Are electrical issues causing you a headache? Sort them out with a great multimeter.
Craig ColeFormer reviews editor
Craig brought 15 years of automotive journalism experience to the Cars team. A lifelong resident of Michigan, he's as happy with a wrench or welding gun in hand as he is in front of the camera or behind a keyboard. When not hosting videos or cranking out features and reviews, he's probably out in the garage working on one of his project cars. He's fully restored a 1936 Ford V8 sedan and then turned to resurrecting another flathead-powered relic, a '51 Ford Crestliner. Craig has been a proud member of the Automotive Press Association (APA) and the Midwest Automotive Media Association (MAMA).
While it's often best to call an electrician if you suspect you have a dangerous electrical issue, you can also safely diagnose many of those problems yourself with a multimeter, which is why it's important to have a multimeter in your home. Once you've diagnosed the problem, you'll already be on your way to fixing it. After all, knowing is half of the battle.
Multimeters measure a variety of things, including continuity, current, resistance and voltage (though some measure a whole lot more). Because of their flexibility, these tools are incredibly versatile, but they're also intimidating. Seriously, what setting do you use to test a spark plug wire? Which ports do the probes attach to? How do I measure alternating current voltage? Fortunately, with a little background information, multimeters are pretty straightforward tools that are surprisingly easy to use.
In this article, we'll answer those questions (and more) and explain pretty much everything you need to know about multimeters. We've also aggregated a few recommendations, multimeters you should consider purchasing if you want to fix your own electrical issues rather than paying someone else to do it. The products highlighted here are based on real-world experience and user reviews, so you know they're good. Multimeters are a great addition to any garage or tool box. If you don't already have one, hopefully you'll be convinced to pick one up after reading this article.
The Klein Tools MM400 multimeter offers a great blend of features at an attractive price. This tool can measure resistance as well as AC voltage and DC voltage power at a maximum of 600 volts and up to 10 amps. Beyond the basics, the MM400 can also measure temperature, capacitance and frequency. For added convenience, this multimeter features automatic ranging (more on that down below) and comes with test leads and a thermocouple with the required adapter. A low-battery indicator and an easily accessible battery compartment for quick changes are included, too. If you're curious, this digital multimeter runs on a pair of AA batteries, which are cheap and readily available. Built to last, the Klein Tools MM400 multimeter is designed to withstand drops from a height of 3.3 feet (1 meter). This tool does a lot and yet it costs a totally reasonable $50. The MM400 is also highly regarded, one of the best multimeters you can buy. Customers have given this Klein Tools product a rating of 4.7 stars, which is excellent.
For electrical hobbyists, tinkerers and shade-tree mechanics alike, the AstroAI AM33D is hard to beat. In fact, it's our pick for the best general-purpose multimeter. This no-nonsense unit can measure AC and DC voltage, DC current, electrical resistance and even has a continuity meter. The backlit digital display is crisp and it comes with a data-hold function as well as a battery meter so you know when it's time to replace the included 9-volt battery. This isn't the fanciest multimeter on our list here, but it's still a damn good product, especially for the price. You can grab one of these units for a paltry $13, which is a steal. Not only is this tool super affordable, it's adored by customers. Currently, the AstroAI AM33D digital multimeter has a 4.5-star rating after more than 33,200 customer reviews… 33,200.
The Milwaukee 2216-20 is our pick as the best professional-grade multimeter. Aside from being offered by a top-tier tool brand, this measuring device looks great and offers loads of features. This Milwaukee multimeter features a digital and backlit LCD display that is easy to read, it has automatic ranging down to millivolts, something explained down below, and this multimeter works at up to 600 volts for either AC or DC voltage. Aside from ohms and continuity, it can also measure capacitance and frequency. Throw in an ergonomic design as well as a sturdy construction and this tool is a top choice for professional electricians. At about $170, this multimeter is definitely pricey, but customers love it. The Milwaukee 2216-20 digital multimeter currently has a stellar 4.8-star ratio out of a possible 5.
