Klein MM325 Review


Editor Rating: 4.5/5


Klein Tools MM325 Multimeter

Reviewed by: Sean Masri

Last modified: Sep 4, 2023 @ 2:10 am

  • Design
  • Functionality
  • Price

Klein Tools MM325 Review Summary:

Hitting the budget sub-$50 multimeter price point, yet delivering reliability and robustness above its affordable status — the Klein MM325 targets the novice multimeter user and home electrical DIYer.

Able to investigate up to 600 volts of power, it’s more than acceptable for domestic mains wiring and appliances testing. With an effortless turn of the unit’s substantial selector dial — you can choose between continuity, resistance, voltage, current, and diode testing.

Capable of handling drops from 6.6 feet, the MM325 offers reassuring durability. And, with a backlit 2000-count LCD screen, the multimeter provides easy result reading — even in dimly lit locations.

Its low battery warning system ensures that you’re not left with an unusable tester halfway through a project — while a straightforward easy-access fuse compartment allows you to rapidly switch current breakers should they blow.

The Klein MM325 multimeter arrives with testing leads, 2 x AAA batteries, probe head protectors, and a user manual. And, if you want more, Klein also offers a complete testing kit — including the multimeter and above accessories, together with a soft carry case, NCV tester, voltage tester, and receptacle tester.

This tool comes from the Klein Tools stable — a US company known for its reliable and reasonably-priced DIY and trade equipment. The MM325 is the entry-level unit in its extensive multimeter range.


  • Voltage: 600 volts
  • Auto range: No
  • Weight: 0.55 pounds
  • Current: 10A
  • Temperature: No


  • Low-battery indicator.
  • CAT III rating.
  • Kit available with NCV, voltage, and receptacle testers and carry case.


High-quality DIY multimeter.
CAT III safety rating.
Data hold feature.
Battery-saving auto-power off.

Respected manufacturer.


Lacks features for trade use.
Fragile support stand.
Leads often self-detach from rear storage.
No auto-ranging.

Features and Benefits of the Klein Tools MM325 Multimeter

The MM325 multimeter from Klein Tools is an unashamedly back-to-basics unit — but can it still impress in the feature and functionality department? It’s time to discover what this electrical tester can do.

LCD Screen

Generously proportioned, the MM325’s display offers effortless result reading even in poorly illuminated conditions.

Boasting a 2000-count on its large digit backlit screen — it allows for multi-angle viewing and permits operation in dark environments such as beneath floorboards, in attics, and inside cupboards.


Accidents happen — that’s why it’s pleasing to see that the Klein MM325 multimeter is built for robustness.

Capable of withstanding a 6.6-foot drop, the unit delivers reassuring durability — meaning that if you find yourself with slippery perspiring fingers at the top of a step ladder, your hardcore machine can take the fall.

Multifunction Testing

Although a budget machine, the MM325 from Klein offers a plethora of testing capabilities.

Turning the substantial center dial allows you to effortlessly select between:

  • Voltage.
  • Current.
  • Resistance.
  • Diode testing.
  • Continuity.

This enables you to use the multimeter for the most common household projects, such as detecting faults and broken wires, mains power troubleshooting, investigating dead batteries, automotive repair, and fixing Christmas lights.


As long as you follow the manufacturer’s instructions, take the necessary precautions, and follow good practice — using a multimeter is completely safe. And, if you purchase a machine that boasts robust shielding features, your well-being is further protected.

Reassuringly, the MM325 Klein Multimeter takes user safety seriously. It incorporates a heavily insulated case, meets stringent CAT III safety standards, is CE (Europe) and UKCA (UK) certified, and boasts a ceramic internal fuse.

Battery Power and Management

The Klein Multimeter MM325 arrives complete with 2 x AAA batteries — allowing you to crack on with your electrical testing straight after unboxing.

And, to protect these cells from rapid depletion and to ensure you’re not caught out with a dead multimeter halfway through your project — the machine includes two important power-protecting features.

Auto-power off deactivates the multimeter if no buttons are pressed or readings are taken within 15 minutes — saving valuable battery life. Plus, if the power level in your cells becomes seriously low, the unit provides an on-screen warning that indicates it’s time to replace your batteries.

Data Hold

Pressing the substantial HOLD button just below the LCD screen keeps your most current test reading on the display. This permits you to record the result elsewhere, consider your findings, or relay it to a colleague or customer.

And, simply press again to return your multimeter to live testing mode.

Additional Kit Option

The MM325 multimeter is also available with a complete electrical testing kit. In addition to the probes and batteries included with the tool-only option, this Klein set incorporates:

Klein Voltage Tester ET45

Investigates voltages from 28 volts to 240 volts AC, and 32 volts to 330 volts for DC systems.

Klein NCVT-3P Tester

A non-contact voltage detector that allows you to check for live power circuits, without having to touch any wires or components. Its range extends from 12 to 1000 volts.

Klein RT210 GFCI Tester

This GFCI (ground-fault circuit interrupter) tester allows you to check mains sockets for the most common problems — including reverse polarity, open hot, open neutral, open ground, and reversed wiring.

Carrying Case

A generously-sized carry pouch to store and protect the MM325 and all the above accessories.

