Boundary Value Analysis (BVA) is one of the simplest and most effective testing techniques used to find defects that often occur at the edges of input ranges. Many real world bugs appear when the system handles minimum, maximum, or just inside values incorrectly. BVA helps testers focus on these critical points.
What Is Boundary Value Analysis?
Boundary Value Analysis is a technique where test cases are created using the boundary values of input fields instead of testing every possible number or combination. Because users often interact with limits like minimum age, maximum quantity, or smallest allowed price errors are more likely to occur at these boundaries.
Why Boundaries Matter
Most systems behave differently when:
Input is just below the valid range
Input is at the valid range
Input is just above the valid range
For example, if an age field allows values 18 to 60, common defects may appear at:17, 18, 60, 61
So instead of testing many random numbers, testing these boundary points is more efficient and effective.
Example: Age Input Field
Requirement: User age must be between 18 and 60 (inclusive).
Boundary values to test:
| Test case | Value | Expected result |
|---|
| Below lower boundary | 17 | Should reject |
| At lower boundary | 18 | Should accept |
| Just inside lower boundary | 19 | Should accept |
| Just inside upper boundary | 59 | Should accept |
| At upper boundary | 60 | Should accept |
| Above upper boundary | 61 | Should reject |
With only six tests, you cover the most risky areas.
Benefits of boundary value analysis
Reduces number of test cases while keeping coverage high
Catches defects early
Very simple to apply
Works for any system with numeric or measurable input limits
Helps ensure the system handles edge cases properly
Where to use boundary value analysis
We can apply Boundary Value Analysis in areas like:
Any input with a defined minimum and maximum is a good candidate.
Conclusion
Boundary Value Analysis is a powerful yet simple testing technique that improves test coverage and reduces effort. By focusing on the values at and around boundaries, testers can quickly uncover defects that often go unnoticed with random testing. It’s one of the foundational techniques every tester should know.