops too.

Replacing it with seven checkboxes and a select-all that shows indeterminate when some are on ends that category of ticket. The security alert also moves out of the group entirely, because it is not something to be opted out of casually.

## Where teams get it wrong

- **A checkbox where the options are exclusive.** Two answers that cannot both be true.
- **A single radio button.** Choosable once and never retractable.
- **Negative labels.** Unchecked meaning yes.
- **Pre-ticked consent.** Legal exposure and a plain signal of intent.
- **One box for several things.** Unanswerable honestly.
- **A styled div.** No keyboard, no announcement, no label association.

## Related terms

- [Radio Button](https://www.themasterly.com/glossary/radio-button)
- [Form Design](https://www.themasterly.com/glossary/form-design)
- [Input Field](https://www.themasterly.com/glossary/input-field)
- [UI Design](https://www.themasterly.com/glossary/ui-design)

## FAQ

**When should you use a checkbox instead of a radio button?**

When the options are independent and any number can be chosen, including none. Radio buttons are for one choice from a set, and the set must be exhaustive. If a person could reasonably want two of the options, or none of them, it is a checkbox.

**What is an indeterminate checkbox?**

A third visual state, usually a dash rather than a tick, meaning some of the things under this checkbox are selected and some are not. It appears on select-all controls and in tree structures, and it is a display state only: clicking it must resolve to checked or unchecked.

**Should a single checkbox be used for yes/no?**

Only when unchecked genuinely means no and the default is safe. For consequential or legally meaningful choices, two radio buttons force a deliberate answer, where an unchecked box cannot be distinguished from a box nobody read.

**How should checkbox labels be written?**

As a positive statement of what checking it does, and the whole label should be clickable. Avoid negatives: "Do not send me updates" checked is a double negative somebody has to decode, and it is the construction most often used to mislead.

**What accessibility does a checkbox need?**

A real input rather than a styled div, a label properly associated with it so the text is clickable and announced, a visible focus indicator, and space to toggle with the keyboard. Custom checkboxes built from icons routinely lose all four.

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