Biological and chronological age calculator

Chronological age is the exact time since birth, in years, months and days. Biological age from a blood test uses 9 routine results in the PhenoAge formula, published in 2018: for a 50-year-old's report with glucose 90 mg/dL, CRP 2 mg/L and RDW 13%, it gives 43.9 years, 6.1 below their age.

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Grab your latest complete blood count and blood chemistry: 9 results, plus your age.

Your age

Age (years)From 20 to 100 years: the formula was built on adults.

Complete blood count

White blood cellsWhite cell count. Enter 6500 (/mm³) or 6.5 (thousand/mm³).

Lymphocytes (%)White cell differential: the % value, not the absolute count.

MCV (fL)Red cell indices: mean corpuscular volume.

RDW (%)Red cell indices. It carries the most weight in the formula.

Blood chemistry

Fasting glucose (mg/dL)May appear as “Fasting blood sugar”.

Creatinine (mg/dL)A kidney function test.

Albumin (g/dL)Sometimes listed under “Total protein and fractions”.

CRP, C-reactive proteinIf the report says “< 0.5”, enter 0.5.

Alkaline phosphatase (U/L)A liver and bone enzyme.

Accepts a decimal point or comma (0.9 or 0,9); type thousands without a separator (6500). Values stay in your browser.

Enter your age and the 9 results from your report, or use the sample report to see the calculation.

Not a diagnosis. PhenoAge sums up 9 tests as one age and was designed to estimate risk in groups of people. Your results are for your doctor to interpret, who knows your history.

Which tests measure biological age: the 9 on the report

PhenoAge uses 4 results from the complete blood count and 5 from blood chemistry. All are routine tests; albumin, CRP and alkaline phosphatase are sometimes left out of a check-up and have to be requested.

Test	Where it appears on the report	Unit	Watch out
White blood cells	CBC, white cell section	/mm³ or thousand/mm³	6500/mm³ is the same as 6.5 thousand/mm³; the calculator understands both.
Lymphocytes (%)	CBC, white cell section	%	Use the percentage, not the absolute count in the next column.
MCV (fL)	CBC, red cell section	fL	Also listed as mean corpuscular volume.
RDW (%)	CBC, red cell section	%	The heaviest weight in the formula: 1 point of RDW is worth 3.7 years.
Fasting glucose (mg/dL)	Chemistry: glucose or fasting glucose	mg/dL	If in mmol/L, multiply by 18 before entering.
Creatinine (mg/dL)	Chemistry: creatinine	mg/dL	If in µmol/L, divide by 88.4.
Albumin (g/dL)	Chemistry: albumin or total protein and fractions	g/dL	If in g/L, divide by 10. Not every check-up includes it: check the test order.
CRP, C-reactive protein	Chemistry: C-reactive protein (high-sensitivity CRP)	mg/L or mg/dL	Select the unit on your report. A result of “< 0.5” goes in as 0.5.
Alkaline phosphatase (U/L)	Chemistry: alkaline phosphatase	U/L	Not every check-up includes it: check the test order.

No lab results at hand: your numbers and the guidelines

Nothing here becomes an age: each number is compared with the official cutoff in force in 2026. Fill in only what you know.

Fasting blood glucose (mg/dL)

Systolic blood pressure (mmHg)Diastolic blood pressure (mmHg)

Waist (cm)

Moderate activity (min/week)Vigorous activity (min/week)

Vigorous activity counts double. A single blood pressure or glucose reading does not make a diagnosis.