Rho Symbol Copy and Paste (ρ Ρ ϱ)
Small rho
Unicode U+03C1 · HTML ρ
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 |
|---|---|---|---|---|---|---|
| ρ | Small rho | U+03C1 | ρ | - | - | 03C1 then Alt+X |
| Ρ | Capital rho | U+03A1 | Ρ | - | - | 03A1 then Alt+X |
| ϱ | Curly rho (varrho) | U+03F1 | ϱ | - | - | 03F1 then Alt+X |
The rho symbol ρ is the 17th letter of the Greek alphabet and the standard letter for density in physics and chemistry. It also stands for resistivity of a wire and for correlation in statistics.
A small warning before you copy: capital rho Ρ looks exactly like the English P, so in science you will nearly always want small ρ. Tap it in the grid above, or read on for its uses and typing methods.
Rho as the Density Symbol
The density symbol in physics is ρ. Density tells you how much mass is packed into each unit of volume:
ρ = m ÷ V, measured in kg/m³ (or g/cm³).
Quick examples:
- Water: about 1000 kg/m³, which is 1 g/cm³.
- A 2 kg block that fills 0.001 m³: ρ = 2 ÷ 0.001 = 2000 kg/m³.
- Anything with ρ less than water floats on water. That is why ice floats.
In fluid pressure you meet ρ again: P = ρ g h, the pressure at depth h in a liquid.
Resistivity Symbol ρ in Current Electricity
In the current electricity chapter, the same letter becomes the symbol of resistivity. Resistance of a wire depends on its material, length and thickness:
R = ρ L ÷ A
Here ρ is the resistivity, a property of the material alone. Its unit is the ohm metre (Ω m). Copper has a very low ρ, about 1.7 × 10⁻⁸ Ω m, which is why it is used for house wiring. Nichrome has a much higher ρ, so it is used in heater coils. See the ohm symbol page for Ω.
Rho Symbol in Physics: Which Density Uses Which Letter?
Not every "density" in physics is written with ρ. This table clears up a very common confusion:
| Quantity | Usual symbol | Unit |
|---|---|---|
| Mass density | ρ | kg/m³ |
| Volume charge density | ρ | C/m³ |
| Surface charge density | σ | C/m² |
| Linear charge density | λ | C/m |
| Current density | J (bold, a vector) | A/m² |
| Magnetic flux density | B | tesla (T) |
| Energy density | u (sometimes w) | J/m³ |
So the volume charge density symbol is ρ, but the current density symbol is J the magnetic flux density symbol is B, and the energy density symbol is usually u. For σ and λ, visit the sigma symbol and lambda symbol pages.
Rho in Statistics
In statistics, ρ is used for correlation:
- Spearman's rho measures how well two rankings agree, for example marks in maths and marks in physics for the same class.
- ρ is also used for the population correlation coefficient, while the sample value is written r.
Values run from −1 to +1. A value near +1 means the two lists rise together; near 0 means little relation.
How to Type Rho
Rho has no Alt code and no Mac Option shortcut. Choose any of these:
- Word:
03C1then Alt+X gives ρ. The curly variant ϱ is03F1then Alt+X. In an equation box,\rhoplus space also works. - Google Docs: Insert > Special characters, search "rho".
- Excel:
=UNICHAR(961). - Mac: Character Viewer with Control+Command+Space.
- Website: HTML code
ρ.
Common mistake: typing the English letter p for ρ. In handwriting the two look close, but ρ is drawn in one smooth stroke, starting at the bottom of the tail and curling into the round bowl. In typed work, always copy the real ρ.
Chi Rho Symbol
The chi rho symbol (☧) is an old Christian monogram made by placing the Greek letters Χ (chi) and Ρ (rho) on top of each other. They are the first two letters of "Christ" in Greek. It is still seen in churches and on religious art. Read more on the Christian cross symbol page, and see every Greek letter on the Greek letters hub.
Frequently asked questions
What is the symbol of rho?
The symbol of rho is ρ (small) and Ρ (capital). Scientists use the small ρ, because the capital is identical to the English P.
How do you pronounce rho?
Rho is pronounced "roh", like the word "row" (a row of chairs). The h is silent.
What is the difference between ρ and ϱ?
They are the same letter written in two styles. ϱ, often called varrho, has a curled tail and is used in some maths books when ρ already has another meaning.
Is resistivity the same as resistance?
No. Resistance R depends on the size of the wire, while resistivity ρ depends only on the material. Two copper wires of different lengths have different R but the same ρ.