Epsilon Symbol Copy and Paste (ε ϵ Ε)
Small epsilon
Unicode U+03B5 · HTML ε · Alt code Alt+238
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 |
|---|---|---|---|---|---|---|
| ε | Small epsilon | U+03B5 | ε | Alt+238 | - | 03B5 then Alt+X |
| Ε | Capital epsilon | U+0395 | Ε | - | - | 0395 then Alt+X |
| ϵ | Lunate epsilon | U+03F5 | ϵ | - | - | 03F5 then Alt+X |
| € | Euro sign (not epsilon) | U+20AC | € | Alt+0128 | Option+Shift+2 | 20AC then Alt+X |
| ∈ | Element of (not epsilon) | U+2208 | ∈ | - | - | 2208 then Alt+X |
The epsilon symbol ε is the fifth letter of the Greek alphabet and makes a short "e" sound, as in "pen". In Indian physics classes it is best known from ε₀, the permittivity of free space in Coulomb's law, but engineers and mathematicians use it too.
Copy ε, its capital Ε or the rounded form ϵ from the grid. We have also placed two look-alikes there, the set sign ∈ and the euro sign €, because they are often mistaken for epsilon. The sections below explain the difference.
Epsilon Naught: The "Epsilon Not" Symbol ε₀
Many students type "epsilon not symbol" into search when they mean epsilon naught, written ε₀ (epsilon with a small zero below). "Naught" is an old word for zero. ε₀ is the permittivity of free space, a constant that tells how easily an electric field forms in a vacuum.
- Value: about 8.854 × 10⁻¹² C²/N·m² (same as F/m).
- It appears in Coulomb's law: F = (1/4πε₀) × q₁q₂/r².
- The number 1/4πε₀ is about 9 × 10⁹ N·m²/C², which is what you use in most sums.
In a material, permittivity is written ε, and ε/ε₀ is the dielectric constant (often K or κ). The formula uses the pi symbol too, so keep both handy.
How to type ε₀
In Word, type ε, then press Ctrl+= to switch on subscript, type 0, and press Ctrl+= again to switch it off. In Google Docs, the subscript shortcut is Ctrl+,. In a Word equation, type \epsilon_0 and press Space.
Other Uses of ε in Science and Maths
| Field | ε means |
|---|---|
| Strength of materials | Strain: change in length divided by original length (no unit) |
| Calculus | A very small positive number in the ε-δ definition of a limit |
| Heat radiation | Emissivity, between 0 and 1 |
| Statistics | The random error term in a regression model |
Example for strain: a 2 m wire stretches by 1 mm, so ε = 0.001 ÷ 2 = 0.0005. In the limit definition, ε works with δ; see the delta symbol page.
ε vs ϵ vs ∈ vs €
- ε is the usual small epsilon, shaped like a backwards 3.
- ϵ is the lunate epsilon, a half-moon with a bar. It is the same letter in a different style; some maths books prefer it to keep ε free for another meaning.
- ∈ means "is an element of" in set theory: 3 ∈ {1, 2, 3}. It looks like ϵ but is a maths operator, not a letter. More set signs are on the math symbols page.
- € is the euro currency sign. Its design was inspired by epsilon and the first letter of "Europe", with two lines for stability. See the euro symbol page.
- Ε (capital epsilon) looks exactly like English E.
How to Type the Epsilon Symbol
- Windows: Alt+238 on the number pad (Num Lock on) gives ε.
- Word: type 03B5 then Alt+X. For ϵ use 03F5, for ∈ use 2208.
- Word or Google Docs equations: \epsilon, then Space. Depending on the editor, \epsilon and \varepsilon give the two shapes.
- Mac: no Option shortcut for ε. Use the Character Viewer (Control+Command+Space). For €, press Option+Shift+2.
- Phone: copy ε from the grid, or switch to a Greek keyboard.
See the Greek letters page for the full alphabet.
Frequently asked questions
What is the symbol of epsilon?
Small epsilon is ε (or the rounded ϵ) and capital epsilon is Ε. Physics and maths use the small form.
What is epsilon naught?
Epsilon naught, ε₀, is the permittivity of free space, about 8.854 × 10⁻¹² F/m. It appears in Coulomb's law and in capacitor formulas.
Is ∈ the same as epsilon?
No. ∈ is the set theory sign for "belongs to". It was originally based on epsilon, but today it is a separate character, so use ∈ for sets and ε for quantities.
What is the Alt code for epsilon?
Alt+238 gives small ε on Windows using the number keypad. Capital Ε and lunate ϵ have no Alt code; use the Word code then Alt+X instead.
Was the euro sign based on epsilon?
Yes, the € sign was inspired by the Greek epsilon, linked to Europe. It is still a currency sign, not a Greek letter, and has its own Alt code, Alt+0128.