Extech Clamp Meter Specs MA440

Editor Rating: 4.4/5

Great Product

Extech Clamp Meter Specs MA440

Reviewed by: Timothy Henderson

Last modified: May 27, 2023 @ 2:00 pm

  • Design
  • Functionality
  • Price

Extech MA440 Review Summary

Stripped back to the clamp meter basics and available under $50, the Extech MA440 targets the casual use DIYer and undemanding light contractor.

Incorporating a non-contact voltage detection system, the machine warns of live currents and components without having to touch against circuitry or wiring. And, with auto-shutoff and low battery warning, cell energy is protected, and you’re shielded against unexpected unit failure.

Trade contractors will welcome the CAT III certification rating, allowing the clamp meter to be utilized in high-energy three-phase environments. And with a brightly illuminated LCD screen, the tool is suitable for use in dimly lit locations.

The MA440 offers everything you’d expect in a budget clamp meter — capable of testing continuity, capacitance, frequency, and voltage. Its 1.2-inch jaw will cope sufficiently with standard cable diameters, and its minimalist dial and few buttons promise fuss-free operation.

This tool hails from the Extech stable — a US company backed by half a century of electrical testing know-how. The MA440 is the lowest-specced machine in its 440 series clamp meter lineup.


  • Weight – 9.3 ounces
  • Voltage – 600 volts
  • Current – 400 amps
  • Safety Rating –CAT III


  • Low impedance.
  • 1.2-inch jaw.
  • Auto-shutoff.


Affordably priced.
CAT III rated.
NCV detection.
1.2-inch jaw.


Lacks TRMS.
Cannot detect DC current.
No temperature feature.
Similar priced models offer more functions.

Features and Benefits of the Extech Clamp Meter MA440

It’s the lowest-specced machine in Extech’s 440 series — but does the MA440 Clamp Meter still have sufficient capabilities to please the demanding DIYer and light contractor?

Let’s see what this machine has under the hood.

CAT III Certification

Reassuring for the trade user, the MA440 from Extech is rated for CAT III (600-volt) environments — permitting use on industrial-grade three-phase systems. And, for the DIYer, this is more than sufficient for typical single-phase home situations.

Should you wish to learn more about CAT certifications — take a look at my complete guide to these safety ratings.

Non-Contact Voltage Detection

You don’t want to be unpleasantly surprised by live wires or components. Hence, it’s pleasing to see that the MA 440 clamp meter boasts non-contact voltage detection — or NCV.

This welcome safety feature means that the unit delivers both an audible and visual warning should the clamp head sense the presence of current or voltage — without having to make contact with the circuitry.

Not just reassuring for the pro user working in high-energy environments, but also beneficial for amateur operatives unsure of whether cables are live or dead.

Power Saving

Clamp meter failure mid-project can be both scary and hazardous — not knowing whether the exposed wires are flowing with high currents isn’t a desirable situation.

Therefore, it’s great to discover that the MA440 Clamp Meter incorporates a couple of power-saving features to shield against unexpected unit breakdown in the middle of the job.

Firstly, it has auto-shutoff — ensuring that the battery life is elongated by deactivating the tool when not used for 30 minutes. Secondly, it includes a low-battery warning function indicator — providing a visual alert when the power cell energy levels are close to depletion.

Backlit LCD

Whether a DIYer or trade pro, your circuit testing projects will not always be in well-lit areas.

The backlighted LCD screen of the Extech Clamp Multimeter MA440 delivers pleasing illumination for dim environments — permitting you to effortlessly read the display without recourse to a secondary work lamp. Just press the generously-sized side-mounted button, and the screen will illuminate.

Memory Hold

To ensure you don’t forget results and then have to retest your circuitry, the MA440 from Extech features memory hold technology. Allowing you to recall your most recent clamp meter job, you don’t have to waste time searching for a pen or paper to manually record readings.

1.2-Inch Jaw

The 1.2-inch jaw should be sufficient for most standard cables encountered in home improvement and trade work. And, for users utilizing the machine on PCBs (printed circuit boards), it will cope with components up to 500 MCM (multi-chip modules).

However, for many operators, the operational diameter may be restrictive — being too small for many high-energy transformer cables and steel-reinforced cords.

Multi-Function Capability

As a back-to-basics clamping multimeter, the MA440 can fulfill the majority of DIY and light contractor demands, including the testing of:

  • AC and DC voltage.
  • AC current.
  • Resistance.
  • Capacitance.
  • Frequency.
  • Continuity.
  • Diodes.

However, the lack of temperature and DC current capabilities may be off-putting for some users.

Included Accessories

In addition to the clamp meter unit, included with the MA440 purchase are:

  • Testing probe leads.
  • Carrying pouch.
  • Instruction manual.
  • 3 x AAA batteries.

Straightforward Operation

Appealing to the novice user, the fuss-free design of the MA440’s operation panel delivers effortless use. A single, thumb-turn dial permits you to switch between seven testing settings, and four buttons allow you to select memory, memory hold, reference value, and frequency/duty cycle toggle.

Extech Multi Clamp Meter MA440 Specifications

Extech MA440
Weight‎9.3 ounces
Jaw Size1.2 inches
Display SizeYes
Voltage600 Volts
Current400 Amps
Highest Safety RatingCAT III
Size9.0 x 3.0 x 1.6 inches
Batteries3 x AAA
Diode TestingYes
Capacitance100 μF
Frequency1 MHz
Resistance40 MΩ
Temperature TestingNo

What Do Users Say About the Extech Clampmeter MA440?

