Is hydrometer profitable to sell on Amazon United States?

The niche generates $473K/yr across 36 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -12.3%. Flapen's verdict: Worth a look (60/100).

How competitive is the hydrometer niche?

26 brands and 51 sellers compete. The top 5 products take 42% of clicks and top 5 brands hold 54% of demand.

What do buyers complain about in hydrometer?

Top complaints mined from reviews: Size-Overall, Measurement/Reading Accuracy, Quality-Overall. The return rate is 1.2%.

When does demand for hydrometer peak?

Demand is steady year-round — the busiest month runs 1.3× the quietest.

What does it cost to enter the hydrometer niche?

Listings span $5.97–$22.94; the average listing price is $12.65 (sweet spot $15–$100). The average incumbent carries 12,296 reviews — the moat a new listing must climb.

hydrometer

Worth a look

Shows low returns (1.2%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.

Returns

Great1.2%

return rate — above 5% kills the launch gate

Conversion

Great10.2%

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

Brand share

Great54%

top-5 brand share — no brand owns this niche

Competition

Good42%

top-5 click share — leaders hold, buyers still browse

Market size

Good$473K

$473K/yr · 365K searches

Avg price

Good$12.65

avg listing price — sweet spot $15–$100

Quality gap

Good4.4★

avg incumbent rating — lower means beatable quality

Price range

Okay$5.97–$22.94

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

Review moat

Bad12,296.39

avg incumbent reviews — the moat a new listing must climb

Growth

Bad-12.3%

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

Signals No Dominant Brand

According to Flapen's Amazon United States niche tracking, hydrometer is a $473K/yr Amazon United States market (365K searches/yr). The top 5 brands hold 54% of demand. Verdict: Worth a look — 60/100.

Data updated Jul 15, 2026 · scored weekly · How we score niches

hydrometer market data

Units sold / yr: 30K–40K; avg 1,000–1,250/product
Revenue / yr: $380K–$506K; units × avg price
Conversion rate: 10.2%
Avg BSR: #13
Page quality: 0%
Prime: 100%
Sponsored: 94%
Out of stock: 0.0%
Avg brand age: 61 months
Avg seller age: 183 days

Competition & brand share

The top 5 products take 42% of clicks — established leaders, but buyers still shop beyond them.

Brands

26 rising

Sellers

Top-5 brand share

54%

Top 20: 96%

Top-5 click share

42%

Top 20: 86%

Open market

39%

Brewer's Elite15%
TempPro14%
Serundo Auto10%
KOSOEUR8%
ANFBYOH8%
JEDEW6%

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -12.3% search growth over the last 90 days.

No pronounced peak months · busiest ÷ quietest = 1.3×

Open Trend

Top hydrometer search terms

hydrometer353K/yr -12.3%8.8% conv.
hydrometers7K/yr -12.6%7.8% conv.
hydro meter3K/yr -15.3%7.4% conv.
hidrometro2K/yr -6.3%2.7% conv.

All search terms

Top hydrometer 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

Mini Hygrometer Thermometer Digital Humidity Meter Indoor/Outdoor Humidity Monitor Reptile Thermometer for Greenhouse Garden Cellar Fahrenheit()/ Celsius() 2 Pack

Serundo Auto$5.974.5★3,331 rev

Brewers Elite Hydrometer for Home Brew Beer Wine Mead and Kombucha - Deluxe Triple Scale Set with Hardcase and Cloth - Specific Gravity ABV Tester

Brewer's Elite$13.014.4★5,544 rev

TempPro TP50 Digital Hygrometer Indoor Thermometer Room Thermometer and Humidity Gauge with Temperature Humidity Monitor(Previously ThermoPro)

TempPro$10.884.6★154,357 rev

6-Pack Mini Hygrometer Indoor Humidity Meter Mini Digital Thermometer Humidity Gauge Meter Indoor Thermometer Hygrometer Monitor Fahrenheit () for Reptile Thermostat Jars Reptile Fridge

