Delta
The delta symbol is Δ in capitals and δ in lowercase. Tap one to copy it, then see the codes, how to type delta in Excel, Word and on a Mac, and what it means, plus the triangle and increment lookalikes.
By Maya Chen, lettering designer and type educator · Checked by Jordan Hale · · How we review content
Copy delta
One tap copies one character. Each form below has its own code point.
Key facts
- Delta is the fourth letter of the Greek alphabet, with a numeral value of 4; capital Δ is U+0394 and lowercase δ is U+03B4.
- Capital Δ usually means a finite change (final minus initial), while lowercase δ usually means a small change, a Kronecker or Dirac delta, or a partial charge.
- The increment sign ∆ (U+2206), which a US Mac types with Option+J, looks like Δ but is a different character.
- In Excel and Google Sheets, =UNICHAR(916) returns Δ and =UNICHAR(948) returns δ.
- The triangles △ and ▲ are shapes, not the letter, so a search for Δ does not find them.
Codes for every form
Unicode names and code points for each form, with the escapes you need in HTML, CSS, JavaScript and LaTeX.
| Form | Unicode name | Code point | Decimal | HTML | CSS / JavaScript | LaTeX |
|---|---|---|---|---|---|---|
| delta, capital | GREEK CAPITAL LETTER DELTA | U+0394 | 916 | Δ Δ | \0394 / \u0394 | \Delta |
| delta, lowercase | GREEK SMALL LETTER DELTA | U+03B4 | 948 | δ δ | \03B4 / \u03B4 | \delta |
How to type delta
The quick methods for this letter. Step-by-step instructions for each system, and what we have and have not tested, are on how to type Greek letters.
| Method | What to do |
|---|---|
| Copy and paste | Use the buttons at the top of this page. Pasted text is plain Unicode. |
| Word on Windows | Type the code, then press Alt+X: 0394 for Δ; 03B4 for δ. Windows steps. |
| Excel and Google Sheets | =UNICHAR(916) for Δ; =UNICHAR(948) for δ. Office steps. |
| Windows Alt code | Hold Alt and type on the numeric keypad: 235 gives δ. From the old code page 437 table; not tested by us on a live Windows machine. |
| Phone | Add a Greek keyboard: iPhone and iPad or Android. |
| Web page or LaTeX | Δ, \Delta for Δ; δ, \delta for δ. LaTeX commands work in math mode. |
Characters that look like delta
These are separate characters, so each has its own code point. Copy the one that matches the job.
How to say delta
| Reading | Value |
|---|---|
| English (maths and science) | DEL-tuh, /ˈdɛltə/ |
| Modern Greek | /ð/, like the "th" in "this". The Greek name is δέλτα, /ˈðelta/. |
| Classical Greek (reconstructed) | /d/ |
The sound shifted between ancient and modern Greek: ancient delta was a plain d and modern delta is the voiced "th" of "this" or "that". Modern Greek writes a d sound from foreign words with ντ. English speakers say "DEL-tuh" for the symbol in every field. See the pronunciation page for the whole alphabet.
What delta means, field by field
"Standard" marks a definition or notation that is fixed, such as an SI unit or a named function. "Convention" marks common practice that varies by author, so check the definitions in your own text. The same letter often means different things in different fields; the full table for every letter is on Greek letters in math and science.
Mathematics and physicssymbol ΔConvention
A finite change: Δx = x₂ − x₁ is the final value minus the initial value. A slope is Δy/Δx. Δt is an elapsed time and ΔE a change in energy.
Mathematicssymbol δᵢⱼStandard
The Kronecker delta, equal to 1 when i = j and 0 otherwise. It picks out the diagonal of a matrix, so the identity matrix has entries δᵢⱼ.
Mathematics and physicssymbol δ(x)Standard
The Dirac delta, a spike that is zero everywhere except at 0 and whose integral over the line is 1. It is a distribution rather than an ordinary function.
Analysissymbol δConvention
In the epsilon-delta definition of a limit, δ is the tolerance on the input that guarantees the output stays within ε. It is conventionally a small positive number.
Calculussymbol ΔConvention
Some texts write the Laplacian as Δ, meaning ∇². Others use Δ only for finite differences, so check which the book means.
Chemistrysymbol Δ, δConvention
A Δ over a reaction arrow means heat is applied. ΔH is the enthalpy change, δ+ and δ− mark partial charges on atoms, and δ is the chemical shift in NMR spectra, given in ppm.
Statisticssymbol ΔConvention
The difference between two group means, sometimes called the effect size or Δ in the text. It is the same finite-change idea applied to averages.
Financesymbol deltaConvention
For options, delta is how much the option price moves for a one-unit move in the underlying asset. A delta of 0.5 means roughly half a unit of price change.
Lookalikes and common mistakes
Mac Option+J gives ∆, not Δ
On a US Mac layout, Option+J types ∆ (INCREMENT, U+2206). It looks like Greek capital delta but is a maths symbol with a different code point. If it matters, copy Δ from the button above or type it with a Greek keyboard. We have not re-tested on every macOS version.
