Klein MM400 vs MM600 – Choosing the Best Fit


As an electrical engineer from Stanford University with over 7 years of experience using multimeters.

To a riveting showdown between two behemoths of the electrical testing world: the Klein MM400 vs MM600. These multimeters are both part of Klein’s starting range and at first glance, they may seem quite similar. However, as an enthusiast who has thoroughly researched these devices, I can assure you that there are important factors that set them apart.

Not only do they have slight price differences, but they also come with distinct features that cater to different needs.

Let’s jump right in!

Klein MM400 vs MM600 – Which One to Consider?

When choosing between the Klein MM400 and MM600, the decision ultimately boils down to your specific needs and budget. While both multimeters offer commendable features, there is a standout contender that might just be the perfect fit for you.

In my opinion, the Klein MM600 shines as an exceptional multimeter that lives up to its promises. It delivers outstanding performance and durability, making it a reliable choice for various tasks. If you’re in the market for a multimeter priced under $100, the MM600 should be at the top of your list.

However, this doesn’t mean we should overlook the MM400 entirely. It remains a more budget-friendly option that still offers reliable performance and a solid feature set. While it may trail behind the MM600 by a small margin, the MM400 provides excellent value for the price.

Klein MM400 vs MM600 – Specifications

FeatureKlein MM400Klein MM600
Display4000-count LCD4000-count LCD
True RMSNoNo
Voltage Range0.1mV – 600V0.1mV – 1000V
Current Range0.1μA – 10A0.1μA – 10A
Resistance Range0.1Ω – 40MΩ0.1Ω – 40MΩ
Capacitance Range1nF – 200μF1nF – 1000μF
Frequency Range1Hz – 50 KHz1Hz – 500 KHz
Duty CycleYesYes
Temperature Range0°F to 1000°F(-18° – 538°C)0°F to 1000°F(-18° – 538°C)
Diode TestYesYes
Continuity TestYesYes
Low Battery IndicationYesYes
Safety RatingsCAT III 600VCAT IV 600V / CAT III 1000V
Drop Protection3.3 ft (1m)6.6 ft (2m)

Klein MM400 – Quick Rundown


  • Measures up to 600V AC/DC
  • Resistance measures 40MOhms
  • 10A AC/DC Current measures
  • CAT III 600V
  • Durability 3.3-foot drop
  • Low battery indicator
  • Measures temperature, capacitance, frequency, duty-cycle, Tests diodes and continuity.

Read Klein MM400 Multimeter Review

Let’s dive into the world of the Klein MM400, a multimeter designed by electricians for electricians. True to its origins, this meter boasts a logical and user-friendly interface, ensuring a hassle-free experience. With its versatile range of test criteria, including capacitance and temperature measurements, the MM400 proves to be a reliable companion across various fields.

While the capacitance range may not reach sky-high levels, capping at 200µF, the voltage and current capabilities are commendable. You can expect accurate readings and solid performance in these areas. The power source for the MM400 comes in the form of readily available AAA batteries, a cost-effective alternative to pricier 9-volt options.

The display on the MM400 is standard, offering a count of up to 4000, and although it lacks a bar graph, it compensates with a convenient backlight feature. The meter’s continuity function includes an audible beeper, promptly alerting you to seamless connections. Furthermore, the MM400’s auto-ranging capability ensures effortless operation.

When it comes to temperature measurements, the MM400 provides flexibility by displaying readings in both Fahrenheit and Celsius. This is achieved through the use of a thermocouple, which conveniently plugs into the main terminal or common connection.

Apart from the slightly restricted capacitance and frequency ranges, the Klein MM400 boasts an array of positive features. It offers test ranges that aren’t always found in multimeters within its price range, making it a solid option for various applications. Keep in mind, however, that a carry case is not included, but can be purchased separately at minimal cost.

While the MM400 may not possess the robustness of its higher-tier counterparts like the MM600 or MM700, it offers great value for its price point. It excels at checking power in socket outlets, switches, batteries, and more, making it a trusted choice for electricians and DIY enthusiasts alike.

