Slash vs Backslash: A Grammar Guide

Not all punctuation marks have a long list of nicknames. Stroke, virgule, diagonal, right-leaning stroke, oblique dash, solidus, slant, separatrix, forward slash—all can be used for the slash.

And there’s the backslash. No nickname required. Unless you prefer to say backslant, slosh or reverse slash.

Laundry list of names aside, you’re here because you need answers. What’s the difference between the slash and the backslash? How do you use the slash correctly in a sentence? And is there a way to use the backslash correctly in a sentence?

Let’s take a look.

Slash vs Backslash

Let’s get the obvious difference out of the way. Slash—sometimes referred to as forward slash—slants right (or forward) while backslash slants left (or backwards).

Easy enough.

The biggest difference between slashes and backslashes—at least when it comes to English grammar—is that the slash is a punctuation mark in the English language while the backslash is not.

Most of this blog post will cover how to use the slash correctly in a sentence, from syntax and mathematics to abbreviations and shorthand.

Slashes in URLs

IRL, we’re familiar with the slash from its use in website addresses. The slash separates parts of the URL as folders do in a filing cabinet. Here’s my self-promoting example:

https://klwightman.com/category/grammar/

The main folder is KLWightman (named after me), then there’s a subfolder called Category where all my sub-sub-folders of blog post categories live. This URL takes you to the sub-sub-folder of grammar blog posts.

You’re welcome.

Slashes in File Names

The slash can also be found in digital file names on certain devices, such as Mac products. Like URLs, these slashes separate folders from sub-folders to locate the specific file that you want, such as:

/Users/mac/kaitlyn/grammar/slash.jpg

Slashes Substituting “Or”

You can use the slash correctly in a sentence when you want to indicate an alternative. A slash acts like shorthand for or that’s accepted in both formal and informal instances:

Dear Sir/Madam

It is company policy for each employee to supply his/her own pens.

Have you tried pressing the Refresh/Reload button on your browser?

Harold will buy chips and/or dip.

In all of these instances, the slash acts like the word or. Dear sir or madam. It is company policy for each employee to supply his or her own pens. Have you tried pressing the Refresh or Reload button on your browser? Harold will buy chips and dip, or Harold will buy chips, or Harold will buy dip.

Be mindful on how often you use the slash to signify or in your writing. Too many uses of it suggests laziness on the writer’s part. And no one wants to appear to be a lazy writer.

Slashes Substituting “As Well As”

This one’s used as much verbally as it is written. You can use the slash correctly in a sentence to denote as well as. When spoken, we say the word slash to make it clear that we’re using it.

Their apartment was so small that we hung out in their living room/bedroom.

Olive’s official title at the company is copywriter/HR specialist.

Slashes as Abbreviations

As writers, we love to abbreviate whenever we can without appearing lazy. And there are certain instances where a slash is not seen as shorthand but rather as the norm.

You can use a slash correctly in a sentence in specific instances where an abbreviation is accepted, such as:

Big Box Store, c/o Accounting Department (care of)

n/a (not applicable, not available)

w/o (without)

Slashes in Quoting Poetry

When writing an essay that follows MLA format, you can use a slash correctly in a sentence when reference a short passage of poetry. The slash is used to indicate line breaks in the poem while the double slash (//)—that’s two slashes—can be used to indicate a stanza break.

Here’s what I mean:

A strong instance of foreshadowing can be found in Shel Silverstein’s poem “Snowball.” The reader can surmise the snowball’s fate within the third and fourth lines of the poem: “I thought I’d keep it as a pet / And let it sleep with me.”

Slashes in Fractions

Let’s talk numbers. Or rather, parts of them.

Fractions use the slash to specify how much of a whole number, such as:

1/4 (one-fourth)

2/3 (two-thirds)

11/12 (eleven-twelfths)

Slashes in Measurement

The slash can also be used correctly in a sentence as a substitute for per. When gauging distance, speed and prices, the slash lets a writer abbreviate a unit of measurement like in the following examples:

The speed limit is 70 km/h (kilometres per hour)

The store sells donuts for $15/dozen ($15 per dozen)

Susan can type at 65 w/m (words per minute)

Slashes in Dates

Dates often rely on slashes to convey a specific time of year. You can use a slash correctly in a sentence to separate year from month from day.

My credit card expires 11/26 (November 2026)

Percy Jones was born on 14/12/1979 (14^th December 1979 in British English)

Darcy and William married on 12/14/1979 (December 14, 1979 in American English)

How to Use the Backslash Correctly

When it comes to English grammar, you don’t have to worry about how to use the backslash correctly in a sentence. Why? Because there’s no instance currently where a backslash is needed to properly punctuate a sentence.

But we’re all still curious about the backslash.

The backslash is important in other languages: C, Perl, PHP, Python. In short, programming languages.

I’ll leave that explanation up to the tech professionals.

If you are a Windows computer user (past or present), you have also seen the backslash used in file name paths:

C:\Users\Win\Files\backslash.doc

Did I miss one? What’s another way you can use a slash correctly in a sentence? Share your instance in the comment section below.