For me, the MA440 from Extech is an adequate clamp meter for the home DIYer and undemanding light contractor. Stripped back, it offers all the basic functions you’d expect in an electrical tester, but doesn’t stand out in a packed marketplace.

Yet, am I being too harsh on this machine? To ensure that my MA440 Extech Clamp Meter review is completely unbiased — I researched the opinions of owners of the unit, to discover their thoughts.

Reassuringly, the testimonials were generally positive and echoed my own feelings. Users of the tool lauded its robust and quality build, welcomed the non-contact voltage feature, and praised the safety-boosting CAT III certification.

However, many guys were somewhat underwhelmed. Frequently criticized were the lack of temperature testing, the inclusion of the standard RMS tech instead of the more accurate TRMS, and the inability to detect DC current.

Sure, these areas are addressed in the other higher-spec 440 series machines — but as numerous owners pointed out — many similarly priced models from competitor manufacturers include these functions.

That said, all users agreed that the MA440 from Extech was a reliable machine that offers durability combined with pleasing precision.

Alternatives to the Extech Multimeter MA 440

If after reading this MA440 review, you’ve decided this clamp meter isn’t ideally suited to your needs — all isn’t lost.

Below, I’ve curated some alternatives that may appeal more to your personal needs and the demands of your projects.

Extech MA445

Should you be a fan of the quality and affordably priced Extech brand, but are concerned that the MA440 lacks sufficient features for your job needs — I have the solution.

While the MA445 hails from the same stable as the MA440, its higher specification means the inclusion of more functions — including temperature testing, DC current detection, and True RMS.

  • Harder on your pocket than the MA440 — but still under $100.
  • Built-in flashlight — not a feature of the MA440.
  • Identical jaw size as the MA440.

AstroAI DT201D

If you’re on a serious budget, but still demand the ultimate in functionality, it’s possible that the Extech MA440 is disappointing. That being the case, check out this machine from AstroAI.

While easier on your wallet than the Extech, the DT201D offers features unavailable on the MA440 — including True RMS and temperature testing to 2000 degrees Fahrenheit.

  • Larger jaw — 1.65 inches opposed to the 1.2 inches of the MA440.
  • CAT III rating — identical to the MA440.
  • Cannot measure DC current — neither can the MA440.


If your jobs demand the ultimate in accuracy, the lack of a low-impedance system in the MA440 could be disappointing. Should this be a concern, I have the answer.

The HT206D from KAIWEETS has this precision boosting technology, permitting you to check for ghost or stray voltages that may mar your circuitry testing results. What’s more, it’s comparable to the MA440 with CAT III certification and 600-volt capabilities.

  • RSimilarly priced to the MA440.
  • Includes auto-ranging, not a feature of the Extech.
  • Unlike the MA440, it boasts an in-built flashlight.


Offering the expected functions of a basic clamp meter, the MA440 from Extech is a reliable and robust machine. Although, it has little to make it stand out in the crowded electrical testing arena.

With fuss-free operation and non-contact voltage detection, it’s a suitable first-time unit for the novice user. The 1.2-inch diameter jaw will cope with most standard cables, while its backlit LCD screen offers welcome illumination in dimly lit areas.

Although the CAT III certification will appeal to trade pros dealing with three-phase systems, the lack of TRMS, DC current detection, and auto-ranging could disappoint experienced contractors.

However, if you want a unit that’s built to last and provides guaranteed accuracy — the affordably priced Extech MA440 clamp meter is worth a look.

Extech Clamp Meter MA440 FAQs

Q: What Is the Extech MA440 Price?

The MA440 from Extech is a DIY-targeted clamp meter with a CAT III certification that’s marketed at an affordable price. To check out the current cost of the Extech MA440.

Q: Where Can I Find the Extech Clamp Meter MA440 Manual User Guide?

The official Extech website includes a library of all the manuals for its current and discontinued electrical testing tools. For rapid access to the Extech MA440 manual.

Be warned that this manual covers all models in the 440 series — so some features included in this user guide do not apply to the MA440 machine.

Q: Where Can I Buy the Clamp Meter Extech MA 440?

The Extech Multi Clamp Meter MA440 is a DIY-focused unit that’s available at a budget price. To get your hands on this basic machine, click here.

Q: What Batteries Does the Extech Multimeter MA440 Use?

The MA 440 from Extech requires 3 x AAA power cells. These are pleasingly included with the unit purchase.

Q: Is Extech a Good Make of Clamp Meter Testing Machines?

Yes! Extech is a US-based company based in Nashua, New Hampshire. It retails and manufactures a multitude of testing machines from its factories in Taiwan, Hong Kong, and Shanghai.

Its history dates back to 1971 and is respected for its high-quality and accurate tools for both home users and trade pros.

Q: Can the Extech Clamping Meter MA440 Model Test Temperature?

No. Temperature testing isn’t a feature of the back-to-basics MA440 model. If you’re looking for a heat investigative unit from the Extech brand, check out the higher-specced yet still affordably priced MA445.

Q: Does the Extech MA 440 Clamp Multi Meter Have TRMS?

No. The MA440 from Extech is a standard RMS clamp meter. If you require the precision of TRMS from your Extech machine, check out the MA445 instead.

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