check box (checkbox)

Short answer

Use checkbox (one word) to name the UI control; use check the box (two words) when check is a verb and box is a noun (an instruction). Avoid check-box (hyphen) unless a style guide forces it.

checkbox - the control itself (preferred in UI copy and documentation).
check the box - an action or instruction.
check-box - rarely needed; usually avoid.

Core explanation: name vs action

If you mean the control, use the closed compound checkbox: "Select the checkbox." If you mean the action, write the verb phrase: "Check the box if you agree."

Control name → checkbox.
Action/instruction → check the box.
They differ because one reads as a noun and the other as a verb phrase.

Spacing and hyphenation

Modern UI and technical writing almost always use checkbox for the element name. Leave the words separate when the verb check applies to the noun box. Hyphens are uncommon and add friction unless your house style requires them for modifiers.

Use "checkbox" for element names and labels in documentation.
Use "check the box" for instructions and natural prose.
Avoid "check-box" unless a style guide explicitly demands hyphens.

Grammar: plurality, verbs, and capitalization

The plural is checkboxes. Use verbs that match the platform: click, tap, select, check, or tick (British). UI labels should be concise and often omit the word checkbox altogether-reserve it for documentation or settings.

Plural: one checkbox, two checkboxes.
Verbs: "click the checkbox", "check the box", "tick the box" (regional).
Capitalize according to your UI style (Title Case or sentence case) and be consistent.

Real usage and tone: UI copy vs. instructions vs. casual speech

In UI copy and docs, treat checkbox as a noun. In conversational instructions or spoken directions, check the box sounds natural and clear. Pick one term for your product and apply it consistently.

UI/Design: use concise labels next to the control; reference "checkbox" in docs only when needed.
Instructional prose: "To sign up, check the box for newsletters."
Casual: "I couldn't find the checkbox" or "Just check the box" depending on tone.

Examples: before/after pairs for work, school, and casual contexts

Below are common mistakes and recommended fixes. Use the right-hand forms for UI copy or formal documents.

Work - Wrong: Click the check box to accept the terms.
Work - Right: Click the checkbox to accept the terms.
Work - Wrong: Please tick the check box next to your name.
Work - Right: Please tick the checkbox next to your name.
Work - Wrong: Enable the check-box filter to narrow results.
Work - Right: Enable the checkbox filter to narrow results.
School - Wrong: On the quiz, mark the check box for true statements.
School - Right: On the quiz, mark the checkbox for true statements.
School - Wrong: There is a check box beside each assignment title.
School - Right: There is a checkbox beside each assignment title.
School - Wrong: Students must fill the check box for attendance.
School - Right: Students must fill the checkbox for attendance.
Casual - Wrong: I couldn't find the check box to unsubscribe.
Casual - Right: I couldn't find the checkbox to unsubscribe.
Casual - Wrong: Just click the check box and you're done.
Casual - Right: Just click the checkbox and you're done.
Casual - Wrong: Is it a check box or radio button?
Casual - Right: Is it a checkbox or a radio button?

Try your own sentence

Context decides the form. Test the whole sentence: are you naming the control or telling someone to act? The sentence will usually make the correct form obvious.

Rewrite help: templates and ready rewrites

Use these templates depending on whether you're naming the control or giving an instruction. Below are weak phrasings and clearer alternatives you can reuse.

UI label template: [Label] - avoid mentioning "checkbox" in the label itself.
Instruction template: Check the box for [reason].
Technical template: Toggle the checkbox to enable [feature].

Work - Rewrite: Weak: "Please check the box if you agree to the data policy." → Clear: "If you agree to the data policy, check the box to continue."
Work - Rewrite: Weak: "Select your meal by clicking the check box next to the option." → Clear: "Select your meal by clicking the checkbox next to the option."
School - Rewrite: Weak: "There is a check box next to each name for attendance." → Clear: "There's a checkbox next to each name for attendance."
Casual - Rewrite: Weak: "To opt out, untick the check box." → Clear: "To opt out, uncheck the checkbox."
Work - Rewrite: Weak: "Use the check box to allow cookies." → Clear: "Use the checkbox to allow cookies."
Rewrite: Weak: "Click the check box on each page." → Clear: "Click the checkbox on each page."

Fix your sentence: checklist and quick decision steps

Checklist: 1) Are you naming the control? → checkbox. 2) Are you telling someone to act? → check the box. 3) Need a hyphen? → usually no. 4) Is the verb natural for the platform (click/select/tap/check/tick)? 5) Match UI capitalization with your style guide.

Step 1: Identify noun vs. verb phrase.
Step 2: Choose closed compound for names, two words for actions.
Step 3: Pick the verb and casing that match your context.

Wrong: I can't select the check box in the form.
Rewrite: I can't select the checkbox in the form. (If you mean the action: I can't check the box in the form.)

Similar mistakes to watch for

Watch for related confusions: tick box (UK), radio button (different control), and checkmark vs. check mark. Also avoid redundant slips like "click the checkbox box".

tick box (UK) - common in British English; in apps, checkbox is more common.
radio button - a mutually exclusive control, not a checkbox.
checkmark vs. check mark - decide on one spelling and use it consistently.

Usage: Wrong: "Click the radio checkbox to choose one option."
Right: "Use the radio button to choose one option; use a checkbox for multiple selections."
Usage: UK note: "tick box" is common in manuals; in software/UI, "checkbox" is widely used.

Memory trick and quick practice

Mnemonic: "Name it closed, do it open." If you're naming the control, close the compound (checkbox). If you're giving an instruction, leave it open (check the box).

Say these aloud to test which form sounds natural: "Click the checkbox." / "Check the box if you agree." / "There are two checkboxes."

"Name it closed" = checkbox.
"Do it open" = check the box.
Speaking examples aloud helps you choose the natural form for the context.

FAQ

Is it checkbox or check box?

Use checkbox (one word) for the UI control. Use check the box (two words) when check is a verb and box is a noun.

Can I write check-box with a hyphen?

Hyphenation is uncommon. Avoid check-box unless a house style requires hyphens for compound modifiers.

What's the plural of checkbox?

The plural is checkboxes. Example: "There are three checkboxes on the form."

Should UI labels say "checkbox" or "check the box"?

UI labels generally omit the word "checkbox" and use a concise label (e.g., "Subscribe"). Reference "checkbox" in documentation or settings, not in the label itself.

Does British English prefer "tick box"?

British English often uses "tick box" in general contexts. In software/UI contexts, checkbox is common. Choose one term for your product and be consistent.

Quick final tip

If you're unsure, run the checklist: are you naming a control or issuing an instruction? That single question usually gives the right form.