Boundary Value Analysis Generator
Off-by-one bugs live at the edges. Enter a valid range and this tool generates the boundary value analysis and equivalence partitioning test cases, valid and invalid values with notes, ready to drop into a test plan. Free, client-side, no account.
Generate boundary and partition test values.
Enter a valid range and get the boundary value analysis and equivalence partition test cases instantly, the exact values an interviewer expects you to name. Nothing is uploaded.
Two techniques, used together
Equivalence Partitioning
Group inputs into classes that should behave the same, below the range, within it, above it, and test one representative from each. It cuts redundant cases without losing coverage.
Boundary Value Analysis
Test the edges between those classes: just below min, min, just above min, and the same around max. Defects cluster at boundaries because of off-by-one and wrong comparison operators.
Why the edges
A < that should be a <=, an inclusive bound treated as exclusive, a length check that misfires at exactly the limit, these almost never show up in the middle of a range, only at its edges.
Pick the right step
The step is the smallest meaningful increment: 1 for integers, 0.01 for currency. It defines what "just below" and "just above" a boundary actually are.
Questions before you start
What is boundary value analysis?
Boundary value analysis (BVA) is a test design technique that targets the edges of an input range, where defects cluster. For a valid range you test just below the minimum (invalid), the minimum, just above the minimum, just below the maximum, the maximum, and just above the maximum (invalid).
What is the difference between BVA and equivalence partitioning?
Equivalence partitioning divides inputs into classes that behave the same (below range, within range, above range) and tests one representative per class. Boundary value analysis then tests the edges between those classes, where off-by-one and comparison bugs hide. They are complementary.
Is this tool free?
Yes. It runs entirely in your browser, no account, no payment, no upload. Copy the generated cases as a Markdown table or download them.
Does it handle decimals and currency?
Yes. Set the step to the smallest meaningful increment, for example 0.01 for currency, and the just-below and just-above boundary values are calculated at that precision.
Keep going
Boundary Value Analysis (glossary)
The definition, why edges fail, and how to discuss BVA in an interview.
Equivalence Partitioning (glossary)
How to split inputs into classes and pick representatives without losing coverage.
QA Methodology Questions
Practice test-design questions on BVA, equivalence partitioning, and test strategy.
QA Mock Interview Practice
Explain your test-design choices out loud with an AI interviewer. Scored, free to start.