COMPARISON · MULTIMETERS
Fluke 115 vs Klein MM720: Which Is Better for Professional Use?
Fluke 115 vs Klein MM720 is a rare case where the cheaper meter carries the bigger spec sheet. If you work at service entrances, on PV strings above 600 V, on 4–20 mA loops or on furnace flame sensors, buy the MM720: it is CAT IV 600V, reads to 1000 V and resolves 0.1 µA. Pay the Fluke 115's premium (about two and a half times the Klein on Amazon when we checked) only for its tighter DC volts, 9,999 µF capacitance and 3-year warranty.
By the OhmSavvy Research Team ·
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Fluke 115
4.8★★★★★The same Fluke reliability as the 117, in the same body, without the electrician-specific extras (NCV, AutoVolt, LoZ).
Klein Tools MM720
4.6★★★★★CAT IV 600V, 1000V, LoZ and True RMS at a budget price, the most panel-ready meter in this tier.
Specs side by side
| Fluke 115 | Klein Tools MM720 | |
|---|---|---|
| Rating | 4.8★★★★★ | 4.6★★★★★ |
| Accuracy | True RMS | True RMS, 6,000-count |
| Safety rating | CAT III 600V | CAT IV 600V / CAT III 1000V |
| Auto-ranging | Yes | Yes (manual RANGE button) |
| Best for | Field technicians, general electrical and electronics work | Electricians working panels and feeders |
| Safety category | CAT III 600V | CAT IV 600V / CAT III 1000V |
| Max voltage | 600V AC/DC | 1000V AC/DC |
| DC volts accuracy (6–600 V) | ±(0.5% + 2) | ±(0.8% + 3) |
| Lowest current range | 6.000 A (1 mA steps) | 600.0 µA (0.1 µA steps) |
| LoZ (ghost-voltage) mode | No | Yes, input >3 kΩ |
| Capacitance | To 9,999 µF | To 6,000 µF |
| Temperature | No | -40°F to 1832°F |
| Drop / ingress | Not stated in our sources | 2 m drop, IP42 |
| Weight / battery | 550 g, one 9V (about 400 h) | 345 g, 2 × AAA (life not stated) |
| Warranty | 3 years | Not stated in the manual |
Specs checked against manufacturer documentation and official Amazon listings. Fluke 115 is hands-on tested by OhmSavvy; the Klein Tools MM720 assessment is desk research. How we research.
Key differences
- →Only the MM720 is rated for CAT IV locations: CAT IV 600V and CAT III 1000V, against the Fluke 115's CAT III 600V.
- →The MM720 reads current from a 600.0 µA range at 0.1 µA; the 115's smallest current range is 6 A, at 1 mA steps.
- →The MM720 has a LoZ input (above 3 kΩ) for ghost voltages and a thermocouple input; the 115 has neither.
- →The Fluke's DC volts spec is tighter: ±(0.5% + 2) against Klein's ±(0.8% + 3) on the 6 V to 600 V ranges.
- →The 115 measures capacitance to 9,999 µF; the MM720 stops at 6,000 µF.
- →Fluke publishes a 3-year warranty and about 400 hours from one 9V battery; Klein's manual states neither figure for the MM720.
Where the MM720 can go and the Fluke 115 can't: CAT IV and 1000 V
The first question for a working electrician is where the probes will land. Fluke rates the 115 at CAT III 600V, which covers panelboards, feeders and branch circuits inside the building. Klein rates the MM720 at CAT IV 600V and CAT III 1000V, so its rating extends to the origin of the installation: the meter base, the service drop and the line side of the main disconnect. Klein's manual also asks for CAT IV rated test leads with it, so check that the leads in your pouch match before relying on that rating.
The voltage ceiling matters on solar work. A residential string inverter's DC input can sit well above 600 V on a cold morning, and the 115 simply isn't rated for that. Worked example on published specs: an illustrative 800 V DC string reads on the MM720's 1000 V range in 1 V steps at ±(1.0% + 3 digits), so ±(8 + 3) = ±11 V. That's plenty to confirm a string is producing and to compare strings against each other. Our solar panel testing guide covers the procedure.
Small currents: a 4–20 mA loop and a flame sensor on each meter
The 115 is built for amps. Its current input has two ranges, 6.000 A and 10.00 A, so the finest step it can show is 1 mA. The MM720 starts at a 600.0 µA range and steps up through 6000 µA, 60.00 mA, 600.0 mA and 6.000 A before reaching 10 A. For controls and HVAC technicians that is the most important difference on this page.
The arithmetic, using each maker's DC current spec: the 115 is ±(1.0% + 3 digits) on its 6 A range, so a 12 mA reading carries ±(0.12 + 3) ≈ ±3.1 mA. On a 4–20 mA loop, where the whole span is 16 mA, that is about a fifth of full scale, too coarse to tell a transmitter at 50% from one at 65%. The MM720's manual groups its 6000 µA to 6 A DC ranges at ±(1.5% + 3 digits), so the same 12.00 mA reading carries ±(0.18 + 0.03) = ±0.21 mA, around 1.3% of span.
Bars use a logarithmic scale: each step is ten times the last.
Flame-rectification sensors are harder still: their signal is typically a few microamps (check the furnace maker's figure for your unit), far below the 1 mA step the 115 can display. The MM720's 600.0 µA range shows it in 0.1 µA steps. If loops or flame sensors are a weekly job, see our 4–20 mA loop testing picks and how to measure microamps.
