Ohm Symbol Copy and Paste (Ω, kΩ, MΩ)
Ohm (use this)
Unicode U+03A9 · HTML Ω · Alt code Alt+234 · Mac Option+Z
Tap any symbol to copy it. Each tap also adds it to the box above, so you can copy several together.
Codes for every symbol on this page (Unicode, HTML, Alt, Mac, Word)
| Symbol | Name | Unicode | HTML | Windows Alt code | Mac | MS Word |
|---|---|---|---|---|---|---|
| Ω | Ohm (use this) | U+03A9 | Ω | Alt+234 | Option+Z | 03A9 then Alt+X |
| Ω | Ohm sign (legacy) | U+2126 | Ω | - | - | 2126 then Alt+X |
| kΩ | Kilohm | U+006B U+03A9 | kΩ | - | - | - |
| MΩ | Megohm | U+004D U+03A9 | MΩ | - | - | - |
| ℧ | Mho (old unit) | U+2127 | ℧ | - | - | 2127 then Alt+X |
The ohm symbol Ω is the unit of electrical resistance, so a 220 Ω resistor resists current twice as much as a 110 Ω one. The unit is named after the German physicist Georg Simon Ohm, and the sign is borrowed from the Greek capital letter omega.
Copy Ω, kΩ or MΩ from the grid above. This page covers how resistance is written in formulas and circuit diagrams, what the Ω setting on a multimeter means, and how to type the ohms symbol on any device.
Resistance Unit Symbol and Its Multiples
The resistance unit symbol is Ω. Real resistors range from a fraction of an ohm to millions of ohms, so prefixes are used:
| Written | Name | Value | Typical example |
|---|---|---|---|
| mΩ | milliohm | 0.001 Ω | Thick copper cable |
| Ω | ohm | 1 Ω | Speaker rating (4 Ω or 8 Ω) |
| kΩ | kilohm | 1,000 Ω | Common resistor (10 kΩ) |
| MΩ | megohm | 1,000,000 Ω | High-value resistors, insulation tests |
The mega ohm symbol is MΩ with a capital M. A small m would mean milli, a billion times smaller, so the case matters. For tiny values like µΩ, see the micro symbol page.
Ohm's Law Symbol and Formula
Ohm's law links voltage, current and resistance:
V = I × R
- V = voltage in volts (V)
- I = current in amperes (A)
- R = resistance in ohms (Ω)
Example: a 12 V battery across a 4 Ω resistor gives I = 12 ÷ 4 = 3 A. There is no single "Ohm's law symbol"; people often draw the V, I, R triangle (V on top, I and R below) to remember the three forms V = IR, I = V ÷ R and R = V ÷ I.
Notice that the quantity resistance is written R, while the unit is Ω. So write R = 100 Ω, not Ω = 100. The resistivity of a material, ρ, is measured in Ω m; see the rho symbol page.
Resistance Symbol in Circuits and on a Multimeter
In circuit diagrams, a resistor is drawn as a small rectangle (the style used in Indian textbooks and most of the world) or as a zigzag line (common in American books).
- Variable resistance symbol: the same resistor shape with an arrow drawn diagonally across it. A rheostat or a volume knob is a variable resistor.
- Multimeter resistance symbol: on the dial, the resistance section is marked with Ω, often with ranges like 200, 2k, 20k, 200k and 2M. Turn the dial to Ω, switch off the circuit power, and touch the probes across the part.
- If the display shows OL or 1 on the left, the resistance is higher than the range or the circuit is open.
A meter made only for measuring resistance is called an ohmmeter. Always test with the power off; this is general safety information, so follow the meter's manual.
How to Type the Ohm Symbol in Keyboard, Word and Excel
| Where | Method |
|---|---|
| Windows | Alt+234 on the number pad (Num Lock on) |
| Mac | Option+Z |
| Ohm symbol in Word | Type 03A9, then Alt+X; or Insert > Symbol > Greek and Coptic |
| Ohm symbol in Excel | =UNICHAR(937), or a custom number format 0 "Ω" so values stay numeric |
| Google Docs | Insert > Special characters, search "omega" |
| HTML | Ω |
In Excel, the custom format trick is handy for a parts list: the cell shows "470 Ω" but you can still sort and add the numbers.
Ohm symbol text without Ω: on plain keyboards people write "ohm" or use R. Resistor markings and some circuit diagrams also put R or K in place of the decimal point: 4R7 means 4.7 Ω and 4K7 means 4.7 kΩ.
Ω vs Ω: Which Ohm Character Is Correct?
Unicode has two characters that look the same:
- Ω U+03A9, Greek capital letter omega
- Ω U+2126, the ohm sign
Unicode recommends using the Greek capital omega U+03A9 for the ohm unit as well. The separate ohm sign was kept only so old documents convert correctly, and some fonts do not even include it. The Alt and Option shortcuts above already give the recommended character. For the Greek letter and its maths uses, visit the omega symbol page.
Mho ℧ and Siemens
Conductance is the opposite of resistance: G = 1 ÷ R. It used to be measured in mho (ohm spelt backwards), shown by the upside-down sign ℧. Today the SI unit is the siemens (S), and 1 S = 1 ÷ Ω. You may still meet ℧ in older electrical books. More unit signs are on our physics symbols and Greek letters pages.
Frequently asked questions
What is the symbol of ohm?
The symbol of ohm is Ω, the Greek capital letter omega. It is the SI unit of electrical resistance.
Is the ohm symbol a Hindu symbol?
No. Some people search "ohm symbol hindu" because ohm and Om sound alike. The sacred Hindu symbol is Om (ॐ), which is unrelated to the electrical unit Ω. See the om symbol page for its meaning.
What is the resistance symbol in physics?
Resistance as a quantity is written R, and its unit is the ohm (Ω). In circuit diagrams, a resistor is shown as a rectangle or a zigzag line.
Why is the ohm symbol a Greek letter?
A common explanation is that a capital O could be confused with the digit 0, while omega starts with an "o" sound like ohm. Whatever the reason, Ω is now the standard SI symbol.
How do I type the ohm symbol on my phone?
On most Android keyboards, tap ?123, then =\< and look for Ω among the extra symbols; if your keyboard does not have it, copy it from this page. On iPhone it is not on the default keyboard, so copy it from this page or add a Greek keyboard.