Slash Symbols in Writing: When to Use a Backslash vs. a Forward Slash

There are forward slash (/), backslash (\) and vertical slash (|) symbols on a computer keyboard. The forward slash is the type you're most likely to see or use in writing.

• Forward (/) slashes serve many purposes in writing. They are commonly used to separate words, lines of poetry, abbreviations, dates, and fractions.
• Backslashes (\) are primarily used in computer coding. They appear in some technical writing, such as software manuals or user guides.
• Vertical (|) slashes, also called upright or straight slashes, are used in math and computer programming. A vertical slash stands for "it is true that" or "such that."

Memory tip: To differentiate the forward slash from the backslash, remember that the top part of the forward slash is in front of the bottom part. Since the vertical slash is straight up and down, that one's easy to remember.

Forward slashes may also be referred to as virgules or oblique symbols. Sounds pretty, right? It seems appropriate, given that slashes dance across many areas of writing. Forward slashes are commonly used in writing to separate certain words when they appear next to each other.

Forward slashes are also used to separate the words "and" and "or" (and/or) when they are used side by side in writing. This is much easier for readers to understand than the alternative, which would require writing the word "and" two times in a row.

• The professor instructed all students to bring a notebook and/or laptop to class.
• I can't wait to eat hamburgers and/or hot dogs at the cookout.
• When we visit the Hiwassee River next summer, I hope to go hiking and/or kayaking.
• Be sure to pack waterproof shoes and/or rain boots for your upcoming trip to Iceland.

There is no spacing on either side of the forward slash when it is used in this manner.

The forward slash can also be used in text as a substitute for the phrase and/or. This usage is most appropriate in informal pieces of writing. In this context, think of the forward slash as a visual depiction of the phrase and/or.

• At last week's speed dating event, there were instructions for every man/woman to stick to a three-drink maximum.
• If/when the professor arrives, we will begin reciting the poems we were assigned to memorize.
  
• Be sure to take an extra blanket/comforter when you go on an overnight boating adventure.
• The seasonal campground is only open for day use camping during the spring/summer months.

The forward slash should be placed directly between two words when used this way, without spacing before or after.

In its truest form, a forward slash is going to indicate a relationship between two things. It could indicate that the two things are closely related (connected) in some way, or it could indicate that there is opposition or conflict between them.

• During an election year, a politician might write, "I am committed to representing the interests of all citizens. We can't let political parties divide us. Red/blue, Republican/Democrat doesn't matter. We're all citizens striving for a better tomorrow."
  
• In a company where leaders don't agree on the best management style, the conflicting approaches might be the topic of a brainstorming session. The leader might say, "Our goal is to explore the advantages and disadvantages of participative/authoritarian approaches to supervision."
• When planning a trip to the moon, the resident astronaut might say, "In order to make a successful landing on the moon, we're going to take the Mars/Venus route into space."
  
• If two siblings were at odds over what type of cookies to make, Mom might say, "I don't know what we're going to do, but no matter what, our Scott/Marie cookies are going to be fabulous."

Do not leave a blank space before or after the forward slash symbol when using it in this way.

Abbreviations are shortened forms of words. Forwards slashes are often used when an abbreviation involves shortening two words or a compound word. A number of common abbreviations incorporate slashes. Reserve this usage only for very informal writing.

• care of (c/o) - Look out for the package we sent you c/o Jane Smith.
• with you (w/you) - Remember to take your notebook w/you when you leave today.
• without (w/o) - I don't want to go w/o you.
• air conditioning (a/c) - The house was unbearably hot as the a/c was broken.
• input-output (i/o) - Choose a computer with a powerful processor to ensure seamless processing of all i/o functions.
  

Did you notice that each of these examples has an air of informality? You'd never write "w/you" in an academic paper. However, in less formal settings, forward slashes help us shorten our writing. Don't leave a space on either side of the slash.

Forward slashes are used in a few situations that involve numbers. Specifically, they can be used to write dates, as well as to express ratios or fractions.

When writing a date, you can opt to use a combination of words and numbers, such as December 25, 2025. You can also leave out the words entirely. When writing dates with only numbers, you'll need to use forward slashes.

