How to underline text in Instagram captions and bio
- Type it in the formatter Open the free Instagram text formatter in a browser on your phone or computer, and type or paste your text.
- Select the line and press U Select only the part to underline, like “N̲e̲w̲ ̲g̲u̲i̲d̲e̲ ̲o̲u̲t̲ ̲n̲o̲w̲”, and press U. On a computer, Ctrl/⌘+U works too. You can combine it with B or I.
- Copy it Press Copy text. Leave Keep empty lines on so the blank lines between paragraphs stay.
- Paste it into Instagram In a caption, comment or DM, paste where you type. For your bio, go to your profile, tap Edit profile, then Bio, paste, and save. Instagram’s own steps for the bio are in its help centre.
How to underline text in an Instagram Story
Stories and Reels have their own text tool with a choice of fonts, colours and effects, and Later notes that Instagram added many new fonts and text effects to it in late 2024. Underline isn’t one of the styles we could confirm there, so use the same paste method:
- Underline your text in the formatter and press Copy text.
- Open your Story and tap the text tool.
- Tap and hold in the text box until Paste appears, then paste.
- Pick a font and size, and check the line still sits under the letters before you share.
If all you want is to make a line stand out in a Story, a coloured text background or a different colour often does the job better than an underline.
How underlined text works on Instagram
Instagram’s caption box and bio take plain text: Later puts it simply, Instagram doesn’t offer built-in font options. The underline you see in captions is made of characters.
Unicode has a combining low line (U+0332). It draws a line under the character before it, and, as Wikipedia’s entry on underlining explains, a run of them joins into one underline. The formatter adds one after every letter and space you select: u̲n̲d̲e̲r̲l̲i̲n̲e̲. Since it’s text, it copies into Instagram, WhatsApp, a note or anywhere else.
Underline on Instagram, place by place
| Place | Underline? | Good to know |
|---|---|---|
| Captions | Yes | One line, usually the one you most want read |
| Bio | Yes | 150 characters. Keep your name and keywords plain |
| Comments and DMs | Yes | Fine for a title or a date; test on an older phone |
| Story text | Paste it in | Paste into the text tool, then check it in the Story font |
| Hashtags | No | An underlined hashtag is different characters, so it won’t work as a hashtag |
Bio limit and steps from Later (June 2026) and NapoleonCat (April 2025).
How to keep underlined text readable
Underline is the weakest of the copy-and-paste styles. Readers have learned it means “link”: browsers underline links by default, which Wikipedia notes too. So on a phone, an underlined line invites a tap that goes nowhere. Use it with that in mind:
- One line, not a paragraph. A date, a title, “read this first”. If you underline more, nothing stands out.
- Short words read best. Letters that hang below the line, like g, p and y, cross the underline and get harder to read.
- Prefer bold for meaning. If the words are the point, bold says it more clearly. Keep underline for a label or a heading.
- Don’t lock out screen readers. Styled characters can be skipped or read out one by one. Scope advises plain text whenever everyone must get the message.
- Check light and dark mode. Look at your post in both: a thin line can vanish against some photo backgrounds in Stories.
Underline not showing? Quick fixes
What went wrong, and the fix
| What you see | Why | What to do |
|---|---|---|
| No line after pasting | The plain text was copied | Use Copy text in the formatter, then paste again |
| The line has small gaps | The font draws one line per letter | Normal in some fonts. Shorter phrases look cleaner |
| Boxes instead of letters | An old phone or app lacks the character | Nothing to fix on your side; current phones show it |
| The line is under the spaces too | The formatter underlines spaces so the line runs on | Select just one word if you want gaps |
Underline in a real Instagram post
The caption underlines its first three words and nothing else. The carousel walks through a four-line bio, one line per slide.
In aiCarousels, the caption is written with the slides, and a dashed line shows where Instagram cuts it with “…more”, so you can see which line people read first. On the slides themselves, underline is real formatting: select the words, open More styles and pick Underline, on a computer or in your phone’s browser.
Other Instagram text styles
The same formatter gives you italics on Instagram with I, strikethrough with S, and bold with B in the Instagram bold text tool. Before you post, check how your bio and grid look together in the free Instagram feed planner. For carousels and the rest of your feed, see everything we’ve written about Instagram.
