ICH Volume Calculator
Estimate intracerebral hemorrhage volume with either the ABC/2 shortcut or an ellipsoid approximation.
Enter three orthogonal hemorrhage diameters in centimeters, choose a method, and calculate an estimated bleed volume with a simple severity classification.
ICH Volume Calculator
Estimate intracerebral hemorrhage volume with either the ABC/2 shortcut or an ellipsoid approximation.
About ICH volume estimation
Estimating intracerebral hemorrhage volume is a routine part of stroke and neurocritical care because clot size strongly influences severity, mass effect, and prognosis. In many acute settings, clinicians need a quick calculation before advanced software or formal volumetric segmentation is available. The ABC/2 method became popular because it can be performed rapidly on CT by measuring the largest hemorrhage diameter, a perpendicular width, and an approximate depth. Multiplying those values and dividing by two gives a fast bedside estimate that is often close enough to support triage and communication.
The ellipsoid method uses a geometric formula that assumes the bleed resembles an ellipsoid. It is still an approximation, but it can be a useful comparison when the hemorrhage contour is smoother or when a team wants a slightly more formal geometric estimate. Neither method is perfect. Irregularly shaped bleeds, layered blood products, mixed-density lesions, or substantial intraventricular extension can all make simple three-diameter models less accurate. Even so, these quick formulas remain clinically helpful because they provide a shared language for describing size and for connecting that size to prognosis studies and scoring systems.
This calculator labels the result as mild, moderate, large, or massive using a simple volume-based scale. Those labels are descriptive rather than diagnostic. A small brainstem hemorrhage can be far more dangerous than a larger lobar hemorrhage, and location, hydrocephalus, blood pressure, anticoagulation, and neurologic examination all matter. Volume is one dimension of severity, not the whole story. Small differences in how A, B, or C are measured can also shift the result substantially, especially when diameters are rounded aggressively.
Use this tool as a rapid estimation aid and as a teaching tool for understanding how bedside formulas work. It is not a substitute for formal radiology review, specialist interpretation, or serial imaging. When treatment decisions are urgent, the trend in the patient’s examination and the anatomy of the bleed remain just as important as the numeric volume estimate.
ICH volume examples
These sample calculations compare the two formulas and show how the same diameters can produce slightly different estimates.
| Input | Output | Note |
|---|---|---|
| A 3 cm, B 2 cm, C 2 cm, ABC/2 | 6 mL → Mild | A small estimated bleed volume using the rapid bedside method. |
| A 4 cm, B 3 cm, C 4 cm, ABC/2 | 24 mL → Moderate | A middle-range estimate that still needs close clinical interpretation. |
| A 5 cm, B 4 cm, C 5 cm, Ellipsoid | 52.36 mL → Large | A larger volume estimate generated with the ellipsoid approximation. |
How to use it
- Measure the hemorrhage in three perpendicular dimensions on imaging and enter the values in centimeters.
- Choose ABC/2 for the common bedside shortcut or Ellipsoid for a geometric alternative.
- Click Calculate to estimate the volume in milliliters or cubic centimeters.
- Review the severity label and note while keeping location and exam findings in mind.
Frequently asked questions
Why is ABC/2 used so often?
It is fast, easy to remember, and usually accurate enough for acute bedside decision support when formal volumetric tools are unavailable. Validation studies have shown that ABC/2 correlates well with software-assisted volumetric measurements in most clinical hemorrhage shapes.
Is mL the same as cm³ here?
Yes. For this purpose, 1 milliliter is numerically equivalent to 1 cubic centimeter.
Which method is better?
Neither is universally better. ABC/2 is the standard quick method, while the ellipsoid formula can be a useful comparison for smoother shapes.
Can irregular hemorrhages be underestimated?
Yes. Highly irregular, multilobulated, or mixed-compartment bleeds can be poorly represented by simple diameter-based formulas.
Does a large volume always mean a worse outcome?
Not always, but larger volume is generally associated with greater severity. Location and clinical status can still outweigh size alone.