A menstrual blood loss chart turns the pads, tampons and clots you log into a number that shows whether your period is heavy. Below is how the main charts — the PBAC (Pictorial Blood Loss Assessment Chart) and the Menstrual Assessment Chart — are scored, how they define a "large" clot, and how PeriodVol does the same thing automatically in millilitres.
Open PeriodVol — the digital versionIt's a simple way to estimate how much you bleed without a laboratory test. Each day of your period you record how many pads or tampons you changed and how soaked they were, plus any clots or flooding. Each item is worth points (or, in PeriodVol, an estimated volume), and the total tells you whether your bleeding is in the normal range or heavy. These charts are widely used by doctors because objective blood-loss measurement (the laboratory "alkaline-haematin" method) isn't practical in everyday care.
The PBAC was introduced by Higham, O'Brien & Shaw in 1990 and is the most widely used pictorial chart. You match each product to a picture showing how stained it is, and add up the points for the whole period.
| Item | Lightly stained | Moderately soaked | Fully saturated |
|---|---|---|---|
| Pad | 1 pt | 5 pts | 20 pts |
| Tampon | 1 pt | 5 pts | 10 pts |
Plus: small clot = 1 point, large clot = 5 points, and each episode of flooding = 5 points. A total of 100 or more indicates probable heavy menstrual bleeding (menorrhagia), which corresponds to roughly more than 80 ml of blood loss per cycle. You can work out your own total with our free PBAC calculator.
Several health organisations publish their own version of the pictorial chart, all based on Higham's PBAC but with small differences — especially in how a clot's size is defined:
Since the original PBAC, several validated pictorial charts have been published. They fall into two types — those that give an abstract point score, and those calibrated to actual millilitres of blood (validated against the laboratory alkaline-haematin method):
| Chart | Output | Notes |
|---|---|---|
| PBAC — Higham 1990 | Points | The original; a score ≥ 100 suggests heavy bleeding. |
| Janssen chart — 1995 | Points | Refined visual chart; cut-off 185. |
| Barr chart — 1999 | Points | Pictorial chart developed for adolescents. |
| Wyatt pictogram — 2001 | Millilitres | Each icon = an actual mL value, validated vs alkaline haematin. |
| Magnay pictogram — 2014 | Millilitres | mL calibrated for modern superabsorbent ("ultra") towels. |
PeriodVol reports millilitres, like the Wyatt and Magnay pictograms, and also shows a PBAC-equivalent point score in its doctor report — so the result is comparable to whichever chart a clinician is used to.
There is no single universal cut-off, so charts vary. This is the comparison most people are looking for:
| Source | A "large" clot is… | Approx. size |
|---|---|---|
| Menstrual Assessment Chart (Canadian Hemophilia Society) | larger than 1 cm | ~1 cm |
| General HMB guidance (NHS / ACOG) | bigger than a 2.5 cm / 1 inch coin | ~2.5 cm |
| PeriodVol app | about a coin (~2.5 cm) — e.g. an Australian $1 coin | ~2.5 cm |
| Australian PBAC | about a 50-cent coin | ~3.2 cm |
Coins as a size guide: Australian 5-cent ≈ 19 mm · Australian $1 ≈ 25 mm · US quarter ≈ 24 mm · Korean 100-won ≈ 24 mm · Korean 500-won ≈ 27 mm · Australian 50-cent ≈ 32 mm. If you regularly pass clots bigger than a coin, that's worth mentioning to a doctor regardless of which chart you use.
A PBAC score is a clever proxy: a total of about 100 points lines up with the clinical 80 ml heavy-bleeding threshold first established by Hallberg's 1966 population study and used in the FIGO definition of abnormal uterine bleeding. But a score is abstract — "112 points" doesn't mean much on its own.
PeriodVol uses the same pictorial principle, but converts each product straight into an estimated volume in millilitres. You tap the pad, tampon or cup and how soaked it was; PeriodVol shows your blood loss per day and per cycle in ml, marks the 80 ml line, and can generate a doctor report that compares your cycles to the normal FIGO ranges. It's a digital, automatic version of the chart — no points to add up, and nothing leaves your phone.
Track it automatically with PeriodVolThe Pictorial Blood Loss Assessment Chart — a paper chart (Higham 1990) where you tally soaked pads/tampons, clots and flooding to estimate whether a period is heavy.
A score of 100 or more indicates probable menorrhagia (≈ more than 80 ml per cycle).
Pads: 1 / 5 / 20 points (light / moderate / saturated). Tampons: 1 / 5 / 10. Small clot 1, large clot 5, each flooding episode 5. Add across the whole period.
It depends on the chart: from larger than 1 cm (Canadian Hemophilia Society) to a 50-cent coin (Australian PBAC). A common rule is "bigger than a 2.5 cm coin." See the comparison table above.
The original validation reported sensitivity and specificity above 80% at a cut-off of 100, but accuracy varies between studies. It's a screening aid, not a diagnosis.
Yes — PeriodVol works like a digital pictorial chart and gives you an estimated volume in millilitres, privately, with no account.
PeriodVol is not a medical device and this page is educational, not medical advice. The scoring and thresholds above are drawn from the clinical literature below.