21st birthday decorations for her
Worth a lookShows low returns (0.6%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.
Returns
Incredible0.6%return rate — above 5% kills the launch gate
Brand share
Great55%top-5 brand share — no brand owns this niche
Conversion
Great7.4%search→purchase rate — share of searches ending in a sale
Review moat
Good631.17avg incumbent reviews — the moat a new listing must climb
Quality gap
Good4.3★avg incumbent rating — lower means beatable quality
Competition
Good47%top-5 click share — leaders hold, buyers still browse
Market size
Good£282K£282K/yr · 494K searches
Growth
Bad-0.1%90-day search growth — must beat 0% to launch
Avg price
Bad£7.73avg listing price — sweet spot $15–$100
Price range
Bad£2.66–£14.19cheapest to priciest tracked listing — scored on the share inside $15–$100
According to Flapen's Amazon United Kingdom niche tracking, 21st birthday decorations for her is a £282K/yr Amazon United Kingdom market (494K searches/yr). The top 5 brands hold 55% of demand. Demand peaks in Jan. Verdict: Worth a look — 58/100.
Data updated Jul 27, 2026 · scored weekly · How we score niches
21st birthday decorations for her market data
- Units sold / yr
- 30K–40K
- avg 250–500/product
- Revenue / yr
- £232K–£309K
- units × avg price
- Conversion rate
- 7.4%
- Avg BSR
- #122
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 86%
- Out of stock
- 2.0%
- Avg brand age
- 24 months
- Avg seller age
- 185 days
Competition & brand share
The top 5 products take 47% of clicks — established leaders, but buyers still shop beyond them.Brands
23 falling
Sellers
47
Top-5 brand share
55%
Top 20: 97%
Top-5 click share
47%
Top 20: 89%
Open market
40%
- KIUEZIR21%
- VICTERR12%
- Yontree10%
- DEARLIVES7%
- OakTree6%
- onehous5%
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — -0.1% search growth over the last 90 days.Peak months: Jan · busiest ÷ quietest = 1.9×
Top 21st birthday decorations for her search terms
- 21st birthday decorations for her213K/yr
- 21st birthday decorations121K/yr
- 21st birthday banner44K/yr
- 21st birthday balloons26K/yr
- 21st birthday banners for her13K/yr
- 21st birthday banners12K/yr
- happy 21st birthday banner10K/yr
- 21st banners for her9K/yr
- 21 balloons for her8K/yr
- 21st decorations for her7K/yr
Top 21st birthday decorations for her products on Amazon
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 24 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
KIUEZIR Rose Gold 21st Floral Shaped Birthday Tiara & Sash Set for Women
KIUEZIR£7.444.8★26 rev
Rose Gold 21st Birthday Decoration for Her - Happy 21st Birthday Banner Triangle Flag Banner Number 21 Balloons Foil Curtains for Party Decorations
VICTERR£9.434.4★3,914 rev
21st Birthday Decorations Sage Green Gold White 21st Birthday Banners Balloons Cake Topper Sash Bunting Flags Number Helium Balloons for 21st Party Deco
Yontree£8.324.3★337 rev
21st Birthday Decorations Retro Pink Rose Gold - Double Digits 21 Party Supplies Set for Women & Girls birthday Banner Pennant Flags Cake Topper Balloon Assortment (21st Pink Birthday Set)
DEARLIVES£8.124.1★153 rev
Ledido LED Light Up Marquee Numbers Sign - Cool & Warm Light up Numbers for 21st Birthday Decorations LED Number Lights for Wedding Anniversary Grad Home Bedroom Table Wall Party Decor Number 21
Ledido£14.194.5★505 rev
Newest
by launch date
21st Birstday Decorations Women Set - 32 Pcs Black Rose Gold Banner Background Swirls Latex Foil Balloons Cake Toppers Table Decor For Her 21 Years Old Party Kit Supplies
