Quick start
The calculator solves one step at a time. That keeps it fast and easy to check. If you need parentheses, powers, roots, or trigonometry, use the Scientific Calculator instead.
- Enter the first number using the on-screen keypad or your keyboard.
- Choose an operation: add, subtract, multiply, or divide.
- Enter the next number and press equals or Enter.
- Use Copy result if you want to paste the answer into notes, chat, or a form.
- Check Calculation History if you need to compare recent totals.
What each button does
AC clears the calculator and starts over from zero.
DEL removes the last digit, which helps when one number is mistyped.
% changes the current entry into a percentage. In plus or minus problems, it uses the first number as the base.
+/- switches the current number between positive and negative.
x multiplies two numbers.
/ divides one number by another.
How the percent key works
Percent is the button most people double-check. If you type 80 - 20%, the percent key turns 20 into 16 because 16 is 20 percent of 80. When you press equals, the calculator subtracts 16 and shows 64.
For a number by itself, percent is simpler. Typing 20% changes the display to 0.2. That is useful when you want to multiply by a rate yourself.
Keyboard shortcuts
Worked examples
60.75 total before tax
64 after the discount
42 each
Common mistakes to check
Do not type money symbols. Enter 48.50, not $48.50. The result can still mean dollars if that is what your number means.
Put the base number first for discounts. Use 80 - 20%, not 20 - 80%, when you want 20 percent off 80.
Do not expect hidden order of operations. This page solves the current step. Use the scientific calculator for full expressions.
Do not divide by zero. The calculator blocks it because division by zero is not a normal number.
Check very long decimals. The display rounds long answers so they stay readable.
Using history and copy
After a calculation finishes, the result is added to the history panel. This is useful when you are comparing totals, checking several discounts, or working through a few quick numbers in a row.
The Copy result button copies the current display value to your clipboard. The Clear history button clears only the visible history list; it does not change the current calculator result.
Sources and limits
This guide uses standard arithmetic and percent rules, plus the actual behavior of the Access Free Tools calculator. For math background, OpenStax explains percent as parts per 100, Khan Academy covers order of operations, and MDN documents the browser arithmetic operators used by JavaScript.
Useful references: OpenStax percent, Khan Academy order of operations, and MDN arithmetic operators.
Privacy note
The calculator runs in your browser. The recent calculation history is kept only on the page during the current session and is not sent to a server by this tool.