Sum Calculator
Instantly add numbers and find the total, count, and average. Supports commas, spaces, and new line inputs.
Enter Numbers
Sum (Total)
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Count
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Average
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Instantly add numbers and find the total, count, and average. Supports commas, spaces, and new line inputs.
The Sum Calculator instantly adds any list of numbers and returns the total, along with the count, average, and number of ignored inputs. It's ideal for quickly totaling budgets, scores, measurements, or any list of values without needing a spreadsheet. To find the arithmetic mean of your data, use the Average Calculator.
Sum = a₁ + a₂ + a₃ + ... + aₙ In sigma notation: Σaᵢ (for i = 1 to n)
Each of these shows the running total, plus the count and average the calculator reports alongside it:
Example 1 — Monthly expenses 1450 + 975 + 540 + 260 + 180 = 2425 + 540 + 260 + 180 = 2965 + 260 + 180 = 3225 + 180 = 3,405 (count = 5, average = 681) Example 2 — Decimal measurements 12.5 + 7.25 + 4.3 + 9.95 = 19.75 + 4.3 + 9.95 = 24.05 + 9.95 = 34 (count = 4, average = 8.5) Example 3 — Hours worked, with a mix of formats 8, 7.5 8 6 9 = 38.5 (count = 5, average = 7.7)
Notice in Example 3 that commas, spaces, and line breaks were mixed in a single input — the calculator parses them all and still returns the correct total.
For consecutive integers from 1 to n, there's a well-known shortcut formula, said to have been discovered by mathematician Carl Friedrich Gauss as a schoolboy:
Sum (1 to n) = n × (n + 1) ÷ 2 Example: Sum of 1 to 100 = 100 × 101 ÷ 2 = 5,050 Example: Sum of 1 to 50 = 50 × 51 ÷ 2 = 1,275
The trick works because you can pair the first and last numbers (1 + 100 = 101), the second and second-to-last (2 + 99 = 101), and so on — giving 50 pairs that each total 101.
A few common running totals you may want to check at a glance:
| Series | Pattern | Sum |
|---|---|---|
| 1 to 10 | 1 + 2 + … + 10 | 55 |
| 1 to 50 | n(n+1)/2 | 1,275 |
| 1 to 100 | n(n+1)/2 | 5,050 |
| First 10 odd numbers | 1 + 3 + … + 19 = n² | 100 |
| Even numbers 2 to 100 | 2 + 4 + … + 100 | 2,550 |
Sum (Σ) uses addition; product (Π) uses multiplication. The sum of 2, 3, and 4 is 2 + 3 + 4 = 9. The product is 2 × 3 × 4 = 24. This calculator computes sums only.
5, 10, 15, 205 10 15 20Add all the numbers together. For example, 5 + 10 + 15 + 20 = 50. The Sum Calculator does this instantly for any list you provide, no matter the size.
The sum of all integers from 1 to 100 is 5,050. This follows the Gauss formula: n × (n + 1) ÷ 2 = 100 × 101 ÷ 2 = 5,050.
Sum is the result of adding numbers (e.g., 2 + 3 + 4 = 9). Product is the result of multiplying them (e.g., 2 × 3 × 4 = 24). This calculator computes sums only.
Σ (uppercase sigma) is the mathematical symbol for summation — it means 'add up all values in this series.' For example, Σ(i=1 to 4) i means 1 + 2 + 3 + 4 = 10.
Yes. The Sum Calculator fully supports negative values (e.g., -4.5) and decimals (e.g., 7.25). They are included in the total just like any other number.
Numbers can be separated by commas, spaces, or line breaks — for example '5, 10, 15' or one number per line. Mixed formats in the same input are handled automatically.
In addition to the total sum, it shows the count of valid numbers, the arithmetic average, and how many invalid inputs were ignored.
In everyday contexts, 'sum' and 'total' mean the same thing — the result of adding all numbers together. In formal mathematics, 'sum' specifically refers to addition, while 'total' is more general.
Copy the column and paste it straight into the input box. Each value lands on its own line, which the calculator reads automatically — no need to add commas. It then returns the total, the count of values, and the average in one step, so you can verify a spreadsheet SUM without re-typing anything.
The average (arithmetic mean) is the sum divided by the count of valid numbers. For 88, 92, 76, 95, and 84, the sum is 435 and the count is 5, so the average is 435 ÷ 5 = 87. The calculator shows both figures at once.
Non-numeric entries — like stray words, currency symbols, or empty cells — are skipped and reported in the 'Ignored' count. This lets you paste messy real-world data without it breaking the total; only the valid numbers are added.
The sum of the first n even numbers (2 + 4 + 6 + …) equals n × (n + 1). For example, the even numbers from 2 to 100 are the first 50 even numbers, so their sum is 50 × 51 = 2,550. The sum of the first n odd numbers is even simpler: it equals n² (1 + 3 + 5 + 7 = 16 = 4²).
No. Addition is commutative, meaning 5 + 10 + 15 gives the same total as 15 + 5 + 10. You can paste numbers in any order and the sum, count, and average will be identical.