Enter a score from 0 to 10 for each BASFI question (0 = easy, 10 = impossible). The calculator returns your average BASFI score.
What is the BASFI?
BASFI stands for Bath Ankylosing Spondylitis Functional Index. It is a widely used questionnaire that helps measure how much ankylosing spondylitis (AS) or axial spondyloarthritis affects day-to-day function. The score focuses on practical activities such as bending, climbing stairs, reaching, standing, and completing a full day.
Each item is scored from 0 to 10. A lower value means less difficulty; a higher value means greater difficulty. The final BASFI score is the average of all 10 responses, resulting in a number from 0 to 10.
How to use this BASFI calculator
- Rate each activity based on your experience over recent days.
- Use a number from 0 (easy/no problem) to 10 (impossible).
- Complete all 10 questions for the most reliable score.
- Track results over time to discuss trends with your rheumatology team.
Quick interpretation guide
| BASFI Average | General Interpretation |
|---|---|
| 0.0 – 2.0 | Low functional limitation |
| 2.1 – 4.0 | Mild limitation |
| 4.1 – 6.0 | Moderate limitation |
| 6.1 – 8.0 | High limitation |
| 8.1 – 10.0 | Very high limitation |
BASFI vs BASDAI: what is the difference?
BASFI measures function (what you can do), while BASDAI measures disease activity (symptoms such as fatigue, stiffness, and pain). Both are useful, but they answer different questions: one is about ability, the other is about symptom burden.
In routine care, clinicians often look at BASFI together with pain scores, spinal mobility findings, blood tests, and imaging. A single score is never the whole story.
Tips for tracking your progress
1) Be consistent with timing
Try to complete BASFI at similar times (for example once every 2 to 4 weeks). Consistency helps you and your doctor spot meaningful patterns.
2) Add context to your score
If your BASFI rises, write down possible reasons: poor sleep, illness flare, reduced exercise, or stress. Context improves clinical decision-making.
3) Focus on trends, not single points
Day-to-day variation is normal. A sustained rise over several measurements is usually more informative than one high score.
Important limitations
- BASFI is subjective and self-reported.
- Temporary factors (injury, infection, poor sleep) can affect results.
- The score does not diagnose ankylosing spondylitis.
- Interpretation should be individualized with professional guidance.
Bottom line
A BASFI calculator is a practical way to quantify function and monitor changes over time. Use it as a structured check-in tool, not a diagnosis tool. If your score is worsening, or if daily activities become significantly harder, discuss your results with your healthcare team promptly.