• month, day and year - 12/25/2025 or 12/25/25
• month and day only - 12/25
  

Even though slashes are usually used informally, it can be appropriate to use a forward slash when dealing with dates even in formal writing. Do not leave spaces between the slashes and the numbers. Be mindful of any special requirements that apply to what you are writing. For example, the military format for dates doesn't allow for any symbols to be used. Some citation methods might prefer a hyphen (12-25-2025). It's always worth the extra ounce of effort to check and double-check your teacher's preferred method of citation.

Slashes can be used when you are writing ratios or fractions in numeric form.

• one-fourth - 1/4
• three fifths - 3/5
  
• two to five ratio - 2/5
• 1:3 ratio - 1/3

Would you write "1/4 of the population is happy," or "one-fourth of the population is happy"? Apply the rules for writing numbers when deciding whether to spell out ratios or fractions or to use numerals.

Writers commonly use forward slashes to separate lines when quoting poems or songs. Poets and songwriters themselves don't tend to use slashes in their work. However, when their work is referred to in text, a slash is used to transition from one line to the next.

• "Somehow we do it/ Somehow we've weathered and witnessed/ a nation that isn’t broken/ but simply unfinished/"- from Amanda Gorman's The Hill We Climb
• "Amazing grace/ How sweet the sound/ That saved a wretch like me/ I once was lost, but now I'm found/ Was blind, but now I see/" - from John Newton's Amazing Grace
• "My mistress' eyes are nothing like the sun;/ Coral is far more red than her lips' red;/ If snow be white, why then her breasts are dun;/ If hairs be wires, black wires grow on her head./" - from Shakespeare's "Sonnet 130"
• "Fancy unto fancy, thinking what this ominous bird of yore—/ What this grim, ungainly, ghastly, gaunt, and ominous bird of yore/ Meant in croaking 'Nevermore./" - from Edgar Allan Poe's "The Raven"

The rule for spacing is different when using slashes in this way. Place the forward slash at the end of a line of poetry or a song, then leave a blank space before the first word of the next line.

Forward slashes are also used in phonetics to indicate differences between how letters are pronounced. They are used to indicate a phoneme. Any time you see a letter, or a group of letters, within two slash marks, that indicates that you are viewing a sound-based (phonemic pronunciation) pronunciation.

• /k/ is a phoneme, which refers to the sound of the "k" in kite, the sound of the "c" in cat and the last syllable of the word antique.
• /sh/ is the phoneme for the first sound made in the words chef and shell, as well as the beginning of the second syllable in lotion.
• /skaɪ.lɚ/ is the phonemic pronunciation of the name Schuyler, based on the International Phonetic Alphabet (IPA)

Backslashes and vertical slashes are rarely used in writing, though it's a good idea to know what they mean in case you come across these symbols.

• The backslash (\) can perform numerous functions in computer code, varying in meaning based on the programming language. For example, it can be used to indicate the end of a line of code, to stand for a decimal exponent, or be paired with an alphanumeric character to execute certain commands.
• In computer programming, a vertical slash (|) is an "or" operator. When a developer writes a line of code, this symbol indicates that the software should do one thing or the other. In C++, for example, the code if (x == 'a' || x == 'b') is telling the program to determine if "x" is equal to either "a" or "b."
• In math, the vertical slash (|) can be used several ways. For example, when placed on both sides of a variable, it means absolute value (|x| means the absolute value of "x"). It can also indicate conditional probability (Writing P(a|b) means the probability of "a," such that "b" is true).

Before you can use the slash keys, you'll need to be able to locate them on your computer keyboards.

• backslash - The backslash appears on the row of keys immediately below the numbers. It is above the enter key.
• vertical slash - The vertical slash (|) is on the same key as the backslash. You'll need to press the shift key with it.
  
• forward slash - The forward slash (/ ) is on the bottom row of a computer keyboard, between the period (.) key and the shift key.

And there you have it! The forward slash may not be the most common form of punctuation, but it's certainly multi-faceted. You're most likely to see it used in dates, "and/or" situations or very informal documents. As long as you're not writing a formal academic paper or business document, you can feel free to employ a forward slash from time to time. That's the beauty of the English language! Writers can spice it up in so many ways, including the illustrative virgule. Now that you have mastered slashes, expand your punctuation expertise to include how to use colons, semicolons and dashes.