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Trapezoid Midsegment Calculator.

Calculate the segment joining the midpoints of the legs.

On-device calculationNo signup
01

Set your values

Results update as you type.

Midsegment: 6.5

Midsegment

0.000000
baseA: 8

baseA

0.000000
baseB: 5

baseB

0.000000

Results update automatically as you type.

Use Cases

Geometry homework and exams

Quickly verify your manual calculations for trapezoid midsegment problems in math assignments or test prep.

Example: If base a = 10 cm and base b = 14 cm, the midsegment is 12 cm.

Design and construction planning

Use the midsegment to find the average width of a trapezoidal area, useful for estimating materials or dimensions.

Example: For a trapezoidal garden bed with bases 5 ft and 9 ft, the midsegment is 7 ft.

Frequently Asked Questions

What is the midsegment of a trapezoid?
The midsegment (also called the median) is a line segment that connects the midpoints of the non-parallel sides. It is parallel to the bases and its length is the average of the two bases.
How do you calculate the midsegment?
Add the lengths of the two parallel bases (base a and base b) and divide by 2. The formula is: Midsegment = (a + b) / 2.
Can the midsegment be longer than one of the bases?
Yes, the midsegment is always between the lengths of the two bases. If one base is longer, the midsegment will be longer than the shorter base but shorter than the longer base.

Tips & Common Mistakes

Tips

  • Ensure both base lengths are in the same unit before calculating.
  • The midsegment is simply the average of the two bases, so you can do it mentally for simple numbers.
  • Use this calculator to check your work when solving trapezoid area problems, as the midsegment is half the sum of bases.
  • If you have the midsegment and one base, you can find the other base by doubling the midsegment and subtracting the known base.

Common Mistakes to Avoid

  • Forgetting to divide by 2 after adding the bases.
  • Using the lengths of the non-parallel sides instead of the parallel bases.
  • Mixing up units (e.g., using inches for one base and feet for the other) without converting.

Last updated: August 13, 2026