Ohm symbol (Ω)
The resistance setting. Ω, the Greek capital omega, is the symbol for the ohm, the unit of electrical resistance.
How to read it
Fluke’s guide to the multimeter dial marks resistance Ω, Klein Tools lists the symbol as resistance in ohms, and Extech as ohms. The display adds a multiplier: k is kilo, 10³, and M is mega, 10⁶, in Klein’s and Extech’s symbol lists, so kΩ is thousands of ohms and MΩ millions. Fluke’s 114, 115 and 117 read from 0.1 Ω to 40 MΩ, and Klein’s MM400 and Extech’s EX330 also reach 40 MΩ.
On many meters the same position holds Continuity symbol: Klein’s MM400 switches between continuity and resistance with its SEL button.
Also searched as: ohms setting, omega symbol on a multimeter, resistance symbol, Ω.
These pages describe what each setting, marking and reading means. They are not instructions for measuring anything. Meters differ between makers and models: the meter’s own manual says what each of its symbols means, which measurements it is rated for, and how to use it safely.
OL on the resistance setting
A resistance too high for the range reads OL, which Fluke’s manual explains as an input too large for the selected range.
What the manuals say about live circuits
Klein’s manual says not to measure resistance or continuity on a live circuit, and Fluke’s manual says to disconnect circuit power and discharge high-voltage capacitors before testing resistance, continuity, diodes or capacitance.
Read next
- Next in Multimeter symbolsContinuity symbolThe continuity setting: the meter beeps when the resistance between its probes is below a low threshold set by the maker, and shows OL when the circuit is open. The dot with sound waves stands for the beeper.
- Ω, the ohm, is the Greek capital letter omega.OmegaOmega (Ω, ω) is the 24th and last letter of the Greek alphabet. The capital Ω is the symbol for the ohm, the SI unit of electrical resistance, and the small ω is angular frequency in physics.
More multimeter symbols
The same shape elsewhere
Browse symbols drawn with letters and numbers.
Sources
- Multimeter Symbols, Buttons, Dials, and Display, Fluke learning centre article, Fluke Corporation, Digital multimeter dial
- 114, 115, and 117 True-rms Multimeters: Users Manual, PN 2572573, July 2006, Rev. 1, 2/07, Fluke Corporation (copy hosted by UCL Electronic and Electrical Engineering), Safety information; Display; Rotary switch positions
- MM400 Auto-Ranging Digital Multimeter: Instruction Manual, MM400 instruction manual, Klein Tools (copy hosted by UBC Earth, Ocean and Atmospheric Sciences), Symbols on meter; Symbols on LCD; Warnings; Function buttons
- Mini Multimeter with Non-Contact Voltage Detector, Model EX330: User’s Guide, EX330-EU-ENG V4.2 1/08, Extech Instruments (copy hosted by Core Electronics), Display symbols and annunciators; Specifications
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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