LPPIIUSSU£11.687 rev
21st Birthday Decorations for Her Happy 21st Birthday Banner 40 inches 21 Foil Balloons Champagne Golden Bottle and Glass Gold Pink White and Confetti Balloons 21st Party Decorations for Girls
Lyuet£8.07187 rev
OLOSONG 4 Pcs 21st Birthday for Gifts Women 21st Birthday Sash Tiara - Rose Gold Birthday Queen Tiara and Sash for Women Heart shaped pink diamond glasses Wooden dice
OLOSONG£7.46196 rev
21st Birthday Decorations for Her Rose Gold Happy Birthday Banner with 6 Hanging Swirls Party Decor Supplies for Women 21st Birthday Table Decorations
TZMFHD£5.5710 rev
KIUEZIR Rose Gold 21st Floral Shaped Birthday Tiara & Sash Set for Women
KIUEZIR£7.4426 rev
Trending
90-day click momentum21st Birstday Decorations Women Set - 32 Pcs Black Rose Gold Banner Background Swirls Latex Foil Balloons Cake Toppers Table Decor For Her 21 Years Old Party Kit Supplies
LPPIIUSSU£11.684.3★
KIUEZIR Rose Gold 21st Floral Shaped Birthday Tiara & Sash Set for Women
KIUEZIR£7.444.8★
Belloxis 21st Birthday Gifts for Her Grip Socks Womens Cosy Socks Birthday Gifts for Women Sister Gifts for Girlfriend Daughter Gifts
Belloxis£5.674.6★
OLOSONG 4 Pcs 21st Birthday for Gifts Women 21st Birthday Sash Tiara - Rose Gold Birthday Queen Tiara and Sash for Women Heart shaped pink diamond glasses Wooden dice
OLOSONG£7.464.5★
21st Birthday Decorations for Her Happy 21st Birthday Banner 40 inches 21 Foil Balloons Champagne Golden Bottle and Glass Gold Pink White and Confetti Balloons 21st Party Decorations for Girls
Lyuet£8.074.2★
What buyers say about 21st birthday decorations for her
What buyers praise and complain about, mined from review topics.What buyers love
“Good value for money”
“Well made at a great price”
“You get what you see in the advert”
“colours was lovely”
“Good selection”
“Next day delivery, nice bright lights with warm white and bright white”
“the banner is good quality not the foil material so very satisfied”
“The mix of designs”
“durable”
“tiara is strong sturdy”
What buyers complain about
“Rubbish quality - broke on first use”
“Not worth £14.99”
“Rubbish quality - broke on first use”
“Obviously didn't realise till I was assembling it the night before my daughter's birthday”
“Seals on the balloons didn't stick so all balloons deflated by the time the party started”
“the one banner made out of strange material”
“flimsy really”
“Very thin and uncomfortable”
“heart shaped balloons are not shaped correctly”
“are a mixture of colour tones”
Top return reasons
Common questions
- Is 21st birthday decorations for her profitable to sell on Amazon United Kingdom?
- The niche generates £282K/yr across 29 tracked products. 0 of 5 products launched in the last 360 days are still selling. 90-day search growth is -0.1%. Flapen's verdict: Worth a look (58/100).
- How competitive is the 21st birthday decorations for her niche?
- 23 brands and 47 sellers compete. The top 5 products take 47% of clicks and top 5 brands hold 55% of demand.
- What do buyers complain about in 21st birthday decorations for her?
- Top complaints mined from reviews: Quality-Overall, Value For Money, Durability. The return rate is 0.6%.
- When does demand for 21st birthday decorations for her peak?
- Demand peaks in Jan; the busiest month runs 1.9× the quietest.
- What does it cost to enter the 21st birthday decorations for her niche?
- Listings span £2.66–£14.19; the average listing price is £7.73 (sweet spot $15–$100). The average incumbent carries 631 reviews — the moat a new listing must climb.