What is #21st used for?

#21st is a popular hashtag used on Instagram, TikTok, YouTube, and LinkedIn to categorize content. It has 3 related hashtags. The best hashtags to pair with #21st are: #21stbirthday, #birthday, #party.

What are the best hashtags to use with #21st?

Based on analysis of 19 posts, the top hashtags to combine with #21st are: #21stbirthday, #birthday, #party. These have high relevance scores averaging 28% and are used by 65% of top-performing posts.

How many hashtags should I use with #21st?

For Instagram, use 20-30 hashtags including #21st. For TikTok, use 3-5 hashtags. For YouTube, use 3-5 in description. For LinkedIn, keep it to 3-5 professional hashtags. Studies show this can increase engagement by +20%.

How do I use #21st on Instagram?

On Instagram, add #21st in your caption or first comment with 20-30 related hashtags. Best tags to combine: #21stbirthday, #birthday, #party. Use in Stories and Reels for extra discovery.

Does #21st work on TikTok?

Yes! Use #21st with 3-4 related hashtags like #21stbirthday and #birthday. Posts using #21st see 3x more reach on average. TikTok prioritizes content quality, so pair with trending sounds.

Can I use #21st on YouTube?

Yes, add #21st to your video title — first 3 hashtags appear above the title. Include related tags like #21stbirthday, #birthday in your description. Works great for YouTube Shorts.

Is #21st still popular in 2026?

Yes! #21st remains highly popular in 2026 with 3 related hashtags and 19+ posts analyzed. 65% of top-performing posts in this niche use #21st or related tags.

What hashtags are similar to #21st?

Similar hashtags to #21st include: #21stbirthday, #birthday, #party. These share 28% average relevance and can increase reach by 3x when used together.

#21st

Discover 3 trending hashtags related to #21st for Instagram, TikTok, YouTube & LinkedIn in 2026.

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Best hashtags to use with #21st:

#21stbirthday, #birthday, #party

Based on analysis of 19 posts • 3 related hashtags found

📊 #21st Statistics & Insights

65%

of top posts use related tags

avg reach with #21st

+20%

engagement boost

optimal hashtags (IG)

Data based on analysis of 19+ posts using #21st • Updated 2026

Related Tags

Post Connections

28%

Avg Relevance

Copy & Paste #21st Hashtags

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Instagram Hashtags

30 hashtags • Caption or comment

#21st #21stbirthday #birthday #party

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TikTok Hashtags

5 hashtags • Video caption

#21st #21stbirthday #birthday #party

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YouTube Hashtags

5 hashtags • Title & description

#21st #21stbirthday #birthday #party

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LinkedIn Hashtags

5 hashtags • Professional posts

#21st #21stbirthday #birthday #party

Related Hashtags for #21st

Click any hashtag to explore its related tags

3 tags

1#21stbirthday13%

2#birthday45%

3#party25%

How to Use #21st on Each Platform

Platform-specific strategies to maximize your reach with #21st

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Instagram

20-30 hashtags recommended

✓Add #21st in your caption or first comment
✓Mix #21stbirthday, #birthday, #party for best reach
✓Use in Stories and Reels for extra discovery
✓Combine popular hashtags with niche-specific ones
→Pro tip: Save hashtag sets for quick reuse

🎵

TikTok

3-5 hashtags recommended

✓Less is more — use #21st + 3-4 related tags
✓Check FYP trends for #21st variations
✓Pair with trending sounds for algorithm boost
✓Content quality matters more than hashtag count
→Pro tip: Add hashtags at end of caption

▶️

YouTube

3-5 hashtags recommended

✓Add #21st in video title for visibility
✓First 3 hashtags show above video title
✓Include in description with related: #21stbirthday, #birthday
✓Add to video tags for search ranking
→Pro tip: Use Shorts with hashtags for discovery

💼

3-5 hashtags recommended

✓Keep #21st professional and industry-relevant
✓Add hashtags at the end of your post
✓Follow #21st to engage with community
✓Combine with thought leadership content
→Pro tip: Check hashtag followers before using

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Explore More Hashtags

Best #21stbirthday hashtags Best #birthday hashtags Best #party hashtags

#21st

Best hashtags to use with #21st:

📊 #21st Statistics & Insights

Copy & Paste #21st Hashtags

Related Hashtags for #21st

How to Use #21st on Each Platform

Instagram

TikTok

YouTube

LinkedIn

People Also Ask About #21st

What is #21st used for?

How many hashtags should I use with #21st?

What are the best hashtags to use with #21st?

Does #21st work on TikTok?

How do I use #21st on Instagram?

Is #21st still popular in 2026?

What hashtags are similar to #21st?

How to get more likes with #21st?

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