Simple Calculator Online: Free Basic Calculator

This free simple calculator online handles standard daily arithmetic, percentage calculations, order of operations, and basic expression evaluation directly in your web browser. Also, you can click the buttons or type using your keyboard to solve additions, subtractions, multiplications, divisions, and percentages instantly without installing software or signing up for an account.

Need a quick answer? This free simple calculator handles everyday arithmetic, brackets and percentages, and keeps a history of your recent calculations. Also, tap the keys or type with your keyboard; the answer appears as you type.

How to use this simple calculator online

Performing calculations with this tool is straightforward whether you prefer using a physical desktop keyboard or tapping on a touchscreen mobile device.

• Type or tap numbers and basic operations: Use the on-screen buttons or your keyboard for addition (+), subtraction (-), multiplication (* or ×), and division (/ or ÷).
• Evaluate expressions: Press = or hit Enter on your keyboard to complete a calculation. Continuing to type an operation right after pressing Enter automatically carries forward your previous result.
• Correct mistakes: Press ⌫ (or Backspace on your keyboard) to delete the last character entered. Press AC (or Escape/C on your keyboard) to clear the entire entry display.
• Use calculation history: The history tape below the input keys logs your last 10 calculations. Tap or click any previous result entry to re-insert that number into your active calculation.
• Group operations and use percentages: You can place brackets ( ) and percentage symbols % anywhere within a numerical expression to control the exact order of operations.

Keyboard shortcuts guide

Using physical keyboard shortcuts allows you to complete fast calculations without moving your mouse cursor:

• Numbers (0–9) and Decimal (.): Type directly using standard keys or the numpad.
• Addition (+): Press + or Shift + =.
• Subtraction (-): Press –.
• Multiplication (×): Press * (Shift + 8).
• Division (÷): Press /.
• Parentheses (): Press Shift + 9 for ( and Shift + 0 for ).
• Percentage (%): Press Shift + 5.
• Calculate Result (=): Press Enter or =.
• Clear Display (AC): Press Escape or C.
• Backspace (⌫): Press Backspace or Delete.

Order of operations (PEMDAS and BODMAS explained)

This simple online calculator follows the standard order of operations, commonly abbreviated as PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction) or BODMAS (Brackets, Orders, Division and Multiplication, Addition and Subtraction).

Common order of operations pitfalls

Two details trip people up most often when evaluating mathematical expressions:

Multiplication does not come before division. In both PEMDAS and BODMAS, multiplication and division hold equal priority. They are executed from left to right. This rule applies to addition and subtraction. For example, 12 ÷ 3 × 2 is 4 × 2 = 8. A simple online calculator will not evaluate it as 12 ÷ 6 = 2.

Ambiguous expressions need explicit brackets. Puzzles like 6 ÷ 2(1 + 2) circulate online. People read them differently. This simple calculator treats implied multiplication like a standard sign. It works left to right, giving an answer of 9. If you meant 6 ÷ (2(1 + 2)) = 1, type the extra outer brackets. When in doubt, bracket the part you want done first. Brackets always win.

A handy habit is to estimate before you evaluate an expression. For 3 × (4 + 6) ÷ 5, think “4 plus 6 is 10, 3 times 10 is 30, and a fifth of 30 is 6.” If the display of your online calculator shows something very different, look for a missing or misplaced bracket.

How to calculate percentages on a basic calculator

The % key simplifies working with proportions, tips, sales tax, discounts, and percentage differences.

• 15% of 80: 80 × 15% = 12 (or 80 × 0.15 = 12).
• Add 15% (tip or tax) to 80: 80 + 15% = 92 (or 80 × 1.15 = 92).
• Take 15% off 80 (a discount): 80 – 15% = 68 (or 80 × 0.85 = 68).
• What percent is 12 of 48? 12 ÷ 48 × 100 = 25%.
• Percentage change from 48 to 60: (60 − 48) ÷ 48 × 100 = 25% increase.

Adding or taking off a percentage: 80 + 15%

Typing 80 + 15% gives 92. And 80 – 15% gives 68. Our simple online calculator treats percentages as of that amount. This is like phone and store calculators. You can chain them. For example, 200 – 10% – 10% = 162. Each discount applies to the new total. Elsewhere, % means “divide by 100”. So, 80 × 15% = 12.

What was the original price before a discount? If an item costs 60 after a 20% discount, divide by the remaining fraction: 60 ÷ 0.8 = 75. With the % key, typing 60 ÷ 80% also gives 75.

The same idea removes sales tax. For example, to find the pre-tax price of an item that costs 54 including 8% sales tax, type 54 ÷ 1.08 = 50.

Percent changes do not simply add

• Up 25%, then down 25% does not bring you back to the starting point. Starting from 100: 100 × 125% × 75% = 93.75.
• Two discounts of 20% and 10% are not equal to 30% off. For example, starting from 100: 100 × 80% × 90% = 72, which is an effective discount of 28%.
• Direction matters for percentage change. From 48 to 60 is a 25% increase, but from 60 back to 48 is a 20% decrease: (60 − 48) ÷ 60 × 100 = 20%. The base divisor is always the starting value.

