Klein MM300 vs MM400

Klein MM300 vs MM400 – Choosing the Best Fit

When it comes to multimeters, Klein is a brand that’s no stranger to the game. They’ve built a solid reputation for themselves in electrical tools and equipment. 

But let’s focus on the stars of the show: the MM300 and MM400 multimeters. These bad boys are not only reliable, but they also won’t break the bank. Yep, they’re two of the most budget-friendly options out there.

Based on my experience and expertise in this field, let’s delve into what sets these two multimeters apart in this comparison. 

By the end, you’ll have a clear picture of which one suits your needs like a glove. Let’s get this comparison show on the road!

Klein MM300 vs MM400 – Which One to Consider?

In a nutshell, the main difference between the Klein MM300 and MM400 in their ranging capabilities. The MM300 is a manual-ranging multimeter, while the MM400 is an auto-ranging one.

So, here’s my personal take:

If you prefer manual ranging and are looking for a budget-friendly option, go for the Klein MM300.

But if you crave the convenience of auto-ranging and can stretch your budget a bit, the Klein MM400 is the way to go.

If you value manual-ranging control and are on a tight budget, the MM300 is a reliable choice with essential measurement capabilities.

But if you crave the convenience of auto-ranging and can stretch your budget a bit, the Klein MM400 is the way to go.

Klein MM300 vs MM400 – Specifications

FeatureKlein MM300Klein MM400
Display2000-count LCD4000-count LCD
True RMSNoNo
Voltage Range0.1mV – 600V0.1mV – 600V
Current Range0.1μA – 10A0.1μA – 10A
Resistance Range0.1Ω – 20MΩ0.1Ω – 40MΩ
Capacitance Range1nF – 200μF
Frequency Range1Hz – 50 KHz
Duty CycleYes
Temperature Range0°F to 1000°F(-18° – 538°C)
Diode TestYesYes
Continuity TestYesYes
Low Battery IndicationYesYes
Safety RatingsCAT III 600VCAT III 600V
Drop Protection3.3 ft (1m)3.3 ft (1m)

Klein MM300 – Quick Rundown


  • Measures up to 600V AC/DC voltage
  • CAT III 600V safety rating
  • Low battery indicator
  • Voltage tester
  • Built to withstand a 3.3-foot (1m) drop
  • Suitable for daily wear and tear

Alright, let’s jump right into the Klein MM300! I’ve had the pleasure of using this bad boy before, and I’m here to give you the lowdown.

This little guy is a manual-ranging multimeter, so you’ll need to set the appropriate range for each measurement manually. Now, some folks prefer the control that comes with manual ranging, so if that’s your jam, keep on reading!

The MM300 is a versatile tool that can handle a range of measurements. It’s got your back regarding AC/DC voltage, DC, resistance, batteries, diodes, and continuity. So whether you’re tinkering with electronics or troubleshooting electrical circuits, this multimeter has covered you.

One thing to note is that the MM300 lacks a few features compared to its sibling, the MM400. It doesn’t have auto-range. Additionally, it doesn’t offer temperature, duty cycle, or capacitance measurements. If those features are essential for your needs, consider the MM400 instead.

Oh, and let’s not forget the audible continuity tester, making it a breeze to check for open or short circuits.

Overall, the Klein MM300 is a trusty companion for hobbyists and DIY enthusiasts who need a versatile tool for various applications.

The package for the Klein MM300 includes:

  • Klein MM300 multimeter
  • User manual
  • Test leads
  • Batteries


  • Competent and well-built construction
  • Budget-friendly option
  • Low battery indicator
  • Audible continuity tester


  • Slow response
  • Limited battery life
  • Lacks features like auto-range, temperature measurement, duty cycle measurement, and capacitance measurement

Klein MM400 – Quick Rundown


  • Measures up to 600V AC/DC voltage
  • Electrical tester: temperature, capacitance, frequency, duty-cycle
  • CAT III 600V safety rating
  • Withstands a 3.3-foot (1 m) drop
  • Low battery indicator
  • Suitable for light-industrial locations

Read Klein MM400 Multimeter Review

The MM400 is a step up from its sibling, the MM300, and it brings some notable improvements to the table. Klein has taken user feedback and made some enhancements to address previous concerns and provide an even better experience. 