The package for the Klein MM400 includes:

  • Test leads
  • Thermocouple with adapter
  • Batteries
  • User manual


  • Trusted brand known for quality
  • Compact and user-friendly design
  • Clear display with convenient backlight
  • Auto-ranging feature and micro-amp capability
  • Includes capacitance, frequency, and temperature inputs
  • Supple leads for ease of use
  • Comes with a thermocouple for temperature measurements
  • Affordable price point


  • Not True RMS (may not be crucial unless measuring variable AC drives)
  • No case included

Klein MM600 – Quick Rundown


  • Measures up to 1000V AC/DC
  • Resistance measures 40MOhms
  • 10A AC/DC Current measures
  • CAT IV 600V / CAT III 1000V
  • Durability 6.6-foot drop
  • Low battery indicator
  • Measures temperature, capacitance, frequency, duty-cycle, Tests diodes and continuity.

Read Klein MM600 Multimeter Review

Behold the self-proclaimed “Tough Meter” – the Klein MM600 lives up to its name, boasting a sturdy construction and sleek design. This multimeter is not only built to last but also designed for ease of use, making it a reliable tool for diagnosing a wide range of issues. Surprisingly, despite its high-quality build, the MM600 falls into the more affordable range among Klein Tools’ multimeters.

The MM600 features auto-ranging, a common feature found in many modern meters, allowing for precise signal detection. Additionally, the Range button enables manual range selection, providing a hands-on approach for faster results. While auto-ranging proves to be a time-saver, like other multimeters in its price range, it may take a moment to settle on the appropriate range.

All amperage scales are accounted for on the MM600, including milliamps and micro-amps, each with their dedicated dial positions. The Select button conveniently switches between AC and DC modes, and separate inputs are available for both high and low amps.

In addition to voltage, current, resistance, diode testing, capacitance, frequency, and continuity measurements, the MM600 also offers temperature functionality. With the ability to display readings in both Fahrenheit and Celsius, simply toggle between the two using the Select button.

This versatile multimeter proves to be a handy troubleshooting device, capable of handling various domestic chores with ease. From testing socket outlets, batteries, and light switches to automotive circuitry, solar-powered battery banks, motors, and circuit board components, the MM600 rises to the occasion, even in demanding field environments.

The package for the Klein MM600 includes:

  • Carrying pouch
  • Test leads
  • Alligator clips
  • Thermocouple with adapter
  • Batteries


  • Reputable brand name
  • Sturdy and durable construction
  • Comprehensive amperage inputs, including milliamps and micro-amps
  • Temperature measurement capability
  • Includes crocodile clips and thermocouple
  • Backlit screen for enhanced visibility


  • Not True RMS (may not be essential for all applications)
  • Continuity function could be faster

What Users Say About Klein MM400 and MM600

Regarding the MM400, users have generally praised its performance, with only a few minor drawbacks worth mentioning. One notable aspect is the absence of True RMS accuracy, which is more commonly found in higher-priced multimeters.

While this may not be a deal-breaker for many, it is noticeable when compared to other models. Additionally, some users have reported that the displayed numbers lose contrast under certain angles, affecting visibility. The brightness of the backlight exacerbates this issue.

However, these concerns don’t overshadow the overall positive feedback received for the MM400.

On the other hand, the MM600 garnered an overwhelmingly positive response from users. Approximately 95 percent of feedback was positive, with most users expressing satisfaction with their purchase.

Users particularly lauded the high-quality build of the meter and appreciated the included accessories, such as the alligator clamp attachments. However, a few users did find the MM600 to be less user-friendly compared to other options on the market, and some even made unfavorable comparisons to the Fluke brand.

Both the MM400 and MM600 have garnered favorable reviews from users, with the MM600 receiving more widespread acclaim. These user experiences provide valuable insights for potential buyers looking to make an informed decision about which multimeter best suits their needs.

Final Verdict

After a thorough examination of the Klein MM400 vs MM600, it’s time to determine the winner. While both multimeters have their strengths and weaknesses, one emerges as the clear victor in this battle.

The Klein MM600 takes the crown for its impressive performance and overwhelmingly positive user feedback. With its sturdy build, comprehensive amperage inputs, temperature measurement capability.

Although the MM400 also has its merits, such as being a solid option for various applications and its affordability, it falls slightly short when compared to the MM600.

Therefore, if you’re seeking a robust and dependable multimeter that delivers consistent results, the Klein MM600 stands out as the clear winner in this comparison. So, equip yourself with the MM600 and embark on your electrical testing endeavors with confidence and precision.

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