Hematocrit Calculator
Estimate hematocrit levels from hemoglobin or RBC count and compare against WHO/NIH reference ranges by age and gender.
About
The Hematocrit (Hct) represents the volume percentage of red blood cells (RBCs) in blood. It is a critical metric for diagnosing conditions such as anemia (low Hct) or polycythemia (high Hct). While direct measurement via centrifugation is the gold standard, hematocrit is frequently estimated clinically using Hemoglobin (Hb) levels or RBC count when direct measurement is unavailable.
This tool utilizes the standard clinical rule of thumb where Hct ≈ Hb × 3, alongside more granular formulas involving Mean Corpuscular Volume (MCV). It includes a comprehensive reference database derived from WHO and NIH standards, allowing you to instantly benchmark results against age and gender-specific norms.
Formulas
The estimation of Hematocrit relies on the morphological relationship between red blood cells and hemoglobin content. The primary conversion formulas are:
1. Hemoglobin Method (Standard Rule):
Hct = Hb × 2.941
2. RBC Count Method:
Hct = RBC × MCV10
Where Hb is in g/dL, RBC is in 106/μL, and MCV (Mean Corpuscular Volume) is in fL.
Reference Data
| Demographic Group | Lower Limit (%) | Upper Limit (%) | Clinical Significance |
|---|---|---|---|
| Newborns | 45 | 61 | Physiological Polycythemia |
| Infants (1-6 mos) | 30 | 44 | Physiological Anemia |
| Children (1-10 yrs) | 35 | 45 | Growth Phase |
| Adult Males | 40 | 54 | Androgen Influence |
| Adult Females | 36 | 48 | Menstruation Impact |
| Pregnant (3rd Tri) | 28 | 40 | Hemodilution |
| Elderly (>65) | 36 | 52 | Bone Marrow Changes |