Ring Window and Door Contact Sensor (2nd gen) is the top pick among smart door and window sensors under $40, rated 4.7 stars across 29,332 customer reviews.
RingWindow and Door Contact Sensor (2nd gen)
25% OFF$19.99$14.99
EufyEntry Sensor
$29.99
AqaraDoor and Window Sensor
$18.99
YoLinkLoRa Smart Outdoor Contact Sensor
$24.99
SwitchBotContact Sensor
$15.99
AeotecMultipurpose Sensor
$38.99
PhilipsHue Secure Contact Sensor
$39.99
AqaraDoor and Window Sensor P2
10% OFF$29.99$26.99
SonoffDW2-WIFI
$12.23
CentraliteMicro Door Sensor
$40.00
AeotecRecessed Door Sensor 7
8% OFF$39.99$36.99
EveDoor & Window
28% OFF$43.95$31.80
HeimanWindow Door Alarm
15% OFF$19.98$16.98
ArloAll-in-One Sensor
$29.59
AeotecDoor Window Sensor 7
$34.99
SonoffSNZB-04 ZigBee Wireless Door/Window Sensor
$17.99
MerossSmart Door and Window Sensor
18% OFF$21.99$17.99
SonoffSNZB-04P ZigBee Door/Window Sensor
$18.99
ArreTuo Contact Sensor
$29.99
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Frequently asked questions
What are the best smart door and window sensors under $40?
Ring Window and Door Contact Sensor (2nd gen), Eufy Entry Sensor and Aqara Door and Window Sensor lead our ranking of smart door and window sensors under $40, ordered by customer rating weighted by how many reviews back it. The full list compares 19 products in this price range.
How many smart door and window sensors cost less than $40?
This page tracks 19 smart door and window sensors under $40 from 14 brands, with prices starting at $12.23.
Are these prices up to date?
Prices come from each product's Amazon listing and are re-checked continuously, so every card shows the latest price we have. A product whose price rises above $40 drops off this list on the next update.
Looking for more than $40?
See all the door & window sensors in the catalog, compared side by side on specs, price and rating.