Is 21st birthday decorations for her profitable to sell on Amazon United States?

The niche generates $1.8M/yr across 81 tracked products. 11 of 29 products launched in the last 360 days are still selling. 90-day search growth is -13.3%. Flapen's verdict: Worth a look (63/100).

How competitive is the 21st birthday decorations for her niche?

63 brands and 82 sellers compete. The top 5 products take 27% of clicks and top 5 brands hold 28% of demand.

What do buyers complain about in 21st birthday decorations for her?

Top complaints mined from reviews: Quality-Overall, Durability, Size-Overall. The return rate is 2.6%.

When does demand for 21st birthday decorations for her peak?

Demand peaks in Sep; the busiest month runs 2.0× the quietest.

What does it cost to enter the 21st birthday decorations for her niche?

Listings span $4.73–$42.81; the average listing price is $13.51 (sweet spot $15–$100). The average incumbent carries 814 reviews — the moat a new listing must climb.

21st birthday decorations for her

Worth a look

Shows no brand lock-in (top 5 brands take 28% of clicks), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.

Brand share

Incredible28%

top-5 brand share — no brand owns this niche

Market size

Great$1.8M

$1.8M/yr · 3.6M searches

Competition

Great27%

top-5 click share — an open shelf

Price range

Good$4.73–$42.81

cheapest to priciest tracked listing — scored on the share inside $15–$100

Review moat

Good813.69

avg incumbent reviews — the moat a new listing must climb

Avg price

Good$13.51

avg listing price — sweet spot $15–$100

Returns

Good2.6%

return rate — above 5% kills the launch gate

Conversion

Okay3.7%

search→purchase rate — share of searches ending in a sale

Quality gap

Okay4.6★

avg incumbent rating — lower means beatable quality

Growth

Bad-13.3%

90-day search growth — must beat 0% to launch

Signals No Dominant Brand

According to Flapen's Amazon United States niche tracking, 21st birthday decorations for her is a $1.8M/yr Amazon United States market (3.6M searches/yr). The top 5 brands hold 28% of demand. Demand peaks in Sep. Verdict: Worth a look — 63/100.

Data updated Jul 23, 2026 · scored weekly · How we score niches

21st birthday decorations for her market data

Units sold / yr: 100K–125K; avg 1,000–1,250/product
Revenue / yr: $1.4M–$1.7M; units × avg price
Conversion rate: 3.7%
Avg BSR: #1,378
Page quality: 0%
Prime: 100%
Sponsored: 85%
Out of stock: 1.6%
Avg brand age: 29 months
Avg seller age: 165 days

Competition & brand share

Clicks spread well past the top 5 (27% combined) — an open shelf where new products get seen.

Brands

63 falling

Sellers

Top-5 brand share

28%

Top 20: 68%

Top-5 click share

27%

Top 20: 57%

Open market

67%

Ziwenhu6%
Juesly6%
PLOZZY5%
KICOSY5%
WowBefun5%
Trgowaul5%

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -13.3% search growth over the last 90 days.

Peak months: Sep · busiest ÷ quietest = 2.0×

Open Trend

Top 21st birthday decorations for her search terms

21st birthday decorations1.4M/yr +0.2%2.5% conv.
21st birthday490K/yr -4.4%1.7% conv.
21st birthday decorations for her339K/yr -7.7%2.8% conv.
21 birthday decorations for her96K/yr -4.7%2.3% conv.
happy 21st birthday decorations93K/yr +10.6%2.8% conv.
21st birthday decor44K/yr -2.3%1.5% conv.
happy 21st birthday32K/yr -2.9%1.7% conv.
21 birthday29K/yr -1.6%3.2% conv.
21st17K/yr -19.8%0.6% conv.
21st birthday for her16K/yr -6.8%1.4% conv.