ANFBYOH$8.124.5★1,920 rev

Kosoeur Triple Scale Hydrometer Alcohol Hydrometer for Wine Mead Kombucha & Beer Mead Making Kit (ABV Tester Brix Specific Gravity Hydrometer) Hydrometer Alcohol Kit for Wine Brewing Supplies

KOSOEUR$10.504.3★362 rev

Newest

by launch date

CIMALAB Triple Scale Hydrometer Specific Gravity Hydrometer for Wine Making Mead Kombucha & Beer Mead Making Kit ABV Tester Brix Tester Hydrometer Alcohol Tester for Wine Making Supplies

CIMALAB$10.8538 rev

11mo ago

6 Pack Mini Hygrometer Indoor Humidity Meter Small Digital Thermometer Humidity Gauge Meter Indoor Thermometer Hygrometer Monitor Fahrenheit () for Thermostat Reptile Tank Mason Jars

JJMTDS$7.161,586 rev

1y ago

WWHAKO 4-Pack Mini Hygrometer Thermometer Indoor Outdoor Round Humidity Meter Small Digital LCD Monitor Thermometer Temperature Gauge Humidity Sensor () or () for Reptile Thermostat Jars

wwhako$7.94714 rev

1y ago

Mini Hygrometer Thermometer Digital Humidity Meter Indoor/Outdoor Humidity Monitor Reptile Thermometer for Greenhouse Garden Cellar Fahrenheit()/ Celsius() 2 Pack

Serundo Auto$5.973,331 rev

2y ago

6-Pack Mini Hygrometer Indoor Humidity Meter Mini Digital Thermometer Humidity Gauge Meter Indoor Thermometer Hygrometer Monitor Fahrenheit () for Reptile Thermostat Jars Reptile Fridge

ANFBYOH$8.121,920 rev

2y ago

What buyers say about hydrometer

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

What buyers love

Value For Money17%

“Great deal”

Advertised Vs Actual Product13%

“Better than expected”

Quality-Overall12%

“Excellent Product”

Ease Of Use12%

“Easy to Read”

Efficiency8%

“Does its job well”

Size-Overall6%

“Fit great”

Measurement/Reading Accuracy3%

“Seems accurate”

Battery Life3%

“Battery life is good so far”

Temperature Control2%

“Temperature is accurate”

Durability2%

“Durable and accurate”

What buyers complain about

Size-Overall16%

“Little bigger than I wanted”

Measurement/Reading Accuracy12%

“Inaccurate readings”

Quality-Overall9%

“Bad quality control”

Durability8%

“Doesn't Last”

Battery Life7%

“batteries don't last very long”

Functionality-Overall6%

“Did Not Work”

Connectivity-Overall4%

“Doesnt connect to app”

Value For Money3%

“Too expensive”

Display-Overall3%

“Display broken”

Advertised Vs Actual Product2%

“False advertising”

Top return reasons

Size-Overall16%

Functionality-Overall15%

Measurement/Reading Accuracy14%

Connectivity-Overall11%

Advertised Vs Actual Product9%

Display-Overall7%

Defective Material/Parts6%

Value For Money5%

Heating4%

Compatibility-Overall2%

Common questions

Is hydrometer profitable to sell on Amazon United States?: The niche generates $473K/yr across 36 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -12.3%. Flapen's verdict: Worth a look (60/100).
How competitive is the hydrometer niche?: 26 brands and 51 sellers compete. The top 5 products take 42% of clicks and top 5 brands hold 54% of demand.
What do buyers complain about in hydrometer?: Top complaints mined from reviews: Size-Overall, Measurement/Reading Accuracy, Quality-Overall. The return rate is 1.2%.
When does demand for hydrometer peak?: Demand is steady year-round — the busiest month runs 1.3× the quietest.
What does it cost to enter the hydrometer niche?: Listings span $5.97–$22.94; the average listing price is $12.65 (sweet spot $15–$100). The average incumbent carries 12,296 reviews — the moat a new listing must climb.