Strikethrough vs Underline vs Bold: When to Use Each
These three styles get reached for interchangeably a lot, but they don't mean the same thing, and picking the wrong one sends a slightly off signal even when the text itself is right. Bold says "pay attention to this." Underline, online at least, usually says "click this." Strikethrough says "this used to apply, but doesn't anymore." Here's how to tell them apart, when each one is actually the right call, and where they can safely be combined.
The Short Answer
If you're in a hurry: use bold to make the single most important word or phrase in a line stand out. Use strikethrough to show something was removed, corrected, or completed while keeping it visible. Avoid underline for emphasis entirely in anything read on a screen, since it's become shorthand for "this is a clickable link" almost everywhere text appears online. Each of the sections below explains the reasoning in more detail.
Bold: For Emphasis and Hierarchy
Bold works by making text visually heavier than what's around it, which is exactly why it's most effective when used sparingly — a page that's mostly bold has no hierarchy left, since nothing stands out from anything else. It's the right choice for a headline, a key term the first time you use it, or the one instruction in a paragraph you most need someone to notice, like a deadline or a warning.
Underline: A Style With a History Problem
Underline has a specific baggage that bold and strikethrough don't: since the earliest days of the web, underlined blue text has meant "this is a hyperlink," and that association is strong enough that underlining plain text for emphasis on a screen genuinely confuses readers, who instinctively try to click it. It's still legitimate in handwriting, formal print documents, and a few specific typographic conventions (like underlining a book title in a handwritten note where italics aren't available), but for anything digital, bold or italic almost always communicates emphasis more clearly than underline does.
Strikethrough: For Marking Something as Past or Wrong
Strikethrough is the only one of the three that changes the meaning of the text rather than just its visual weight — it tells the reader "this is no longer accurate, but I want you to see what it used to say." That's what makes it right for a crossed-out old price, a corrected typo left visible for effect, or a completed to-do item you're keeping as a record rather than deleting.
Can You Combine Them?
Yes, and it's common to see two at once. A crossed-out old price is often also slightly smaller or lighter than the new price next to it, which is really strikethrough plus a visual de-emphasis rather than bold — the opposite pairing, bold strikethrough, shows up in documents where someone wants a deleted item to still draw attention (a striking example: crossing out a rejected proposal option in bold so it's clearly seen and clearly rejected at the same time). Underline paired with either is rare outside of very deliberate formal styling, again because of the link association.
A Decision Guide
Ask yourself what the text is doing. If it's a change (something removed, corrected, or completed), strikethrough is right. If it's the most important phrase in the sentence and you want a reader's eye to land on it first, bold is right. If it's an actual link, underline (or your platform's native link styling) is correct — and if it's none of those, plain text is usually the better choice over reaching for a style out of habit. When in doubt, apply nothing and reread the sentence; if it still reads clearly, it probably didn't need a style at all.
Common Mistakes
The most frequent mistake is using bold for entire sentences or paragraphs instead of single words or short phrases, which erases the contrast that makes bold useful in the first place. The second most common is underlining for emphasis in digital text, which reads as a broken or misplaced link to a meaningful share of readers. The third is deleting something outright instead of using strikethrough when the whole point of the edit is to show what changed, like in a shared document, a price comparison, or a before-and-after caption.
How This Plays Out in Real Writing
A product page that bolds every feature name, underlines every benefit, and strikes through nothing tells a reader nothing about what actually matters most, because everything is competing for the same level of attention. The same page with one bold phrase per section, no underline outside of actual links, and strikethrough reserved for an outdated price or spec reads as far more deliberate — readers trust formatting that's used consistently more than formatting that's used everywhere.
Frequently Asked Questions
Why shouldn't I underline text that isn't a link?+
Because underlined text online is so strongly associated with hyperlinks that readers will often try to click it, and when it doesn't respond, it reads as a broken link rather than as emphasis — the opposite of the effect you're going for.
Can strikethrough and bold be used together?+
Yes — combining them keeps a deleted or outdated item visually prominent instead of fading it out, which is useful when you specifically want a crossed-out item to still catch the reader's eye rather than blend into the background.
Which style is best for a to-do list?+
Strikethrough, almost always. It marks a task as done while keeping the full list intact and readable, which preserves a record of what's been completed — bold would just make finished and unfinished tasks look equally urgent, and underline risks looking like a broken link in a digital list.
Is italic a safer alternative to underline for emphasis?+
Generally yes. Italic doesn't carry the same "click me" association underline does online, and it's well-supported for light emphasis in both formal writing and casual text, including Italic Text Generator output pasted anywhere plain text is accepted.
What did people use underline for before hyperlinks existed?+
In typewritten and handwritten documents, underline was the standard way to indicate a book or publication title, since italics weren't always available on a typewriter. That convention still shows up in some formal or academic styles today, even though italics has mostly replaced it in print.
Does it matter which one I use in a casual text message?+
Less than in a formal document, but the same logic still holds loosely — bold for the one word you want to land, strikethrough for a joking self-correction, and underline skipped entirely unless you're sending an actual link, since most messaging apps render links with their own underline automatically anyway.
Related Tools
Strikethrough Text Generator
Add a line through your text for Instagram, Twitter, Discord, and more.
Try it →Bold Text Generator
Make your text bold anywhere, even where bold formatting isn't normally allowed.
Try it →Underline Text Generator
Add an underline to your text without HTML or a text editor.
Try it →