Everyday calculation examples

Here are ten common everyday tasks solved step by step on a basic calculator:

1. Splitting rent: Dividing $1,250 among 4 flatmates: 1250 ÷ 4 = 312.50 each.
2. Tip at 18% on a bill of 45.60: 45.60 × 18% ≈ 8.21 (total bill with tip is 45.60 + 8.21 = 53.81).
3. Test score percentage: 18 out of 24 is 18 ÷ 24 × 100 = 75%.
4. Best value at the store: 12 eggs for 4.20 cost 4.20 ÷ 12 = 0.35 each; 18 eggs for 5.85 cost 5.85 ÷ 18 = 0.325 each, so the 18-egg pack is cheaper per egg.
5. Fuel economy: 350 miles on 14 gallons is 350 ÷ 14 = 25 miles per gallon.
6. Average of test scores: Averaging grades 82, 90, and 77: (82 + 90 + 77) ÷ 3 = 83. However, the brackets matter; without them you would divide only the 77 by 3.
7. Weighted grade calculation: Two tests counting 30% each and a final counting 40%, with scores of 82, 90, and 77: 82 × 30% + 90 × 30% + 77 × 40% = 82.4.
8. Pay for part of a shift: 2.5 hours at 18.50 per hour is 2.5 × 18.50 = 46.25.
9. Scaling a recipe by 1.5: 3/4 cup (0.75) of flour becomes 0.75 × 1.5 = 1.125 cups (1 and 1/8 cups).
10. Compound savings growth: $1,000 at 5% interest per year for 3 years is 1000 × 105% × 105% × 105% ≈ 1157.63. As a result, each year’s growth applies to the updated balance.

For longer stretches of compound growth, the exponential growth calculator does the repeated multiplication for you, and the geometric series formula adds up regular deposits.

Why 0.1 + 0.2 sometimes looks odd and dividing by zero

Computers store decimals in binary, so 0.1 + 0.2 equals 0.30000000000000004 inside the machine’s memory. This calculator automatically rounds results to 12 significant digits, so it displays the exact answer you expect: 0.3.

When performing division, dividing any number by zero (such as 7 ÷ 0) is mathematically undefined. The calculator shows an Error display instead of producing misleading numbers. Press AC to clear the error state.

Comparing basic online calculators with advanced math tools

Depending on the problem you are solving, choosing between a basic, scientific, or graphing calculator ensures you have the right tool for the job.

Use the scientific calculator for square roots, powers, trig, and logarithms. To plot a formula across many inputs, use the graphing calculator. For continuous averages, like temperature, use the average value of a function. Try our step-by-step solver for algebra and calculus with full working. You can also browse our calculus concepts guide. This online calculator is more than a simple tool.

Practice problems

1. Evaluate: 7 + 8 × 2
2. Find 20% of 350.
3. Evaluate: (15 - 3) ÷ 4
4. Evaluate: 12 ÷ 3 × 2
5. A price is $40 after a 20% discount. What was the original price?
6. 200 is reduced by 10% twice. What is the result?

Answers:

1. 23 (Multiply first: 8 × 2 = 16, then add 7).
2. 70 (350 × 0.20 = 70).
3. 3 (Evaluate inside brackets first: 15 – 3 = 12, then 12 ÷ 4 = 3).
4. 8 (Work left to right: 12 ÷ 3 = 4, then 4 × 2 = 8).
5. 50 (Divide final price by remaining percent: 40 ÷ 0.8 = 50).
6. 162 (200 × 90% × 90% = 162, since successive discounts apply to the new lower totals).

Frequently asked questions

Is this calculator free?

Yes. It runs directly in your browser with no sign-up or software installation required, and nothing you type is sent to an external server.

Does it work on phone and tablet touchscreens?

Yes. The keys are sized for touch displays, and on mobile phones you can use the on-screen keypad directly.

How do I calculate a percentage of a number?

Multiply the number by the percentage value. For example, typing 350 × 20% or 350 × 0.2 both return 70.

How do I find the original price before a discount?

Divide the sale price by the percentage you actually paid. For example, for an item costing $60 after a 20% discount, typing 60 ÷ 80% or 60 ÷ 0.8 both return 75.

Why is 2 + 3 × 4 equal to 14 instead of 20?

Multiplication is evaluated before addition under standard order of operations, so 3 × 4 is evaluated first to give 12, plus 2 equals 14. Use brackets, (2 + 3) × 4, if you want addition solved first to get 20.

Further reading

• Order of operations (Wikipedia) — PEMDAS, BODMAS and the history of mathematical conventions.
• Percentage (Wikipedia) — Percentage change, ratios, base values, and percentage points.
• Floating-point arithmetic (Wikipedia) — Why binary computer storage produces floating-point representations like 0.30000000000000004.