How to use the Boundary Value Analysis Calculator
- 1. Enter the rangeType the minimum and maximum valid values for the field.
- 2. Set the stepUse 1 for whole numbers, 0.01 for money, or your own step.
- 3. Pick a methodChoose 3-value or 2-value BVA and copy the values.
How boundary values are chosen
Developers often write > where they meant >=, so bugs cluster at the edges of ranges. Boundary value analysis tests just inside, on, and just outside each edge.
- 2-value BVA: min − step, min, max, max + step.
- 3-value BVA: min − step, min, min + step, max − step, max, max + step.
Worked example: an age field accepts 18 to 60 in whole years. 3-value BVA gives 17, 18, 19, 59, 60, 61. 17 and 61 must be rejected with a clear message; the other four must be accepted. The middle value, 39, is a good nominal happy-path test.
Tips for real forms
- Get the step right. A price field with two decimals needs 0.01, so a range 1.00–999.99 tests 0.99 and 1000.00.
- Test both ends of every range, including hidden ones such as maximum text length or upload size.
- Combine with equivalence partitioning to cover blank, non-numeric and wrong-type input.
- Dates have boundaries too: month ends, 29 February, time zones.
BVA is defined in the ISTQB Foundation syllabus; the 3-value form is also called full boundary testing. It assumes ordered input. For combinations of several conditions, use a decision table instead. Build the other half of the test set with the equivalence partitioning tool or map rules with the decision table generator.
Frequently asked questions
Which is better, 2-value or 3-value?
3-value catches more off-by-one errors and is common in interviews. 2-value is quicker when you have many fields.
What is the nominal value?
A normal value from the middle of the range, used as a basic positive test.
Is the Boundary Value Analysis Calculator free?
Yes, the Boundary Value Analysis Calculator is free. The first time you see your first result, you are asked for your name and WhatsApp number once. After that, this and every other Uncodemy tool opens straight away without the form.