All search terms

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.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 24 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

Ziwenhu Funny 21st Birthday Card Gift Decorations for Her Him

Ziwenhu$5.494.8★2,134 rev

21st Birthday Decorations for Her 50Pcs PRE-STRUNG Rose Gold Black Party Set-21 Years Old Crown and Sash Banner Hanging Swirl Backdrop Decor CakeTopper Age Candle Balloons Paper Fans PRE-ASSEMBLED

PLOZZY$20.444.7★423 rev

21st Birthday Crowns and Sash for Women Birthday Sash Princess Tiara Headband Rose Gold Crown with Combs Crystal Tiaras Headpieces for Party Hair Accessories Gifts

KICOSY$8.484.6★204 rev

Happy 21st Birthday Card Gifts Decorations for Women Men Her Him | Funny Happy Unique 21 Year Old Gifts Ideas | Back In 2005

WowBefun$5.274.7★244 rev

Semato 21st Birthday Decorations for Her Sash and Crown Tiara Kit Rose Gold 21st Birthday Gifts for Girls Party Supplies

Semato$11.934.8★246 rev

Newest

by launch date

Happy 21st Birthday Decorations For Her Pink Rose Gold 21st Birthday Gifts For Her 21st Birthday Sash Crown Cake Topper Number Balloons Banner Backdrop Hanging Swirls Birthday Party Supplies

RTHPY$19.51148 rev

5mo ago

Happy 21st Birthday Card Gifts Decorations for Women Men Her Him | Funny Happy Unique 21 Year Old Gifts Ideas | Back In 2005

WowBefun$5.27244 rev

7mo ago

21st Birthday Decorations Black & Rose Gold Party Kit for Her with Birthday Sash Crown Banner Balloons Back in 2005 Backdrop Cake Toppers Candles Happy 21st Birthday Decorations

PopularLdo$20.1116 rev

7mo ago

21st Birthday Decorations for Her Rose Gold Happy 21st Birthday Decorations for Girls 21 Sash and Crown Banner Fringe Curtains Hanging Paper Fans 21 Year Old Party Supplies Set

Juesly$22.2835 rev

10mo ago

51Pcs 21st Birthday Decorations for Her Champagne Gold Happy 21st Birthday Decorations for Girls 21 Sash and Crown Banner Fringe Curtains Hanging Paper Fans 21 Year Old Party Supplies Set

Juesly$21.34170 rev

10mo ago

What buyers say about 21st birthday decorations for her

What buyers praise and complain about, mined from review topics.

What buyers love

Quality-Overall27%

“Product is beautiful”

Value For Money11%

“Great Value”

Color10%

“The color is pretty”

Gifting Purpose9%

“Cute Gift”

Advertised Vs Actual Product7%

“As described”

Fun/Entertainment Experience5%

“very entertaining”

Assembly/Installation4%

“Easy to put together”

Design-Overall4%

“Very nice decorations”

Durability3%

“Held up well”

Ease Of Use3%

“Easy to use”

What buyers complain about

Quality-Overall14%

“Not a good quality product, breaks eassy”

Durability11%

“Broke”

Size-Overall10%

“Too small”

Adhesion/Stickiness6%

“since the adhesive didn't stick”

Advertised Vs Actual Product6%

“Not what is advertised”

Strength4%

“They break too easily”

Assembly/Installation4%

“NOT ASSEMBLED AND HARD TO DO”

Thickness4%

“Thinner material”

Inflation/Deflation4%

“super upset the balloons keep popping”

Value For Money4%

“looks more expensive than it is”

Top return reasons

Size-Overall24%

Color19%

Value For Money12%

Advertised Vs Actual Product9%

Quality-Overall6%

Defective Material/Parts4%

Functionality-Overall2%

Adhesion/Stickiness2%

Material Quality2%

Assembly/Installation2%

Common questions

Is 21st birthday decorations for her profitable to sell on Amazon United States?: The niche generates $1.8M/yr across 81 tracked products. 11 of 29 products launched in the last 360 days are still selling. 90-day search growth is -13.3%. Flapen's verdict: Worth a look (63/100).
How competitive is the 21st birthday decorations for her niche?: 63 brands and 82 sellers compete. The top 5 products take 27% of clicks and top 5 brands hold 28% of demand.
What do buyers complain about in 21st birthday decorations for her?: Top complaints mined from reviews: Quality-Overall, Durability, Size-Overall. The return rate is 2.6%.
When does demand for 21st birthday decorations for her peak?: Demand peaks in Sep; the busiest month runs 2.0× the quietest.
What does it cost to enter the 21st birthday decorations for her niche?: Listings span $4.73–$42.81; the average listing price is $13.51 (sweet spot $15–$100). The average incumbent carries 814 reviews — the moat a new listing must climb.