Klein MM325 Specifications

Klein MM325
Weight0.55 pounds
MaterialABS plastic
Voltage600 volts DC max
Current10 amps
Safety RatingCAT III 600V
Size6.41 x 1.83 x 3.13 inches
Batteries2 x AAA
Batteries IncludedYes
Auto-Power OffYes
Diode TestingYes
Accuracy+/- 2 percent

What Users Say About the Klein MM325

In my opinion, the MM325 Klein Multimeter is a durable machine boasting robust safety features — ideal for the novice or casual DIY electrical testing user.

But, with limited time experience with this unit, it’s tough to give a thorough Klein MM325 review. Therefore, to ensure you receive a warts-and-all exposé of this machine, I sought the views of guys who own this multimeter.

Mostly, the opinions expressed were generally positive and echoed my own. Users welcomed the easy-to-read screen, lauded the 6.6-foot drop durability, and praised its battery-saving features.

However, some owners were a little disappointed.

Numerous users explained that many similarly-priced budget multimeters included more comprehensive testing capabilities — including temperature, frequency, and capacitance. Others pointed out that for the same number of dollars, you can get your hands on a more accurate and easier-to-operate TRMS or auto-ranging unit.

That said, all owners agreed that the MM325 was a solid, reliable, and safe electrical testing machine.

Alternatives to the Klein Tools MM325 Multimeter

If the MM325 Klein multimeter doesn’t meet your electrical testing tastes, or lacks the crucial features you need for your projects — stick with me!

I’ve put together three impressive alternatives below that may be more suited to your personal preferences and electrical job types.

AstroAI Digital Multimeter DM6000AR

If you like the budget pricing combined with the reliability offered by the MM325, but are disappointed it lacks auto-ranging — check out the DM6000AR multimeter.

Hailing from the AstroAI stable, this machine is available for around the same affordable price as the Klein unit, yet features auto-ranging and MAX/MIN memory functions — neither of which are available on the MM325.

  • Includes hanging magnet, not included with the Klein model.
  • Unlike the MM325, the AstroAI can measure temperature.
  • Same CAT III rating as the Klein multimeter.

Extech MN35

Extech mn35

Should the budget pricing of the Klein machine appeal, yet you’re disappointed that it doesn’t come with temperature testing features — consider instead this affordable Extech multimeter.

The MN35 arrives at around the same price point as the MM325, but unlike the Klein machine, includes temperature probes to investigate heat levels up to 1400 degrees Fahrenheit. A usual function if your jobs include HVAC or automotive projects.

  • CAT III rated for 600 volts like the MM325.
  • Data hold feature included, the same as the Klein multimeter.
  • Like the MM325, it has a 2000-count display.

Klein Tools MM720

If you’re impressed with the respected Klein brand, but want a more advanced machine than the MM325 for your hardcore DIY or trade jobs — consider this machine instead.

The MM720, available for under $ 100, is a prosumer/light contractor-focused unit. As such, it boasts premium features not included on the MM325 — such as temperature, low-impedance, TRMS, auto-ranging, and a CAT III rating.

  • Harder on your wallet than the MM325.
  • MIN/MAX feature — not included on the MM325 multimeter.
  • 6000-count display in contrast with the 2000-count of the MM325.


Heavy on safety, durable, and reliable — the MM325 Klein multimeter is a budget-priced electrical tester with a premium-grade build.

Its 2000-count backlit screen offers effortless reading, while 6.6-foot drop-proof resistance delivers reassuring robustness. Impressive power-saving functions ensure the unit doesn’t fail mid-project, and its data hold setting permits fuss-free recording of results.

Sure, the machine lacks the testing capabilities demanded by experienced home users and trade pros. And equally, there are budget-branded alternatives that offer more features.

However, for an affordable multimeter that will stand up to abuse and promise longevity — few units can match the sub-$50 Klein MM325.

Klein Tools MM325 Review FAQs

Where Can I Buy the Klein Tools MM325?

The MM325 is a robust multimeter that delivers a large LCD screen, multifunction testing, power saving, and data hold. Here is the link to buy the tool only, or alternatively, purchase the MM325 kit.

What’s the Difference Between Klein Tools MM325 vs MM600?
The MM325 is an entry-level multimeter for the DIYer and casual user. The MM600 — now discontinued and replaced by the MM720 — boasted more accuracy and testing capabilities than the MM325.

These included auto-ranging, TRMS, and temperature investigation up to 1000 degrees Fahrenheit.

Where Can I Find the Klein Tools MM325 Manual?

The official Klein Tools website hosts user guides for all its multimeters. To save you time searching for it, here is the MM325 Multimeter Manual.

What's the Difference Between the Klein Tools MM325 vs MM400
The MM400 is discontinued, and has been replaced by the MM420. This multimeter is a step above the entry-level MM325 — offering more advanced features, including TRMS, auto-ranging, capacitance testing, and temperature investigation.
Are Klein Tools Made In the USA?
Klein Tools is a US-based company that’s family-owned and run. Their official website states that the majority of its tools are manufactured in the USA — although the Klein MM325 multimeter is made in China.

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