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Extech 407777 Moisture Meter
Our Score:

Discontinued by the manufacturer
Extech 407777 Moisture Meter At A Glance

This meter exhibits a critical flaw—namely its inability to give reliable readings below 12% moisture content. This flaw renders the meter essentially unusable for a number of common applications, including for flooring installations and furniture making. We deducted two stars from our overall rating to reflect this critical flaw.

The Extech 407777 is a pin-style moisture meter that includes a push cable accessory and a large, easy-to-read digital readout. The meter is simple-to-use and offers many features, such as a data hold function, calibration check button, and built-in temperature adjustment. This meter appears solid but is heavier and bulkier than most of the other wood meters we tested.

The user should keep in mind that this meter has some significant limitations. Most notably, it is not capable of measuring moisture content (MC) below 9%, so it won’t be very useful for applications where measuring materials with low MC is a must.

Floor installers, furniture makers, and others who need to measure wood at low MC should look elsewhere.


  • Easy to use with large, easy-to-read LED display
  • Feature-rich with data hold button, built-in temperature adjustment, and a calibration button


  • Not able to take measurements below 9% MC
  • Manual provides very little instruction about use
  • No adjustment available for wood species

Objective Evaluation – Overall Score 3.8 out of 5.0

Objective test summary results for the Extech 40777 wood moisture meter, achieving objective score of 88%

Accuracy – 3.8 out of 5.0

This meter provided reasonably accurate readings from about 12% through about 22% MC when compared to ASTM D4442 oven dry standards. Below 12% MC, this meter’s accuracy is questionable due to significantly high readings.

Splatter chart showing the Extech 407777 provided reasonably accurate readings from about 12% through about 22% MC

Learn about our accuracy test procedures

Surface Moisture – 1.0 out of 5.0

Surface moisture caused this meter to post readings over 7% higher than the baseline. These surface moisture results indicate that operating this meter in high humidity environments where condensation may form on the surface could lead to questionable readings.

Bar chart showing that surface moisture caused the Extech 407777 Moisture Meter to post readings 7% above baseline

Learn about our surface moisture test procedures

Meter Temperature – 5.0 out of 5.0

Meter temperature had relatively little effect on this meter’s MC readings. Regardless of meter temperature, no observable change in readings was found in the presence of wood at low MC. A low meter temperature of 34.8° F in the presence of high MC decreased the readings by less than 0.5%. Similarly, a high meter temperature of 110° F in the presence of high MC, increased the readings by less than 0.5%.

Extech 407777 Meter Temperature

Learn about our meter temperature test procedures

Wood Temperature – 5.0 out of 5.0

Wood temperature affected this meter’s readings by only a small amount.

A low wood temperature of 33° F in the presence of low MC showed less than a 1% decrease in the reading when compared to the room temperature reading. In the presence of high MC, the reading did not change appreciably.

A high wood temperature of 110° F in the presence of low MC showed very little change in the reading when compared to the room temperature reading. In the presence of high MC, the reading increased by just under 1%.

Extech 407777 Wood Temperature

Learn about our wood temperature test procedures

Reading repeatability – 4.0 out of 5.0

The readings of this meter were not entirely repeatable, showing some tendency to vary.

Line chart showing readings of the Extech 407777 meter were not entirely repeatable, showing some tendency to vary.

Learn about our repeatability testing procedures

Drift – 5.0 out of 5.0

Readings for this meter showed very little tendency to drift, with readings that were only slightly lower after three seconds.

Bar chart showing readings for the Extech 407777 meter showed very little tendency to drift

Cable Interference – 5.0 out of 5.0

Testing of this meter indicated very little cable interference when using the cable accessory. Only a very small decrease in % MC was observed.

Bar chart showing testing of the Extech 40777 indicated very little cable interference when using the cable accessory.

Learn about our cable interference and drift testing procedures

Subjective Evaluation – Overall Score 3.3 out of 5.0

Extech 407777 subjective

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Ease of Use – 3.8 out of 5.0

This meter is easy to operate. Little use of the manual is needed except for using the tables to adjust for species and wood temperature.

Quality – 3.0 out of 5.0

Constructed of impact-resistant plastic, this meter is unlikely to break or malfunction with normal use. The non-insulated pins, however, are not very durable and break more frequently than one would expect.

Comfort – 3.0 out of 5.0

With an ergonomically-designed shape, this meter fits nicely in one’s hand. It is not compact enough to fit easily into a shirt pocket, but it does come with a hard case to protect the meter when transporting it from one job site to the next.

Versatility – 3.0 out of 5.0

This is a single-mode meter (pin), which is typical. The species correction table in the manual must be used to adjust for wood species. Readings on the display must be viewed upside down, which is not convenient when working in tight spaces. May be used with either the built-in pins or a slide hammer electrode accessory. Capable of being used with a variety of building materials in addition to wood.

Range – 2.3 out of 5.0

This meter reads from 6% to 40% and is not capable of taking measurements when the moisture content is below 6%. The accuracy of readings above 28% should be questioned.

Features – 3.5 out of 5.0

Readings precise to the nearest 0.1%. Features include the ability to store and average up to 100 readings, a built-in calibration check, an audible alarm to alert the user that the reading exceeds a selected value and three scales for use with different building materials. No low battery indicator. Slide hammer electrode accessory is available. Two types of contact pins available: non-insulated, which are pushed into the wood to their full length of 5/16th of an inch, and insulated pins, which can be driven to the desired measurement depth.

Customer Service – 4.5 out of 5.0

Extech offers a standard one-year warranty and a service center for repairs. Calibration services are also available but expensive. Response to telephone inquiries is fast, friendly, and professional.

Our review is based on Moisture Meter Experts independent evaluation of the meter, which was purchased by Moisture Meter Experts or provided free of charge by the manufacturer. By purchasing this meter through the links above, Moisture Meter Experts may be compensated either by your purchase directly from Moisture Meter Experts or from commissions from an affiliate. View our Review Procedures section to learn more about our proprietary evaluation procedure and expertise in the field of moisture meters.