What the Fluke 115's premium actually buys
On paper the MM720 wins most rows, so it is worth being precise about the 115's advantages. The first is DC voltage: ±(0.5% + 2) against ±(0.8% + 3). On a 24.00 V DC control supply that works out to ±0.14 V on the Fluke and ±0.22 V on the Klein, a real but small gap that matters mainly when you are checking a supply against a tight tolerance. The second is capacitance: the 115 reads to 9,999 µF, while the MM720 shows overload above 6,000 µF, so large filter capacitors in drives and inverters are a Fluke-only test.
The third is support. Fluke publishes a 3-year warranty for the 115 and rates its single 9V battery for about 400 hours without the backlight. Klein's MM720 manual sends you to its website for warranty terms and gives no battery-life figure. Finally, the 115 is a meter we bought and tested on our own bench; our view of the MM720 comes from Klein's manual and product page rather than bench time, and the Fluke 115 review sets out what that testing covered.
What the premium does not buy
Job by job: which meter fits the call
| Job | Fluke 115 | Klein MM720 |
|---|---|---|
| Line side of a meter base | Not rated (CAT III only) | Rated, CAT IV 600V |
| 240 V dryer or range receptacle | Yes, True RMS, 0.1 V steps | Yes, True RMS, 0.1 V steps |
| 800 V DC PV string (illustrative) | Over its 600 V limit | 1 V steps, ±11 V |
| 4–20 mA loop at 12 mA | 0.012 A, ±3.1 mA | 12.00 mA, ±0.21 mA |
| Furnace flame sensor (µA) | Can't resolve it | 600.0 µA range, 0.1 µA |
| Ghost voltage on an open neutral run | No LoZ | LoZ input >3 kΩ |
| 8,000 µF filter capacitor | Within range (to 9,999 µF) | Overload (6,000 µF max) |
| Supply-air temperature | No input | Thermocouple, to 1832°F |
Both meters handle the bread-and-butter calls equally: receptacles, 240 V appliance circuits, motor current up to 10 A and continuity. The split appears at the edges of the job. For a broader field of options, our best multimeter for electricians ranks the MM720 against the Fluke 117 and 87V.
Match the meter's rating to the point you probe
Choose the Fluke 115 if…
- ✓Your work stays on branch circuits and equipment rated CAT III 600V or below
- ✓You check large electrolytic capacitors above 6,000 µF
- ✓You want Fluke's published 3-year warranty and a 9 V battery rated for about 400 hours
Choose the Klein Tools MM720 if…
- ✓You test at meter bases, service disconnects or other CAT IV locations
- ✓You need microamp or milliamp resolution for flame sensors or 4–20 mA loops
- ✓You want LoZ for ghost voltages and a thermocouple input in the same meter
Neither if…
You want non-contact voltage detection built in. Neither the 115 nor the MM720 lists NCV; the Fluke 117 adds VoltAlert in the 115's body, and the KAIWEETS HT118A pairs NCV with a µA range at a budget price.
The bottom line
For professional electrical work the Klein MM720 is the better buy: CAT IV 600V, 1000 V, LoZ, temperature and a 0.1 µA range at well under half the Fluke's price. The Fluke 115 earns its premium only if you stay on CAT III circuits and value tighter DC accuracy, a 9,999 µF capacitance range and Fluke's 3-year warranty.
Frequently asked questions
Is the Klein MM720 safe to use on a 480 V panel?+
Yes, by its rating. Klein rates the MM720 CAT III 1000V, which covers a 480 V distribution panel with margin, and CAT IV 600V at the service entrance. The Fluke 115 is CAT III 600V, which also covers a 480 V panel but stops short of service-entrance work. Use CAT IV rated leads with the MM720 and proper arc-flash PPE either way.
Can the Fluke 115 read a 4–20 mA signal at all?+
It can show it, but coarsely. The 115's lowest current range is 6 A with 1 mA resolution, so a 12 mA signal reads as 0.012 A, and Fluke's ±(1.0% + 3 digits) spec makes the uncertainty about ±3 mA. That's enough to see whether a loop is alive, not to calibrate a transmitter. The MM720 shows 12.00 mA on its 60 mA range.
Does the MM720 have a non-contact voltage detector?+
No. Klein lists no NCV function for the MM720, and the Fluke 115 doesn't have one either. If you want a detector built into the meter, the Fluke 117 adds VoltAlert to the 115's design, and the KAIWEETS HT118A has NCV. Many electricians carry a separate pen-style tester anyway, so this may not decide your purchase.
Which meter is more accurate for DC voltage?+
The Fluke 115. Fluke specifies ±(0.5% + 2 digits) for DC volts; Klein's manual gives the MM720 ±(0.8% + 3 digits) on the 6 V to 600 V ranges. On a 24 V control supply that is about ±0.14 V against ±0.22 V. For checking control power and batteries either is adequate; the gap matters on tight-tolerance supplies.
Why is the Klein MM720 so much cheaper if it has more features?+
We can only compare what each maker publishes, not their costs. On the published specs, the Fluke's case rests on tighter DC accuracy, wider capacitance, a stated 3-year warranty and long 9V battery life. The MM720 has the wider safety rating and function list. We hands-on tested the 115; the MM720 verdict is desk research from Klein's documents.
Is the MM720 waterproof?+
Not waterproof, but it is rated IP42 and survives a 2 m drop, per Klein's manual. IP42 means protection against dripping water, not rain or immersion, and Klein's manual says to use it indoors and dry the jacks after any contact with water. Our Fluke 115 sources don't state an IP rating, so treat both as dry-location tools.
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