Fluke 177 vs Fluke 179: Features and Accuracy Compared

Specs side by side

Specs checked against manufacturer documentation and official Amazon listings. Desk research, not bench testing. How we research.

Key differences

• →Only the 179 measures temperature: −40 °C to 400 °C at ±(1.0% + 10) with 0.1 °C resolution, using the 80BK probe Fluke includes.
• →Every electrical accuracy line Fluke publishes is the same on both, including the 0.09% DC volts spec.
• →Both share the backlit display with analog bar graph, CAT IV 600V / CAT III 1000V, the 420 g case, about 200 hours on a 9 V cell and a lifetime warranty.
• →Fluke's 179 page contradicts itself in places: its comparison table lists 9,999 µF and a 400 °F top temperature, and names µA as a function, while its spec table gives 10,000 µF, 400 °C and 0.01 mA best current resolution. We follow the spec table.
• →Neither has LoZ, non-contact voltage or a low-pass filter.

Fluke 177 vs 179 at a glance

OhmSavvy hasn't hands-on tested either meter, so our editorial scores (4.7 for the 179, 4.6 for the 177) rest on Fluke's published specifications. Everything below comes from the two Fluke product pages, and the tolerances are our arithmetic on Fluke's numbers, not measurements.

The two accuracy tables, line by line

Fluke prints a short accuracy table on each 170-series page, giving the best accuracy, finest resolution and maximum for every function. Here are the 177 and 179 tables merged. The only row that differs is the last one.

Fluke footnotes these as the best accuracy for each function, which usually means the most favorable range and frequency band. Individual ranges can be looser, so treat every worked figure below as the best case. The users manual holds the full per-range tables.

Worked tolerances for everyday readings

A spec of ±(a% + n) means a percent of the displayed value plus n steps of the last digit. On a 6,000-count meter the step depends on the range: 0.001 V on 6 V, 0.01 V on 60 V, 0.1 V on 600 V. The table below works that out for readings an electrician or technician takes every week. Because the tables match, each row holds for the 177 and the 179 alike.

Two things stand out. At low readings the count part can be as large as the percentage part: on 24 V, the two counts (20 mV) nearly equal 0.09% of the reading (21.6 mV). And AC volts are about ten times looser than DC on both meters, so a 120 V receptacle that reads anywhere from 118.5 V to 121.5 V on the display is inside the published tolerance if the true value is 120.0 V. For a 4–20 mA loop the ±0.23 mA allowance at full scale is just under 1.5% of the 16 mA span, which is fine for finding a dead transmitter but not for calibrating one. Our guide to measuring milliamps covers the series connection.

How the 179's temperature spec behaves

The temperature line, ±(1.0% + 10), has a large count term. At 0.1 °C resolution, ten counts are a fixed 1.0 °C, so near room temperature that fixed part is most of the allowance, and only at a few hundred degrees does the percentage part take over.

These are the meter's figures alone. Any thermocouple probe has its own tolerance, and the reading you see includes both, so the real uncertainty is wider than the bars. In practice that means the 179 is right for trend and difference work: supply versus return air, a bearing that runs warmer than its twin, a heat sink climbing under load. For a temperature you must certify to a fraction of a degree, use a dedicated thermometer. To check that a probe itself is sound, see how to check a thermocouple with a multimeter.

Where Fluke's 179 page disagrees with itself

The comparison table further down Fluke's 179 page doesn't match its own spec table in three places. The spec table is more detailed and agrees with the 177 page, so we use it throughout.

The current row matters most. If the 179's finest step is 0.01 mA (10 µA), it can't resolve a furnace flame-sensor signal of a few microamps, whatever the comparison table says. For that check, look at the Fluke 116 or 87V, discussed in our Fluke 87V vs 179 comparison.

Which features justify paying more for the 179?

Upgrades usually bundle several improvements, so buyers assume the dearer model is better across the board. This pair breaks that habit. Go through everything a buyer might hope the step up delivers, and only two lines change: the temperature function itself and the 80BK probe that ships with it. Every other item on the list is either identical on the 177 or missing from both meters.

That makes the value test unusually simple. Count how often a temperature reading would save you fetching another instrument. If it is part of most service calls, as on HVAC, motor and bearing checks, the 179 pays for itself in time and in the probe you don't have to buy separately. If you can't name a job in the last month where you needed one, the extra spend buys a dial position that will sit unused, and the 177 is the better value. Nothing about the 179 makes your volts or amps readings more trustworthy.

Which jobs need the 179's extra function

Because the electrical specs are identical, the right question is how often you'd reach for a temperature reading. If the answer is weekly, carrying the 179 saves a second instrument. If it is never, the 177 is the same meter for less.

If neither temperature nor the tight DC spec appeals, step down: the Fluke 175 vs 177 comparison covers the cheapest 170-series meter. If your work is mostly building wiring, the Fluke 177 vs 117 page weighs LoZ and VoltAlert against the 170 series. HVAC buyers should also read our best multimeter for HVAC technicians guide.

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