A triangle is not a delta
People paste △ or ▲ for delta in notes and chat. They are shapes, not the letter, so searches for Δ will not find them and screen readers read them as triangles. Use Δ for the letter.
∂ is not δ
The partial derivative sign ∂ is a curly d and is often misread as lowercase delta. In calculus of variations, δ marks a variation and ∂ a partial derivative, which are different ideas.
∇ is nabla, not upside-down Δ
The gradient operator ∇ (NABLA, U+2207) looks like Δ flipped, and the Laplacian is written ∇² or Δ depending on the author. They are different characters, so do not swap them to save a glyph.
Capital Δ and Cyrillic Д
Cyrillic Д (U+0414) has small feet and is a different capital letter that sounds like d. Greek Δ is a plain triangle with a base line, and the two are not interchangeable.
Where does the delta symbol come from?
Delta is the fourth letter of the Greek alphabet, with a numeral value of 4. It was derived from the Phoenician letter dalet, and the Latin D and the Cyrillic Д descend from it. The triangular capital gave river deltas their name. All of this is in the Wikipedia article on delta, which is the source for the history here.
Capital Δ or lowercase δ: which one do you need?
A rule of thumb that works for most readers: capital Δ is big and finite, lowercase δ is small. Δx = 5 means x changed by 5. δx usually means an arbitrarily small change in x, or in the calculus of variations a variation of x. Texts that use only one of the two will say so, so look at the definitions first.
Δ has more uses than it has room for here. It is the change in a value, the difference between group means, the heat marker over a reaction arrow, and the symbol on the Delta-V budgets used in spaceflight, where it stands for a change in velocity. In every case the idea is the same: the symbol means “the amount by which this changes”.
How do you type and paste delta without surprises?
Three input methods produce the wrong character without warning: the Mac Option+J shortcut gives ∆ (INCREMENT), a triangle emoji or shape gives △ or ▲, and a legacy Windows font may substitute its own Δ glyph. If a pasted Δ matters, for example in a name or a formula that will be parsed by software, check its code point. The Unicode page shows how to see it, and the copy buttons above always give U+0394 and U+03B4.
In HTML, Δ and δ work. In CSS, the escapes are \0394 and \03B4. In JavaScript or Python strings, \u0394 and \u03b4. In LaTeX math, \Delta and \delta, and both commands need math mode (or the textgreek package, which has \textDelta and \textdelta, for running text).
Sources
These sources back the facts on this delta symbol page. Meanings differ between fields, so rely on the definition your own text states.
- Wikipedia, Delta (letter) (history, pronunciation, symbol uses)
- Wikipedia, Greek letters used in mathematics, science, and engineering (secondary overview of field conventions)
- Unicode Greek and Coptic code chart (PDF)
- Microsoft Support, UNICHAR function
- Field meanings are conventions and vary by author; where a definition matters, use the one your text gives.
Frequently asked questions
Basics
What does the delta symbol mean in math and science?
Why is a river delta called a delta?
What is the Kronecker delta?
Where it works
Where is the delta symbol used in chemistry and finance?
How it works
How do I type the delta symbol in Excel?
What is the delta symbol alt code?
How do I write the delta symbol in HTML and LaTeX?
Tips & limits
Is Δ the same as the increment sign ∆?
Is a triangle the same as the delta symbol?
Is ∂ the same as lowercase delta?
Related Greek pages and symbols
- Greek Letters in Math and ScienceGreek letters in math and science are conventional symbols: π is the circle constant, Δ a change, σ a standard deviation, λ a wavelength and Ω the SI ohm. Only a few meanings are fixed by standards, so they vary by field and author. Look up a letter below; each one lists its meanings grouped by field.
- How to Type Greek LettersHow to type Greek letters on any device: add a Greek keyboard on Windows, Mac, iPhone or Android, or use Alt+X in Word and UNICHAR in Excel for a single character. Copying from the alphabet page works everywhere. Each method notes what we verified and which traps to avoid.
- Greek Alphabet UnicodeThe Greek alphabet Unicode block, Greek and Coptic (U+0370 to U+03FF), holds all 24 letters: capitals at U+0391 to U+03A9 and lowercase at U+03B1 to U+03C9. This page lists each code point, HTML entity and LaTeX command, plus the micro sign, ohm sign and homoglyph traps.
- Math SymbolsTap a symbol to copy it. Every symbol shows its Unicode name and code point, and the page explains which lookalikes to avoid.
- Science SymbolsTap a symbol to copy it. Each shows its Unicode name and code point, with notes on the sign characters that are not the plain letters they look like.
- Greek AlphabetThe Greek alphabet has 24 letters, from alpha to omega, each with an uppercase and a lowercase form. Tap any letter to copy it, check its name, sound and numeric value in the table, or print a clean one-page chart. This page treats the letters as characters and symbols, not as a language course.