Of course, if $150 is too rich for your blood, you can save a few buckaroos on this unit. The White Deer DT-830B is our favorite bargain-basement digital multimeter. It does nearly everything you could need and costs less than $8. It features a 0.5-inch-high, seven-segment LCD, has a compact design, comes with overload protection on all ranges and can sample two to three times per second. Of course, this multimeter offers accurate measurement of all the common things like resistance, current draw and volts for both AC and DC current. If you don't have a lot to spend or just want to keep a spare multimeter in your trunk, recreational vehicle or travel tool box, this best cheap multimeter pick is an obvious thing to purchase.
If you need a multimeter and don't have a lot of space, consider purchasing the MMB-8332R by Commercial Electric, our choice for the best pocketable multimeter. Like larger units on our best multimeter list, this one measures current, voltage (up to 600), resistance, capacitance and even frequency. It features automatic ranging and comes with a backlit display. Making it easy to drop into your pocket, this digital multimeter's dimensions are impressively petite, as it's less than 5 inches tall, 2.5 inches wide and 1.5 inches thick. The test leads are integral to the design, so you never have to worry about losing them, this tool comes with two AAA batteries and even a Velcro storage strap. For on-the-go convenience, it's hard to top the Commercial Electric MMB-8332R multimeter, which is priced to sell at just $51.
So far, all the multimeters highlighted on this best multimeter list have been of the digital persuasion. If you're old school and prefer an analog indicator, this is the multimeter for you. The Gardner Bender GMT-318 costs just $19, yet it does practically everything you could ever need, and it looks great with its traditional readout, which features a sweeping indicator needle on a color-coded display. This tool features a 15-position rotary dial and can measure AC current and DC current, DC amps, resistance and transistor gain. It comes with fused overload protection and even a spare fuse should you inadvertently get a little carried away. As for downsides, this multimeter does feature manual range selection, which some users may not prefer, plus analog multimeters can be harder to read than their digital counterparts and they're probably more fragile, but this is still a quality unit that's super affordable. Customers like this device, too. Some 90% of them recommend it, and they've given it a rating of 4.3 stars out 5.
Working professional electricians are sure to love this Fluke multimeter. The Fluke 117 is ready, willing and able to work overtime diagnosing electrical issues and testing circuits. The Fluke meter offers measurement capability for resistance, continuity, frequency, capacitance and more. Naturally, it works with both AC and DC current and has a maximum resolution of 1 milliamp. It can even detect either one of those currents automatically. Protecting the user, this tool comes with integrated, non-contact voltage detection so you know whether a circuit is hot, an awesome safety feature. With a backlit display and a well-thought-out interface, this digital multimeter should also be a pleasure to use.
With an included test lead set, the Fluke 117 multimeter costs nearly $300, which isn't cheap, but this tool is loaded with features and should last for many years, even under difficult conditions. Burnishing this multimeter's professional-grade bona fides, it has a stellar 4.8-star rating after more than 200 real-world customer reviews. And if that doesn't sell you on this best multimeter pick, nothing will.
Among many other features, the Cen-Tech 98674 digital multimeter comes with an integrated kickstand, which makes it easier to read the screen, particularly while working in tight places. That's why this tool is our pick as the best multimeter for mechanics. Like the other units highlighted here, this automotive multimeter can test voltage, current, frequency, capacitance and resistance, but that's not all. It can also measure sound and humidity levels, temperature and even luminosity, 14 functions in total. Talk about a full-featured device. This Cen-Tech multimeter has a large, 3.75-inch LCD that should be a snap to read, it comes with substantial, 24-inch-long leads and features a soft over-molded cover for a comfortable grip. Automatic ranging is another feather in its cap.
At $80, this device isn't cheap, but neither is it outrageous for all the features it comes with. Really, the only downside here is that this best automotive multimeter pick requires three AAA batteries, which are not included. Customers appreciate this tool's features and fair pricing. A claimed 95% of buyers recommend it and this multimeter has a 4.6-star rating further solidifying its spot among the best multimeters available.
