RBC Indices Calculator (MCV, MCH and MCHC from a blood count)

Understanding the RBC indices calculator — concept and principle

Red blood cell indices describe the average red cell: its size (MCV), how much haemoglobin it carries (MCH) and how concentrated that haemoglobin is (MCHC). This calculator works them out from the red cell count, haemoglobin and haematocrit, and flags whether each is in the usual adult range. They are the first step in working out the cause of anaemia.

Three ratios from one count: with the default inputs the result is MCV 89.4 fL (normocytic).

How it is calculated

MCV (fL) = haematocrit (%) × 10 ÷ RBC (×10¹²/L)

MCH (pg) = haemoglobin (g/dL) × 10 ÷ RBC

MCHC (g/dL) = haemoglobin (g/dL) × 100 ÷ haematocrit (%)

Typical adult ranges: MCV 80–100 fL, MCH 27–31 pg, MCHC 32–36 g/dL (each laboratory sets its own).

The principle

Haematocrit is the share of blood volume taken up by red cells. Dividing that volume by the number of cells gives the average cell volume. Dividing haemoglobin by the number of cells gives haemoglobin per cell, and dividing haemoglobin by red cell volume gives its concentration inside the cells. The factors 10 and 100 are unit conversions to femtolitres, picograms and g/dL.

Worked example

Default inputs: RBC 4.7 ×10¹²/L, haemoglobin 14 g/dL, haematocrit 42%.

MCV = 42 × 10 ÷ 4.7 = 89.4 fL → Normal size (normocytic).
MCH = 14 × 10 ÷ 4.7 = 29.8 pg → Normal (27–31 pg).
MCHC = 14 × 100 ÷ 42 = 33.3 g/dL → Normal (normochromic).

Each point is the calculator re-run with only “Red blood cell count (×10⁶/µL = ×10¹²/L)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Red blood cell count (×10⁶/µL = ×10¹²/L)	MCV (fL)
1.18	357.4
2.35	178.7
3.52	119.1
4.7	89.4
5.88	71.5
7.05	59.6
9.4	44.7

How to read the result

Where does your result fall?

Small cells (low MCV) suggest iron deficiency or thalassaemia; large cells (high MCV) suggest vitamin B12 or folate deficiency, alcohol, liver disease, an underactive thyroid or some medicines. Low MCH and MCHC point to pale (hypochromic) cells. Normal indices with anaemia suggest blood loss, kidney disease or chronic illness.

Common mistakes

Comparing with a different laboratory's reference range.
Expecting the calculated values to match the report exactly; analysers measure MCV directly and calculate haematocrit.
Interpreting indices without the full blood count and blood film.

Keep in mind: This is not a diagnosis. Abnormal blood counts should be interpreted by a doctor.

Frequently asked questions

What does a high MCV mean?

Red cells are larger than usual, most often because of B12 or folate deficiency, alcohol or certain medicines.

What is the difference between MCH and MCHC?

MCH is the amount of haemoglobin in each cell; MCHC is its concentration.

Can indices be normal in iron deficiency?

Yes, early on, before the cells become small and pale.

Sources: Wintrobe's Clinical Hematology (red cell indices and reference ranges)

Checked 9 Nov 2026. Formulas MCV = Hct/RBC, MCH = Hb/RBC, MCHC = Hb/Hct and reference ranges (MCV 80–100 fL, MCH 27–31 pg, MCHC 32–36 g/dL) as in “Red blood cell indices” (WikiProject Medicine / mdwiki, 2024 edition).

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