Tally pads, tampons, clots and flooding episodes across your period to calculate your Pictorial Blood loss Assessment Chart (PBAC) score — a validated screening tool used to describe how heavy a period is.
The PBAC score is a points-based tally used to describe how heavy a period is, based on how many pads and tampons you used, how soiled they were, how many clots you passed, and any flooding episodes. Points are added up across your whole period. A total score of 100 or more is the threshold most commonly used to flag bleeding associated with heavy menstrual bleeding (menorrhagia) — it is a screening indicator, not a diagnosis.
⚕️ Medical Notice: This is a validated screening tool, not a diagnosis. Heavy menstrual bleeding has many possible causes — including fibroids, hormonal imbalance, bleeding disorders, and more — that only a doctor can properly assess. If your score is at or above the threshold, or your bleeding is affecting your life, talk to your doctor.
| Category | Subtotal |
|---|
Each item you use during your period is scored according to how soiled or large it is, then every point is added together across the whole cycle to give one total score.
| PBAC Score | General Interpretation |
|---|---|
| Under 100 | Within the range not typically associated with heavy menstrual bleeding |
| 100 or above | The most commonly used threshold correlating with heavy menstrual bleeding (menorrhagia) |
A few practical things can influence how accurate your tally is, which is worth keeping in mind when you review your result:
The Pictorial Blood loss Assessment Chart, generally known as the PBAC score, is the Higham PBAC scoring system — a validated clinical tool designed to turn a subjective experience ("my period feels heavy") into a consistent, countable score. Before tools like this existed, doctors largely relied on a patient's own description of their bleeding, which can vary enormously from person to person and doesn't always line up with objectively measured blood loss. The PBAC approach instead asks you to keep a simple running tally of everything used across your period — pads, tampons, clots, and any flooding episodes — and to note how soiled or large each one was.
Each entry is weighted with points reflecting roughly how much blood loss it represents: lightly stained items carry the fewest points, moderately stained items more, and fully saturated pads or tampons the most. Clots and flooding episodes are scored separately, since they represent a different pattern of loss to what's absorbed by a pad or tampon. Adding every point together across the whole period gives a single total score, which can then be compared against a threshold — commonly 100 — that has been found to correlate with clinically measured heavy menstrual bleeding.
A high PBAC score simply describes the amount of bleeding — it doesn't explain why it's happening. Heavy menstrual bleeding can have several different underlying causes, and working out which one applies to you requires an assessment by a doctor.
What is the PBAC score?
The PBAC (Pictorial Blood loss Assessment Chart) score is a scoring system developed to give a more consistent, numerical way of describing how heavy a period is, rather than relying on vague descriptions like "heavy" or "light". It works by assigning points to pads, tampons, clots and flooding episodes based on how soiled or large they are, then adding these points up across an entire period.
How is the PBAC score calculated?
Points are assigned per item used across your whole period: 1 point for a lightly stained pad, 5 points for a moderately stained pad, and 20 points for a fully saturated pad. Tampons score 1 point lightly stained, 5 points moderately stained, and 10 points fully saturated. Clots score 1 point if small (roughly the size of a 5-cent coin) and 5 points if large (roughly the size of a 50-cent coin). Each episode of flooding or an accident adds 5 points, and all points are added together for a total score.
What does a score of 100 or more mean?
A total PBAC score of 100 or more is the threshold most commonly used in clinical settings to flag bleeding that correlates with objectively measured heavy menstrual bleeding, also called menorrhagia. It is a validated screening indicator rather than a diagnosis, and reaching this score is generally considered a reasonable prompt to discuss your bleeding pattern with a doctor. Some guidelines use a slightly higher threshold of around 150, so it's treated as a guide rather than an exact cut-off.
Is heavy bleeding always a problem that needs treatment?
Not automatically. Bleeding patterns vary a lot between individuals, and a higher score doesn't necessarily mean something is wrong. That said, it is worth having assessed by a doctor, particularly if it is new, has been getting worse, or is affecting your daily activities, sleep, work or energy levels.
What causes heavy menstrual bleeding?
There are many possible causes, and a doctor is needed to work out which, if any, applies to you. Common contributors include uterine fibroids, hormonal imbalances affecting ovulation, underlying bleeding disorders, and certain types of intrauterine devices (IUDs). Other causes can include polyps, adenomyosis, thyroid conditions, and some medications.
Should I track this every cycle, or just once?
Tracking your tally over one or two full cycles generally gives a more reliable picture than trying to estimate from memory or a single unusual period. Bleeding can vary cycle to cycle, so a couple of tracked cycles helps you and your doctor see a more representative pattern.
Is the PBAC score the only way doctors assess heavy bleeding?
No. A PBAC-style tally is one useful screening tool, but doctors typically also ask about symptoms of anaemia, such as fatigue, dizziness or paleness, may order blood tests to check iron levels and blood counts, and can use pelvic ultrasound or other imaging to look for structural causes such as fibroids or polyps.
Can heavy bleeding cause anaemia?
Yes. Losing a significant amount of blood each cycle can gradually deplete your iron stores and lead to iron-deficiency anaemia, with symptoms like fatigue, breathlessness, dizziness or pale skin. If your PBAC score is elevated, it may be worth discussing iron levels with your doctor — our Iron and Calcium Needs Calculator can also help you think about dietary intake.
How accurate is a self-tallied PBAC score?
It relies on your own observation and recall, so it is an estimate rather than a laboratory measurement of blood loss. Even so, research comparing PBAC scores with directly measured blood loss has found it to be a reasonably reliable screening approach, which is why it continues to be used as a practical, low-cost tool in clinical settings.
What should I do if my score is at or above 100?
Treat it as a prompt to book an appointment with your GP, rather than a diagnosis on its own. Bring your tally with you, along with notes on how long your bleeding lasts and any other symptoms like clotting, pain or fatigue, so your doctor has a clear picture to work from.