Fluke vs Klein Multimeters: MM420, 117 and 87V MAX by Job

Choose the Klein MM420 for home checks and hobby electronics when you want True RMS, temperature and small-current ranges in one meter. Choose the Fluke 117 for electrical troubleshooting when LoZ and built-in non-contact detection matter; choose the Fluke 87V MAX for its industrial functions, tighter DC-voltage specification and rugged enclosure. The Fluke 107 is the pocket alternative when you can accept non-True-RMS AC measurement.

Quick picks: choose the work before the brand

These are recommendations from documented capabilities, not physical testing. For choices across other brands, start with our best multimeters guide.

Fluke vs Klein comparison table

The MM420 manual, 117 manual, 87V MAX manual and 107 manual are the basis for this table. “Not listed” means the model's own function list does not document it.

Best for home and hobby electronics: Klein MM420

The MM420 is our default for someone who wants household basics plus low-voltage component work. It combines auto-ranging and True RMS with capacitance, frequency, duty cycle, continuity and diode testing. Lead-Alert LEDs indicate the input jacks for the selected function.

Its dedicated microamp and milliamp ranges are the reason to choose it over the 117 for small-current work. Its limitations are equally useful buying information: Klein lists neither LoZ nor built-in non-contact voltage detection. The standard package includes leads with CAT III/CAT IV safety caps, a thermocouple and batteries; the meter itself remains CAT III 600V.

The temperature input covers −40 to 1000 °C, but the included thermocouple is suitable only below 180 °C. Buy an appropriately rated probe for hotter measurements. Also, “10 A” is not an unlimited-duration promise: Klein recommends 30 seconds followed by 10 minutes of recovery above 6 A.

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Best for electrical troubleshooting: Fluke 117

The 117 earns its place through VoltAlert non-contact detection, AutoVolt automatic AC/DC selection and LoZ. Its manual specifies approximately 3 kΩ input impedance in AutoVolt to reduce ghost-voltage readings. That is a concrete function advantage over the MM420 for this kind of troubleshooting.

The trade-off is small-current work: the 6 A range resolves 1 mA, without dedicated mA or µA ranges. It is not our first choice for low-current electronics. Fluke's page also contains temperature figures in comparison and footnote material, while the 117's own specification table and manual list no temperature function. Treat temperature as unsupported.

VoltAlert is a detection aid: the manual warns that voltage can still be present without an indication, and not to rely on it with shielded wire. The standard package lists silicone leads and a holster; check the supplied leads' markings rather than assuming a model number from a bundle photograph.

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Best for demanding industrial work: Fluke 87V MAX

Choose the 87V MAX when you actually need its combination of CAT IV 600V / CAT III 1000V, IP67, and a 4 m drop rating with the holster. Its low-pass filter is intended for variable-frequency motor-drive measurements. A low-pass filter is a different function from the 117's low-impedance voltage mode.

It also fits more demanding electronics work: dedicated microamp ranges, temperature and ±(0.05% + 1 count) DC-voltage accuracy on the 6 V through 1000 V ranges. The 600 mV range has a different specification, ±(0.1% + 1). Do not apply the headline accuracy to every range.

The standard box contains TL175 TwistGuard leads, AC175 clips, an 80BK-A temperature probe, a holster and batteries. The included probe covers −40 to 260 °C, less than the meter's −200 to 1090 °C input range. Its 698.5 g with holster is another reason to prefer a smaller meter when those capabilities are unnecessary.

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Best pocket option: Fluke 107

The US-listed 107 weighs 200 g and includes TL75 leads and a magnetic SmartStrap. It measures AC/DC voltage and current, capacitance, frequency and duty cycle, with a backlight.

Fluke explicitly says it is not True RMS. Its True RMS explanation describes why distorted AC from nonlinear loads calls for a True RMS instrument. Choose MM420 or 117 for that requirement. The 107's 4 A lowest current range also makes it a poor substitute for dedicated microamp ranges.

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Accuracy at the same reading: include the counts

For an illustrative 12 V DC display value, use each meter's applicable range and 0.01 V resolution below. Accuracy means ±(percentage of reading + counts × resolution). These are calculations from the linked manufacturer tables, not readings taken by thisMETER; use normal DC volts, with the MAX in standard display mode. The 117's AutoVolt/LoZ mode has a separate accuracy specification.

For example, the MM420 allowance is 60 mV from the percentage plus 50 mV from the counts; the 117 has the same percentage allowance plus 20 mV. Comparing only “0.5%” conceals that difference.

