Calculate continuous-interval overlap relative to A, B, the smaller interval or their union, or compare an entered overlap area with a reference area.

Continuous intervals use one shared coordinate unit; endpoint order is normalized. Area mode compares an entered overlap with one explicit reference area. These percentages use different denominators.

Related Calculators

Overlap Percentage Formula

In area mode, the following formula compares a given overlap area with an explicitly chosen reference area. Interval mode also reports several denominators; its union length is A + B − overlap, excluding any gap.

O = (Aₒ / Aₜ) × 100

Variables:

  • O is the overlap percentage
  • A_o is the overlap area
  • A_t is the chosen reference area (A, B or their union)

To calculate the overlap percentage, divide the overlap area by the total area and multiply the result by 100 to get the percentage.

What is Overlap Percentage?

Overlap percentage is a measure of how much one area overlaps with another area, expressed as a percentage of the total area. This metric is commonly used in various fields such as geography, biology, and computer science to quantify the degree of overlap between two regions or datasets. For example, in image processing, overlap percentage can be used to determine how much of one image overlaps with another, which can be useful for tasks like image registration and object detection.

How to Calculate Overlap Percentage?

For the area example below, choose Overlap area / reference area. For interval comparisons, choose Two continuous intervals and enter four endpoints in one coordinate unit; reversed endpoints are normalized and both ranges must have positive length.

  1. First, determine the overlap area (A_o).
  2. Next, determine the reference area (A_t) and choose the appropriate area units.
  3. Next, calculate the overlap percentage using the formula O = (A_o / A_t) * 100.
  4. Select Calculate to obtain the percentage; 50 / 200 × 100 = 25% for the example below.
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Overlap area (A_o) = 50

Total area (A_t) = 200