PBAC Score Calculator (Heavy Menstrual Bleeding Chart)
Score one period with the Pictorial Blood Loss Assessment Chart (PBAC): count lightly, moderately and fully soaked pads and tampons, clots and flooding to see if the score is 100 or more.
How it works
Pads: light 1, moderate 5, soaked 20 points · Tampons: light 1, moderate 5, soaked 10 · Small clot 1, large clot 5, flooding 5 · Score ≥ 100 ≈ blood loss > 80 ml (menorrhagia)
The Pictorial Blood Loss Assessment Chart (Higham, O’Brien and Shaw, 1990) turns a period diary into a number: each pad or tampon scores 1, 5 or 20 (tampons 10) depending on how soaked it is, plus points for clots and flooding. In the original validation a total of 100 or more identified blood loss above 80 ml — the classic definition of heavy menstrual bleeding — with about 86% sensitivity and specificity. NICE now defines heavy bleeding by its impact on your life rather than a number, so a lower score with troublesome symptoms still deserves a doctor’s visit.
Worked example
Over one period you used 4 lightly stained pads (4 × 1), 6 moderately soaked pads (6 × 5 = 30) and 3 completely soaked pads (3 × 20 = 60), and passed 2 small clots (2) and 1 large clot (5): 4 + 30 + 60 + 2 + 5 = 101, a PBAC score of 101 — heavy menstrual bleeding likely.
Sources: Higham JM, O’Brien PM, Shaw RW (1990) Assessment of menstrual blood loss using a pictorial chart. Br J Obstet Gynaecol 97:734–739 · NICE guideline NG88 (2018, updated 2021) Heavy menstrual bleeding: assessment and management
Frequently asked questions
What is a normal PBAC score?
A score under 100 for the whole period is generally considered within the normal range. A score of 100 or more suggests more than 80 ml of blood loss, the traditional threshold for heavy menstrual bleeding.
How do I fill in a PBAC chart?
Every time you change a pad or tampon, note how soaked it is (light, moderate or full) and record any clots or flooding. Add the points at the end of the period. Use the same brand throughout for consistency.
Does the PBAC work with menstrual cups or period underwear?
Not directly — it was validated for pads and tampons. With a menstrual cup you can measure volume: more than 80 ml per period is heavy. Bring your notes to your doctor either way.
What can cause heavy periods?
Fibroids, polyps, adenomyosis, hormonal changes near puberty or menopause, bleeding disorders such as von Willebrand disease, some medicines and, rarely, endometrial cancer. Heavy periods can also cause iron-deficiency anemia, so a blood test is often done.
Related calculators
This calculator is for education only and is not a diagnosis or a method of contraception you can rely on by itself. Talk to your doctor, nurse or midwife about your cycle, bleeding or family planning.