Average Calculator

Paste a list or add numbers one at a time

The Average tab is a list of rows. Type a number in a row, then press Add number for the next one, or paste a whole set into the box above the list and press Add to list. Commas, spaces, and new lines all count as separators, so a column copied from a spreadsheet lands as one number per row. A thousands comma stays with its number, so 1,000 is one thousand. In a row split by commas, such as 95,100,88, the commas separate the numbers. When a comma could go either way, as in 95,100, the note under the box says how it was read.

Add to list keeps any numbers you already typed, drops blank rows, and clears the paste box so the same set is not added twice. The trash icon removes one row. Clear list wipes the rows and puts three empty ones back. This average calculator updates the cards as you type.

Average, count, and sum

Three cards sit under the list on this average calculator. Average is the arithmetic mean: add the numbers, then divide by how many there are. Count is how many rows held a real number. Sum is that total before the division. Blank rows stay out of the count. A row with text that is not a number is skipped, outlined in red, and mentioned under the formula.

Try an example replaces the list with 86, 91, 78, and 88. The sum is 343, the count is 4, and the average is 343 divided by 4, which is 85.75. Use it to see the cards move, then Clear list and enter your own scores.

Weighted average

The Weighted average tab is for lists where some numbers count more than others. Each row has a value and a weight. A test that is half the grade gets a larger weight than a quiz that is a small slice of it. Add row gives you another pair. Add pairs reads the paste box, one pair per line, value then weight, split by a space, a comma, or a tab.

Each value is multiplied by its weight, those products are added, and the total is divided by the sum of the weights. Weights are relative, so 20 and 30 give the same result as 0.2 and 0.3. They can total 100 or any other amount. A trailing percent sign is read as the number in front of it, so a weight of 20% counts as 20. A row is used only when both boxes contain a number. If the weights you entered add up to zero, the card shows a dash, because there is nothing to divide by.

Switching tabs keeps the other list and clears the paste box. You can check a plain average, open Weighted average, and come back to the same numbers. Try an example on this tab replaces the rows with a homework score of 92 with weight 20, quizzes at 85 with weight 30, and a test at 78 with weight 50, which comes out to 82.9.

The formula under the result

The Formula box writes the calculation with your numbers in it. On the Average tab, 86, 91, 78, and 88 show up as Average = (86 + 91 + 78 + 88) / 4 = 343 / 4 = 85.75. On the Weighted average tab each pair is written as value × weight, the weights are added on their own, and those two totals are divided.

With more than eight numbers, the box stops listing every term and shows the totals, so a long paste stays on one line. The cards still use every number you entered. With the list still empty, the box shows the bare formula and tells you what to add.

Empty input, one number, and decimals

On a fresh page every row is blank, the three cards show a dash or a count of zero, and the formula tells you what to add. One number is a complete list: the count is 1, the sum is that number, and the average equals it, written as that number divided by 1.

Type decimals with a point, as in 15.5. Extra zeros are trimmed, so 1.5 and 2.5 average to 2. A repeating result keeps about 12 significant digits, so 2, 2, and 6 average to 3.33333333333. Negatives are allowed, and a minus sign is wrapped in parentheses inside the sum so it stays readable. The math runs in your browser. There is no account, and closing or reloading the page clears both lists.