Unlike its sibling, the MM300, the MM400 is an auto-ranging multimeter.

Now, one thing to note is that the MM400 doesn’t have True RMS (Root Mean Square) measurement capability. If you’re not familiar with it, True RMS allows for more accurate readings when dealing with non-sinusoidal waveforms. However, if you’re not working with complex waveforms, it shouldn’t be a deal-breaker.

However, don’t let that overshadow the MM400’s impressive capabilities. It offers AC/DC voltage, DC current, resistance, batteries, diodes, continuity, and even frequency measurement. 

Additionally, the MM400 has a duty cycle measurement feature, which comes in handy when dealing with devices that utilize pulse-width modulation (PWM) signals. It allows you to determine the percentage of time a signal is on versus off, giving you insights into the performance of your equipment.

Klein has continued to evolve their multimeter lineup with newer models like the MM1000 or MM6000, which do offer True RMS measurement capability. So, if you require that level of accuracy, you might want to explore those options.

But for those seeking an upgrade from the MM300 and don’t necessarily need True RMS, the MM400 is a solid choice. With added temperature measurement and duty cycle functionality, it offers expanded capabilities to help you tackle a wider range of projects. 

The package for the Klein MM400 includes:

  • Klein MM400 multimeter
  • Thermocouple with adapter
  • User manual
  • Test leads
  • Batteries


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


  • Not True RMS

What Users Say About Klein MM300 and MM400

When it comes to customer reviews, they hold immense importance in helping us make informed decisions. So, let’s dive into what users have to say about the Fluke 101 and the Klein MM400.

Starting with the Klein MM300, users commend its competence and robust construction, all while being gentle on the wallet. However, there are a few limitations to note.

Some users mention a slower response when it comes to continuity checks and limited battery life due to the use of AAA cells instead of AA cells.

But overall, many recommend the MM300 for beginners in electronics projects or handy do-it-yourself enthusiasts who seek a basic, reliable, and reasonably priced multimeter that adheres to safety codes and regulations.

Now, let’s shift gears to the Klein MM400. Users rave about its versatility, whether used for automotive work or household electrical tasks. It’s often considered a significant upgrade from the meters you find at local discount tool stores.

Users appreciate the clear and crisp readout, the effective backlight, and the supple lead wires that fit snugly into household outlets. The inclusion of a long-reaching K-type thermocouple that provides accurate temperature readings within 1 degree Fahrenheit is also praised.

The MM400’s continuity test, equipped with a light and beeper, proves handy in environments requiring hearing protection. Users also highlight the grippy and durable rubber case, along with the convenient stand that keeps the meter at a good viewing position on semi-level surfaces.

Lastly, the MM400 is celebrated for its feature-packed nature, offering AC/DC current, frequency, duty cycle, thermocouple temperature, capacitance, and diode testing. While it may not perform as flawlessly as a pricier $200 meter, it certainly gets the job done.

So, based on user experiences, it seems the Klein MM400 garners more positive feedback, with its versatile features, excellent build quality, and overall reliability. However, it’s important to consider your specific needs and budget before making a decision.

Final Verdict – MM300 vs MM400

In the final verdict of the MM300 vs MM400 face-off, it ultimately boils down to your specific needs and preferences.

If you’re comfortable with manual ranging and seek a budget-friendly option, the MM300 is a reliable choice for beginners or DIY enthusiasts. However, if you value the convenience of auto-ranging and are willing to invest a bit more, the MM400 offers versatility and improved user experience.


We write everything about coffee and espresso machines for a few years. Our goal is to provide you with helpful content that you can trust based on our own personal experiences, information from manufacturers, and tips and tricks shared by coffee and espresso machine users online.

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