Automatic ranging; can measure temperature, capacitance and frequency; highly rated
Best multimeter overall runner-up
AstroAI Digital Multimeter AM33D
Affordable price, features a battery meter and data-hold function, highly rated
Best professional-grade multimeter
Milwaukee Digital Multimeter 2216-20
Professional quality, easy-to-read backlit LCD screen, automatic ranging, rugged construction, very highly rated
Best bargain-basement multimeter
White Deer Multimeter DT-830B
Ultra-low price, LCD screen, compact design
Best pocketable multimeter
Commercial Electric Pocket Size Auto Ranging Multimeter MMB-8332R
Super-compact design, can also measure capacitance and frequency, integral electrical leads
Best analog multimeter
Gardener Bender 14-Range Analog Meter GMT-318
Analog readout, affordable price, includes spare fuse, highly rated
Best money-is-no-object multimeter
Fluke 117 Electricians True RMS Multimeter
Professional quality; measures resistance, continuity, frequency, capacitance and more; integrated, non-contact voltage meter; easy-to-use design; very highly rated
Best all-around multimeter for auto mechanics
Cen-Tech Digital Multimeter 98674
Integrated kickstand; measures current, frequency, capacitance, resistance, sound, humidity, temperature and luminosity; automatic ranging; highly rated
Multimeters measure a variety of things, chiefly current, continuity, resistance and voltage. Each of these facets of electricity are distinct, and knowing what they do and how they function can help you diagnose and ultimately correct issues.
Electrical current draw is measured in amps, or amperes if you're feeling pedantic. To ascertain the power an electrical device or a circuit is pulling, you have to open it up, either by cutting a wire or unplugging part of the circuit. This is necessary because you need to hook the multimeter up in series, so power flows into one of the device's leads and out the other. This is how multimeters measure the amps being drawn by, say, a light bulb, electric motor or resistive heater.
Multimeters also measure continuity, meaning, they can check to see if a circuit is open, that is, whether there's a break in the wiring or if the connection between two points is good. A multimeter's continuity mode is typically indicated by a sound wave symbol. In this mode, when the probes are attached to both ends of a circuit that isn't broken, an audible tone will be emitted by the device. This is helpful because you can tell if the circuit is good without looking at the screen, which enables you to concentrate on holding the probes as still as possible and where they need to be. With a circuit that is broken, say, when a switch is turned off or a wire has been cut, no tone will be emitted.
The continuity setting on a multimeter can also measure poor conductivity in a circuit. If the contacts of a switch, for instance, are dirty, electricity may still flow through it, though at a reduced rate. In cases like this, the multimeter may not buzz, but it will display the electrical resistance present in the switch, a helpful diagnostic point.
Electrical resistance is the next major thing multimeters can measure. Resistance is quantified in ohms, which are indicated by this horseshoe-like symbol, Ω, the Greek letter omega. All conductors, whether it's water, your body or a strand of copper wire also resist the flow of electricity to some degree. Being able to measure resistance is particularly handy when checking spark plug wires, ignition coils or myriad other automotive components. You can also check for an open or broken circuit by measuring resistance. If there's zero resistance the circuit could be damaged.
Next, multimeters can also be used to check voltage, either in direct- or alternating-current circuits. Most automotive electrical components run on DC voltage, and typically on 12 volts, though the power in your home, office or garage is AC. On a multimeter, voltage settings are typically indicated by the letter V, with DC being indicated by the letters DC or a symbol consisting of a straight line over a dotted line. AC is denoted by AC lettering or a small wavy line.
Aside from current, continuity, resistance and voltage, some multimeters can measure electrical capacitance, decibels and even temperature, but that stuff is a bit beyond the scope of this article.
How to use a multimeter
When measuring things with a multimeter, it's important to make sure you have the electrical leads plugged into the correct ports. As applicable, the black one should always go into the socket labeled "com." Depending on the unit, the red lead then plugs into different ports depending on what you're measuring. Read the device carefully and follow manufacturer instructions to avoid mixing things up and potentially damaging your multimeter.
Speaking of damage, some multimeters are fused, so if you hook them to too strong a power source, the fuse burns out, protecting the device's delicate innards. These fuses should be easy to replace by removing the back cover.
You have to be careful where you hook the leads to the multimeter itself, but there are no real concerns about connecting those wires backward when you're testing an electrical device. If you're measuring voltage, for instance, and you touch the positive probe to the negative wire and vice versa, you'll still get a perfectly accurate reading, it will just have a negative in front of it. So, the 115 volts the wall outlet in your office has would simply read -115. This feature is actually handy for determining a circuit's polarity, that is, which side is positive and which is negative.
