Software Testing - Boundary Value Analysis (BVA)

Boundary Value Analysis (BVA) is a software testing technique used to identify defects at the boundaries of input ranges.
Since errors often occur at the edges of input values, BVA helps testers focus on input values that lie:

  • At the minimum limit

  • Just below the limit

  • At the maximum limit

  • Just above the limit

It is one of the most commonly used black-box testing techniques.

What Is Boundary Value Analysis?

Boundary Value Analysis is based on the idea that software is more likely to have defects around the boundary conditions rather than in the middle of the input range.

For example, if an age field accepts values between 18 and 60, bugs are more likely when the user enters 17, 18, 60, or 61 than a value like 35.

Why Use Boundary Value Analysis?

  1. Finds defects where they are most common

  2. Reduces number of test cases while increasing coverage

  3. Simple and effective for numeric inputs

  4. Works well with any field having defined ranges

  5. Improves accuracy of validation testing

Key Principles of BVA

  • Test at edges of input ranges

  • Test just below, at, and just above boundaries

  • Applicable to integer, float, date, time, string length, etc.

  • Can be used alone or combined with Equivalence Partitioning

Typical Boundary Values to Test

For a range min → max, test:

  1. min - 1

  2. min

  3. min + 1

  4. max - 1

  5. max

  6. max + 1

BVA Example 1: Age Input Field

Requirement:

User age must be between 18 and 60.

Boundary Test Values:

  • 17 (below minimum)

  • 18 (minimum valid)

  • 19 (just above minimum)

  • 59 (just below maximum)

  • 60 (maximum valid)

  • 61 (above maximum)

BVA Example 2: Password Length

Requirement:

Password must be 8 to 16 characters long.

Boundary Test Values:

  • 7 characters → Invalid

  • 8 characters → Valid

  • 9 characters → Valid

  • 15 characters → Valid

  • 16 characters → Valid

  • 17 characters → Invalid

BVA Example 3: Date Range

Requirement:

Booking allowed only from 1st May to 31st May.

Test:

  • 30 April

  • 1 May

  • 2 May

  • 30 May

  • 31 May

  • 1 June

When to Use Boundary Value Analysis

  • When input has numeric limits

  • When field has a minimum or maximum length

  • When form accepts date or time ranges

  • When the system has range-based validations

Advantages of BVA

  • Extremely effective at catching edge-case bugs

  • Requires fewer test cases

  • Simple and easy to implement

  • High defect-finding rate

Limitations of BVA

  • Only works with ordered values (numbers, dates, lengths)

  • Not suitable for complex business logic

  • Might miss errors outside boundary-focused conditions