• Klein MM420110mV
• Fluke 11780mV
• Fluke 87V MAX16mV

Source: Calculation from the manufacturer accuracy tables linked above; standard display mode.

Conditions matter: Klein specifies accuracy at 18–28 °C and for one year; the 117 manual also specifies one year after calibration at 18–28 °C. The MAX manual specifies two years at 18–28 °C and changes the count term in high-resolution mode. Resolution alone does not establish accuracy. See How we measure for our approach.

CAT ratings: include the leads and their caps

Fluke's safety guide puts feeders and short branch circuits in CAT III, and service-entrance equipment in CAT IV. Choose the category and voltage for the location, rather than comparing voltage ceilings alone.

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01CAT II+Plug-in appliances & tools

Receptacle-connected loads, such as household appliances and portable tools. The category describes the measurement environment; it does not give permission to work on live equipment.

Sources: 1: CAT II includes household appliances, portable tools and other receptacle-connected loads.

02CAT III+Fixed wiring & distribution

The distribution part of the building installation, including distribution-panel devices and fixed-installation equipment. This is a different environment from a plug-in appliance.

Sources: 2: CAT III includes equipment in fixed installations and distribution-panel devices.

03CAT IV+Utility meter & service entry

The origin of the low-voltage installation, including electricity meters and the service entrance. Fluke also identifies the run between the meter and panel as CAT IV.

Sources: 3: CAT IV includes electricity meters, the service entrance and the run between meter and panel.

Illustrative locations, not a testing procedure. Match both the measurement category and voltage rating to the job. The lowest-rated meter, lead, probe or accessory limits the setup.

Source notes5 references+

1. 1

   CAT II includes household appliances, portable tools and other receptacle-connected loads.

   media.fluke.com ↗ — source for CAT II includes household appliances, portable tools and other receptacle-connected loads.

   Appliance, portable tools, and other household and similar

2. 2

   CAT III includes equipment in fixed installations and distribution-panel devices.

   media.fluke.com ↗ — source for CAT III includes equipment in fixed installations and distribution-panel devices.

   distribution panel devices

3. 3

   CAT IV includes electricity meters, the service entrance and the run between meter and panel.

   media.fluke.com ↗ — source for CAT IV includes electricity meters, the service entrance and the run between meter and panel.

   Electricity meters, primary overcurrent protection equipment

4. 4

   Probes, test leads and adapters need the correct measurement category, voltage and amperage ratings.

   assets.fluke.com ↗ — source for Probes, test leads and adapters need the correct measurement category, voltage and amperage ratings.

   Use only correct measurement category (CAT), voltage, and amperage

5. 5

   The lowest-rated component limits the measurement-category rating of the setup.

   assets.fluke.com ↗ — source for The lowest-rated component limits the measurement-category rating of the setup.

   Do not exceed the Measurement Category (CAT) rating of the lowest

The 107 manual says the lowest-rated meter, probe or accessory limits the system. Higher-rated leads do not upgrade an MM420 or 117 to CAT IV.

Those lead details come from Klein's manual, TL75 documentation and TL175 documentation.

Resolve the model and kit before ordering

One unresolved 87V conflict: its page's comparison chart claims a 3 m drop test, but its general specifications say 1 m. We cannot reconcile those claims. The MAX's documented 4 m with holster is the clearer choice when drop protection drives the purchase.

The 101 manual also documents Data Hold, while its regional page says “Hold: No.” Check the exact locally supplied model and manual before relying on that feature.

1. 1

   Match the model

   Confirm MM420, 117, 87V or 87V MAX on the instrument and package.

2. 2

   Match the needed function

   Check small-current ranges, temperature, LoZ and the location's CAT requirement.

3. 3

   Match the accessories

   Compare standard leads and probes with CAL, clamp-meter and E2 packages; confirm local support.

How we choose

We researched manufacturer product pages, manuals and accuracy tables; we have not physically tested these meters. The picks prioritize documented functions, category ratings, included accessories and the task a reader needs to complete. Conflicting maker claims remain identified rather than resolved by guesswork. Our selection method explains the wider process; beginners can continue with how to use a multimeter.

Verdict

Buy MM420 for home and hobby work needing temperature and small-current ranges, 117 for LoZ and non-contact electrical troubleshooting, or 87V MAX when its ruggedness and industrial functions earn their place. Pick 107 for pocket carry when True RMS is unnecessary. If you already own an 87V, identify the missing capability before buying a MAX.