HCT / HGB Calculator — Hematocrit & Hemoglobin Conversion
Convert between hematocrit (HCT %) and hemoglobin (HGB g/dL) using the standard MCHC-based formula, and compare both values against published normal ranges for males and females.
Convert from
Sex
g/dL
g/dL
Status: Normal
- 1
HGB ÷ MCHC ratio
14.5 ÷ 33 = 0.4394Fraction of blood volume occupied by red-cell haemoglobin. - 2
Hematocrit (HCT)
0.4394 × 100 = 43.9
How does this calculator work?
HCT (%) = HGB (g/dL) ÷ MCHC × 100. With a typical MCHC of 33 g/dL, HCT ≈ HGB × 3 (the "rule of three"). Normal HGB is 13.5–17.5 g/dL for men and 12–15.5 g/dL for women; normal HCT is 41–53% and 36–46% respectively. Enter either value to convert and compare against sex-specific reference ranges.
Formula
How this is calculated
Hematocrit (HCT) is the percentage of blood volume occupied by red blood cells. Hemoglobin (HGB) is the concentration of the oxygen-carrying protein inside those cells, measured in grams per decilitre. The two quantities are closely related via mean corpuscular hemoglobin concentration (MCHC): HCT (%) = HGB / MCHC × 100. Rearranged: HGB = HCT × MCHC / 100.
The classic "rule of three" (HCT ≈ HGB × 3) assumes MCHC = 33 g/dL, a common population average for normal red blood cells. In practice MCHC ranges from about 30 to 36 g/dL, so the calculator exposes the MCHC field for a more accurate conversion. Patients with iron-deficiency anaemia often have low MCHC (hypochromic cells), which shifts the relationship — entering the measured MCHC from the full blood count panel improves accuracy.
Normal ranges shown are typical adult reference intervals. Males normally have higher HGB (13.5–17.5 g/dL) and HCT (41–53%) than females (HGB 12.0–15.5, HCT 36–46%), largely due to testosterone effects on erythropoiesis. Ranges also vary by altitude, laboratory method, and age.
Frequently asked questions
In a normal CBC result, HCT (%) ≈ HGB (g/dL) × 3. For example, HGB 14 g/dL gives HCT ≈ 42%. This assumes MCHC ≈ 33 g/dL. When MCHC is abnormal (e.g. iron-deficiency anaemia), the rule breaks down and you should use the actual MCHC value.
HCT below the normal range suggests anaemia — too few or too small red blood cells. Common causes include iron deficiency, vitamin B12 or folate deficiency, chronic disease, blood loss, or haemolysis. A complete blood count with iron studies and reticulocyte count helps identify the cause.
No. This is an educational conversion tool, not a diagnostic instrument. Interpreting haematology results requires clinical context, lab reference intervals that vary by instrument, and assessment of trends over time. Always consult a haematologist or physician.
Also known as
TG we-Calculate Editorial Team. (2026). HCT / HGB Calculator — Hematocrit & Hemoglobin Conversion [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hct-hgb-calculator
TG we-Calculate Editorial Team. "HCT / HGB Calculator — Hematocrit & Hemoglobin Conversion." TG we-Calculate. 2026. https://we-calculate.com/calculator/hct-hgb-calculator.
TG we-Calculate Editorial Team, "HCT / HGB Calculator — Hematocrit & Hemoglobin Conversion," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hct-hgb-calculator
@misc{wecalculate_hct_hgb_calculator, title = {HCT / HGB Calculator — Hematocrit & Hemoglobin Conversion}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hct-hgb-calculator}}, year = {2026}, note = {TG we-Calculate} }
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