Ever seen the ± symbol in a math problem, a spec sheet, or a scientific report and wondered exactly what it means? You are not alone.
This small symbol carries a big meaning, and using it wrong can confuse your readers.
This guide explains what the plus or minus symbol means, where it comes from, and how to use it correctly in math, science, and everyday writing. By the end, you will type and read it with full confidence.
Quick Answer
The plus or minus symbol (±) shows that a value can be either higher or lower than a stated number. It combines the plus sign and minus sign into one character to express a range or margin of error.
For example, “10 ± 2” means the actual value could be anywhere between 8 and 12.
Correct Example
- “The temperature is 25°C ± 1°C.”
- “x = 5 ± 3”
Incorrect Example
- “The temperature is 25°C +/- 1°C.” (informal, avoid in formal writing)
- “x = 5 -+ 3” (wrong symbol order)
What Does the Plus or Minus Symbol Mean?
This symbol has a few related but distinct uses depending on the field.
Common Meanings
In math, ± shows two possible solutions to an equation. In science, it represents a margin of error or uncertainty in a measurement. In statistics, it shows a confidence interval around an average.
Simple Usage Examples
- Math: “x² = 9, so x = ±3” (meaning x = 3 or x = -3)
- Science: “The mass was measured at 5.2g ± 0.1g.”
- Statistics: “The survey result was 62% ± 3%.”
The Origin of the Plus or Minus Symbol
This symbol has a long history rooted in mathematical notation.
Word History
The ± symbol emerged from early mathematical shorthand used to combine both plus and minus operations in a single expression. It became standardized in scientific and mathematical texts to save space and reduce ambiguity when a value had two possible outcomes.
Why the Confusion Happens
People often confuse ± with the separate plus (+) and minus (−) signs, or type it incorrectly as “+/-” because the actual ± character is not always easy to find on a standard keyboard.
Formal Symbol vs Keyboard Shortcut Style
There is a difference between the true mathematical symbol and the informal text version many people type.
Comparison Table
| Style | Symbol | Where Used |
|---|---|---|
| Formal | ± | Math, science, engineering documents |
| Informal | +/- | Casual writing, emails, texts |
| Informal | +- | Rare, considered incorrect |
Plus or Minus vs Other Related Symbols
Several similar-looking symbols are often mixed up with ±.
Spelling/Symbol Comparison Table
| Correct Symbol | Common Mistake | Usage | Field |
|---|---|---|---|
| ± | +/- | Margin of error, dual solution | Math, Science |
| ∓ | ±(reversed) | Minus-plus, opposite order | Advanced Math |
| ≈ | ~ | Approximately equal | Math |
| ° | deg | Degree symbol | Science |
Which Style Should You Use?
Choosing between the formal symbol and the typed shortcut depends on your audience and platform.
US Audience
American academic and technical writing expects the true ± symbol in formal documents.
UK Audience
British scientific journals follow the same standard, using ± in formal contexts and reserving “+/-” for casual notes.
International Writing
Since ± is a universal mathematical symbol, it works across languages without translation issues, making it ideal for global technical content.
Academic Writing
Research papers, lab reports, and theses should always use the actual ± symbol, not “+/-“, to meet formatting standards.
Social Media Usage
On social media and in casual chats, “+/-” is widely accepted since typing the true symbol can be inconvenient on some devices.
Common Mistakes with the Plus or Minus Symbol
Even experienced writers get this symbol wrong in specific ways.
Frequent Errors
- Typing “+-” instead of “+/-” or “±”.
- Using ± when only addition is meant.
- Forgetting to explain what the margin represents (error, range, or solution).
- Mixing up ± with the similar-looking ∓ symbol.
Corrected Examples
- Wrong: “Result: 10+-2” → Right: “Result: 10 ± 2”
- Wrong: “x = 5, +3” → Right: “x = 5 ± 3”
Plus or Minus Symbol in Everyday Examples
This symbol shows up more often than most people realize.
Emails
“Please confirm the delivery window: 3 ± 1 business days.”
Social Media
“Poll results: 45% ± 2% margin of error.”
News Writing
“The survey found support at 52%, with a margin of error of ±3 points.”
School Writing
“Solve for x: x² − 16 = 0, giving x = ±4.”
Business Writing
“Projected revenue growth is 8% ± 1.5% for the next quarter.”
Google Trends & Usage Data
Interest in “plus or minus symbol” spans students, professionals, and anyone typing technical or scientific content.
Popular Countries
- United States
- United Kingdom
- Canada
- Australia
- India
Why People Search This Keyword
Most searches come from students solving equations, professionals typing reports with error margins, and writers who need to know how to insert the ± symbol correctly on a keyboard or in software like Word and Excel.
Related Grammar and Symbol Rules
Other math and text symbols cause similar confusion and are worth knowing.
Similar Symbol Mistakes
- Multiplication sign (×) vs letter x
- Division sign (÷) vs forward slash (/)
- Degree symbol (°) vs superscript zero
- Approximately equal (≈) vs equals (=)
Helpful Tips
On Windows, type ± using Alt+0177. On Mac, use Option+Shift+= . In Word, you can also insert it through the Symbol menu or type 00B1 followed by Alt+X.
FAQs
What does the plus or minus symbol mean?
It means a value can be higher or lower than the stated number by a certain amount, showing a range or margin of error.
How do you type the plus or minus symbol?
On Windows, press Alt+0177. On Mac, press Option+Shift+=. In Word, insert it via the Symbol menu.
Is “+/-” the same as “±”?
They mean the same thing, but “±” is the formal symbol used in academic and technical writing, while “+/-” is an informal typed substitute.
What is the plus or minus symbol called?
It is called the “plus-minus sign” or “plus or minus symbol.”
When do you use ± in math?
You use it when an equation has two possible solutions, such as square roots, or to show a range of acceptable values.
What does ± mean in statistics?
In statistics, ± shows the margin of error or confidence interval around a reported value.
Can I use +/- instead of ± in a research paper?
No. Formal academic writing requires the actual ± symbol, not the typed “+/-” version.
What is the opposite of the plus or minus symbol?
The symbol ∓, called “minus-plus,” reverses the order and is used in advanced mathematical expressions.
Conclusion
The plus or minus symbol (±) shows a range between two possible values, used widely in math, science, and statistics.
Use the true ± symbol in formal and academic writing, and reserve “+/-” for casual text. The most common mistake is typing it incorrectly or confusing it with similar symbols.
Once you know the shortcut keys and correct context, using ± becomes second nature.
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- Stationary or Stationery? One Vowel Changes Everything
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Hi, I am Anne Seaton. I am a writer and educator working with Wordssensei.com to help students learn English easily.