Most multimeters have a convenient rotary dial for selecting the setting you want, but some have many more settings than others. At first glance, ranging is a confusing topic, but it's not hard to get a grasp of. If you're measuring the resistance of an ignition coil's secondary winding, and it's supposed to clock in at, say, 8,000 ohms, you'd want to set the multimeter to the number one step higher than that. Depending on the model, that would be something like 10,000. Doing this basically moves the decimal point on the screen, but selecting the right setting gives you the most accurate reading possible. Newer multimeters tend to have automatic ranging, which is quite handy. This means you just set the selector dial to ohms (or volts, or amps, or whatever) and the tool decides how to show the number, a convenient innovation.
Finally, a word about safety. The paragraphs above cover the basics of what multimeters do and how you operate them. These tools certainly can be confusing, but once you break everything down, they're not that difficult to understand. But before you start fiddling with electricity, make sure you're safe. Don't touch any exposed wires with your bare hands, wear protective equipment as necessary, make sure you stay within the tool's intended operating range and double-check that the multimeter is in good working order before using it. Finally, always assume every electrical component is hot so you don't get shocked, which can cause severe injuries… or worse.
Make sure a multimeter is part of your toolbox arsenal
The enigmatic multimeter is a super-versatile tool, one that every tinkerer and shade-tree mechanic should have in his or her garage. Multimeters allow you measure volts as well as electrical resistance, current and the continuity of circuits, though higher-end examples can do even more. In fact, one tool included in this rundown can measure 14 different things. Fourteen! If you're new to multimeters, consider getting one with automatic ranging and a digital readout. These examples will be the most intuitive. But no matter the multimeter you go for, they're all indispensable tools for diagnosing and ultimately correcting electrical issues, whether they're in your car, home or favorite gadgets.
What is a multimeter used for?
Multimeters are used a wide range of things, from testing electrical components to make sure they're up to snuff, to diagnosing related problems, but that's not all. Aside from measuring current, continuity, resistance and voltage, fancier models can also detect things like frequency, capacitance, sound, humidity, temperature and even luminosity. Truly, these tools are super versatile.
What multimeter is best for beginners?
No multimeter is really best for beginners. Even the most basic examples are fairly complicated tools, at least at first glance. The good news is, however, it's not hard to understand how multimeters work and what they're used for. With a little study, their functionality is easy to grasp. Even if you just understand the basics of how circuits work, plus what voltage, amps and ohms are, you should be able to use a multimeter for simple diagnostic- and repair-related tasks. If there is one feature beginners should look out for, though, it's automatic ranging, which eliminates the need to put the multimeter in the right setting to display information correctly.
Which brand multimeter is best?
Plenty of companies make good multimeters, but if you want one of the best, stick with well-known companies. Firms like Fluke and Klein Tools have excellent offerings, as does Milwaukee, which is a world-renowned brand that sells everything from wrenches to cordless drills to tool chests.
Is an analog or digital multimeter more accurate?
Digital multimeters are probably more accurate than their analog counterparts because they give you an exact number on their displays. Analog models are undeniably cool, with their old-school aesthetic, but their physical pointer needles can make them harder to read, especially in low-light situations or if there's glare. This is not to say analog units are inaccurate, it's just for most users, digital is probably the better choice.
What is the difference between a multimeter and ohmmeter?
Multimeters and ohmmeters are the same... but different! As their name suggests, ohmmeters are designed to measure ohms, the unit of electrical resistance. On the other hand, multimeters can measure a whole bunch of other things, including, you guessed it, ohms. Unless you have some super specific application where you need an ohmmeter, get a multimeter instead as they measure the same thing yet are far more versatile.
What happens if the multimeter is turned to the wrong setting?
The answer to this question varies. If you have the electrical leads switched around, the tool may simply read -120 volts instead of 120, which is not an issue at all. If you're trying to measure current draw and you have the multimeter set to track ohms, it's probably not going to give you any useful information. Finally, if you're trying to measure more amps than the tool is designed to handle, you could blow an internal fuse (that's what's supposed to happen, to protect the multimeter) or even damage the multimeter. As always, be careful out there.