What's inside
- Quick comparison of the best digital multimeters
- Best overall: Fluke 117
- Best premium accuracy: Fluke 87V
- Best budget: Klein Tools MM400
- Best value pro: Klein Tools MM700
- Best starter: AstroAI AM33D
- How to choose a multimeter
- Worked example: choosing by situation
- Ownership realities
- Which multimeter should you buy?
- Frequently Asked Questions
- Quick comparison of the best digital multimeters
- Best overall: Fluke 117
- Best premium accuracy: Fluke 87V
- Best budget: Klein Tools MM400
- Best value pro: Klein Tools MM700
- Best starter: AstroAI AM33D
- How to choose a multimeter
- Worked example: choosing by situation
- Ownership realities
- Which multimeter should you buy?
- Frequently Asked Questions
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The best digital multimeter for most people is the Fluke 117: it is a True RMS, auto-ranging meter rated CAT III 600V with a low-impedance mode that avoids ghost-voltage readings and a built-in non-contact voltage detector. For a lower price, the Klein Tools MM400 is a sound budget choice, and for lab-grade accuracy the Fluke 87V is the long-time industrial standard.
A digital multimeter (DMM) measures voltage, current and resistance, and most also test continuity, diodes and capacitance. The features that decide a purchase are safety category, accuracy, True RMS, auto-ranging and build quality, not the number of buttons.
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Quick comparison of the best digital multimeters
| Pick | Best for | Key specs (per maker) | Price tier |
|---|---|---|---|
| Fluke 117 | Best overall, electricians | True RMS, CAT III 600V, AutoVolt, LoZ mode, built-in non-contact voltage detection | Premium |
| Fluke 87V | Best for industrial and motor work | Around 0.05 percent DC accuracy, up to 1,000V, CAT III 1000V and CAT IV 600V | Premium |
| Klein Tools MM400 | Best budget pro-style meter | Auto-ranging, 600V AC/DC, CAT III 600V | Budget to mid-range |
| Klein Tools MM700 | Best value among pro meters | True RMS, wider function set than the MM400 | Mid-range |
| AstroAI AM33D | Best starter meter | Basic auto-ranging, low cost, home use | Budget |
Specifications come from manufacturers’ published sheets and may change between production runs. Always check the safety rating printed on the meter.
Best overall: Fluke 117
The 117 is built for electricians. It selects AC or DC voltage automatically, reads True RMS so it measures non-sinusoidal signals correctly, and has a LoZ mode that loads the circuit slightly to remove phantom voltage from adjacent wires. A VoltAlert non-contact detector lets you check for live conductors before touching a probe.
Trade-off: it is expensive, it has no CAT IV rating.
Best premium accuracy: Fluke 87V
The 87V is the industrial benchmark. It has high DC accuracy, a peak-capture function for motor starts and a CAT IV rating, and it is made for plant maintenance and motor drive work. It reads up to 1,000V.
Trade-off: it is more meter than most buyers need, and it lacks LoZ and a built-in non-contact detector.
Best budget: Klein Tools MM400
Klein’s MM400 gives most homeowners and apprentices what they need: auto-ranging, 600V AC and DC, continuity and a rugged case. It is CAT III 600V rated and costs much less than Fluke.
Trade-off: it is not True RMS, so readings on variable-speed drives and dimmers can be off.
Best value pro: Klein Tools MM700
Step up to the MM700 if you need True RMS and more features such as temperature and capacitance. It is a common pick for working electricians who do not need Fluke pricing.
Trade-off: long-term durability and calibration support are not at Fluke’s level.
Best starter: AstroAI AM33D
For checking batteries, outlets and household appliances, a basic meter from AstroAI does the job. It is not for panel work.
Trade-off: low safety margin and build quality. Do not use it in industrial or high-energy circuits.
How to choose a multimeter
Safety category
CAT ratings describe where on an electrical system the meter is safe. CAT II covers wall outlets and plug-in loads. CAT III covers distribution panels and branch circuits. CAT IV covers the service entrance. For home electrical work, pick CAT III 600V or better. A meter with no category rating is for electronics only.
True RMS
Average-responding meters read incorrectly on non-sinusoidal waveforms. True RMS meters are accurate on electronic loads, motor drives and LED dimmers. If you work on modern equipment, True RMS is worth the extra cost.
Auto-ranging and counts
Auto-ranging selects the right scale, so you rotate the dial to the function and read the result. A 6,000-count display shows values up to 5,999, which is enough for most work; 20,000-count meters read finer.
Accuracy
Typical DC voltage accuracy ranges from 0.5 percent on budget meters to 0.05 percent on lab-grade models. For household work, 0.5 percent is fine. For electronics and calibration, aim for 0.1 percent or better.
Input impedance and LoZ
Most DMMs have 10 megohm input impedance, which can display ghost voltage on unconnected wires. A low-impedance (LoZ) mode removes this at the cost of loading the circuit. It is useful for electricians checking control wiring.
Worked example: choosing by situation
| Situation | Needed rating | Recommended meter class |
|---|---|---|
| Checking AA batteries and outlets | CAT II 300V or higher | Basic auto-ranging meter |
| Home panel and circuit work | CAT III 600V | Klein MM400, Fluke 117 |
| Variable-speed drives, electronics | True RMS | Fluke 117, Klein MM700 |
| Industrial plant, motors | CAT IV 600V | Fluke 87V |
| Hobby electronics | Good DC accuracy, low-current ranges | Any 6,000-count meter |
Ownership realities
- Replace the test leads when the insulation cracks or the tips wear; poor leads are the most common safety failure.
- The current fuse is the most common repair. Never replace it with a lower-rated or generic fuse; use the type specified in the manual.
- Never measure current by placing the probes across a voltage source; this blows the fuse or worse.
- Check the meter on a known source before and after a safety-critical measurement.
- Store the meter dry and remove the battery when stored for months.
Which multimeter should you buy?
Buy the Fluke 117 if you do electrical work for money. Choose the Klein MM400 if you are a DIYer or apprentice who wants a safe, rugged meter at a lower price. Step up to the Fluke 87V only for industrial or precision requirements. For the odd battery check, an entry meter is fine.
Frequently Asked Questions
What is the best multimeter for home use?
A CAT III 600V auto-ranging meter, such as the Klein MM400, is a good fit. It handles outlets, switches and appliance checks safely.
Is True RMS necessary?
For simple household circuits, not strictly. For dimmers, drives and electronic loads, True RMS gives correct readings.
What does CAT III mean?
CAT III means the meter is rated for distribution-level circuits such as panels and branch circuits, with a defined voltage limit and transient protection.
Is a Fluke worth the price?
For daily professional use, yes. Fluke is known for accuracy, safety testing and long service, and many models carry a long warranty. Occasional users may not need it.
How do I test a battery with a multimeter?
Set the meter to DC volts, touch red to positive and black to negative, and read the display. A fresh AA reads about 1.5V; below about 1.2V it is weak under load.
Can a multimeter measure amps?
Yes, but the meter must be placed in series with the circuit using the current jack. A clamp meter is safer for high currents.