flattening stone
Skip itA small market ($70K/yr) — this niche doesn't clear our bar today.
Avg price
Incredible$27.99avg listing price — sweet spot $15–$100
Price range
Great$9.88–$95.41cheapest to priciest tracked listing — scored on the share inside $15–$100
Returns
Great1.3%return rate — above 5% kills the launch gate
Conversion
Good6.3%search→purchase rate — share of searches ending in a sale
Review moat
Good1,170avg incumbent reviews — the moat a new listing must climb
Brand share
Good73%top-5 brand share — brands hold most of the demand
Quality gap
Good4.4★avg incumbent rating — lower means beatable quality
Competition
Bad71%top-5 click share — a locked-up shelf
Growth
Bad-12.2%90-day search growth — must beat 0% to launch
Market size
Bad$70K$70K/yr · 39K searches
According to Flapen's Amazon United States niche tracking, flattening stone is a $70K/yr Amazon United States market (39K searches/yr). The top 5 brands hold 73% of demand. Demand peaks in Jan–May–Dec. Verdict: Skip it — 48/100.
Data updated Jul 29, 2026 · scored weekly · How we score niches
flattening stone market data
- Units sold / yr
- 2K–3K
- avg 100–250/product
- Revenue / yr
- $56K–$70K
- units × avg price
- Conversion rate
- 6.3%
- Avg BSR
- #275
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 88%
- Out of stock
- 4.0%
- Avg brand age
- 69 months
- Avg seller age
- 170 days
Competition & brand share
The top 5 products capture 71% of clicks — a locked-up shelf that new listings rarely crack.Brands
16 flat
Sellers
46
Top-5 brand share
73%
Top 20: 100%
Top-5 click share
71%
Top 20: 100%
Open market
23%
- Sharp Pebble25%
- WOCHOLL20%
- Naniwa17%
- Angerstone6%
- SHARPAL4%
- Intelitopia4%
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — -12.2% search growth over the last 90 days.Peak months: Jan, May, Dec · busiest ÷ quietest = 1.6×
Top flattening stone search terms
- flattening stone26K/yr
- whetstone flattening stone7K/yr
- whetstone flattener3K/yr
- truing stone4K/yr
Top flattening stone 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 17 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Sharp Pebble Flattening Stone - Dual Grit 120/320 Whetstone Flattener
Sharp Pebble$28.544.3★1,558 rev
WOCHOLL Flattening Stone with Grooves and Grit Grooves for Re Levelling Any Whet stones Oil Stones Waterstones (7.1x2.4x1in)
WOCHOLL$13.924.3★149 rev
Naniwa Straightening Stone IO-1142 Grit 220
Naniwa$22.594.6★726 rev
Angerstone Dual Grit Coarse/Fine Flattening Stone Set - Two Sharpening Stones Flattener - Whetstone Fixer with Grooves for Re-Levelling Any Whet stones Oil Stones Waterstones
Angerstone$15.564.3★380 rev
SHARPAL 145H 10 x 4 Inch Diamond Lapping Plate Whetstone Flattener
SHARPAL$95.414.6★177 rev
Newest
by launch date
POWERTEC Large Flattening Stone 120/320 Dual Grit Sharpening Stone Flatener Diamond Grooves Sharpening Stone Fixer for Whetstone Wet stone Waterstone Oil Stone (72124)
POWERTEC$21.62141 rev
Whetstone Flattening Stone. Sharpening Tool for Re-leveling Waterstones Whetstones Oil Stones | Extra Coarse #100 Grit Fixer Flattener Sharpener.
Koja$9.8815 rev
SHARPAL 145H 10 x 4 Inch Diamond Lapping Plate Whetstone Flattener
SHARPAL$95.41177 rev
Amazon Basics Whetstone Knife Sharpening Stone Set Double-sided 400/1000 and 3000/8000 Grit Stones Flattening Stone with Angle Guide Non-Slip Bamboo Base 3 Count Black & Grey
Amazon Basics$25.471,429 rev
HMPLL Knife Sharpening Stone Set Professional Whetstone 4 Side Grit 400/1000 3000/8000 Whetstone Knife Sharpener Stone Set Include Non-slip Base Leather Strop Flattening Stone & Angle Guide
HMPLL$22.723,854 rev
Trending
90-day click momentum
Flattening Stone for Re-Leveling Sharpening Stones or Waterstones Re-Level Whetstone Fixer Tool Grinding Stone Black
Tknoocp$13.484.5★
Trend 8 Diamond Sharpening & Flattening Stone Double Sided (180/600 Grit)
TREND$40.174.2★
Shun Leveling Stone
Shun$37.134.7★
WOCHOLL Flattening Stone with Grooves and Grit Grooves for Re Levelling Any Whet stones Oil Stones Waterstones (7.1x2.4x1in)
WOCHOLL$13.924.3★
Naniwa QA-0160 Whetstone for Refacing (Grooved)
Naniwa$23.143.9★
What buyers say about flattening stone
What buyers praise and complain about, mined from review topics.What buyers love
“Sharp Knifes”
“Excellent quality”
“Great Deal”
“Works as intended”
“Easy to use”
“good diamond flatting stone works great”
“Seems durable”
“It can Cutttttt”
“Perfect size”
“Quality Materials: The stones themselves feel high-quality and wear evenly”
What buyers complain about
“Cheaply made”
“surface, which is impossible to use for sharpening”
“May need a breaking in phase”
“The bases being wooden probably isn't the best material to be used for stones that absorb water”
“Does not come with advertised items”
“Small”
“The angle guide dose not work well”
“It takes a bit of effort”
“Followed the rather weak instructions exactly”
“$30 price seemed pretty cheap”
Top return reasons
Common questions
- Is flattening stone profitable to sell on Amazon United States?
- The niche generates $70K/yr across 17 tracked products. 90-day search growth is -12.2%. Flapen's verdict: Skip it (48/100).
- How competitive is the flattening stone niche?
- 16 brands and 46 sellers compete. The top 5 products take 71% of clicks and top 5 brands hold 73% of demand.
- What do buyers complain about in flattening stone?
- Top complaints mined from reviews: Quality-Overall, Sharpness, Durability. The return rate is 1.3%.
- When does demand for flattening stone peak?
- Demand peaks in Jan–May–Dec; the busiest month runs 1.6× the quietest.
- What does it cost to enter the flattening stone niche?
- Listings span $9.88–$95.41; the average listing price is $27.99 (sweet spot $15–$100). The average incumbent carries 1,170 reviews — the moat a new listing must climb.