OhMyCalc

Summation Calculator

Calculate the sum of all integers from a to b using the Gauss summation formula. Instant result for any range.

How to Use the Summation Calculator

  1. Enter the starting integer a.
  2. Enter the ending integer b (b ≥ a).
  3. Click Calculate to see the sum, count, and average.

Référence rapide

DeVers
Σ(1…10)55
Σ(1…100)5,050
Σ(1…1000)500,500
Σ(50…100)3,825
Σ(1…1,000,000)500,000,500,000

Cas d'utilisation

Formule

Σ(i, a, b) = (b − a + 1) × (a + b) / 2. This closed-form formula gives O(1) performance for any range.

Questions fréquemment posées

What does this calculator compute?
It computes the sum of all integers from your start value to your end value: a + (a+1) + … + b.
Why is it so fast?
It uses the Gauss closed-form formula instead of iterating through every number.
Can I sum non-integers?
This calculator sums integers only. Values are rounded down to whole numbers.