Biological Age Calculator

How This Biological Age Calculator Works

This calculator applies the PhenoAge algorithm to nine blood biomarkers and chronological age to estimate mortality risk in years. In 2018, Levine and colleagues built Phenotypic Age from third National Health and Nutrition Examination Survey (NHANES III) data on 9,926 adults with more than 23 years of mortality follow-up. A penalized Cox regression narrowed 42 biomarkers to nine measurements. Gompertz regression estimates 10-year mortality risk.

Liu and colleagues define Phenotypic Age as the population age reflecting that mortality risk. In Levine and colleagues' NHANES IV validation sample of 6,209 adults, phenotypic age correlated with chronological age at r = 0.94. After adjusting for chronological age, each extra year of phenotypic age was associated with a 9% higher risk of death from any cause (hazard ratio [HR] 1.09). In 11,432 adults studied by Liu and colleagues, the hazard ratio remained 1.09 (95% confidence interval 1.08 to 1.10). Individuals with more illnesses showed older phenotypic ages.

The calculator converts US report units to the formula's units before it runs. Calculations use constants printed in Levine and colleagues' Supplement 1. A 2019 correction to Liu and colleagues prints slightly different final constants, and on this site's test cases the two versions give results about 1 to 2 years apart. Under the result, the calculator lists how many years the estimate would drop if each marker were 10% more favourable to the formula. More favourable means higher for albumin and lymphocyte percent and lower for the other seven. That adjustment reflects formula arithmetic and provides no clinical advice. The calculator shows the gap between your estimate and your calendar age. It does not show a mortality probability or PhenoAgeAccel, which Liu and colleagues compute as a residual across a whole population.

Where to Get the Nine Numbers

Three laboratory orders supply all nine blood measurements used in this biological age calculation. According to MedlinePlus, a comprehensive metabolic panel (CMP) is a routine blood test that measures 14 different substances and is commonly part of a routine checkup. That panel provides albumin, creatinine, glucose, and alkaline phosphatase (ALP). Albumin prevents fluid leakage from blood vessels. Creatinine comes from muscle breakdown. Creatinine testing alone is not the best kidney measure because muscle mass influences overall waste production. Glucose supplies energy, while alkaline phosphatase concentrates in liver and bone tissue.

A standard complete blood count (CBC) measures red blood cells, white blood cells, platelets, hemoglobin, and hematocrit levels. Red blood cell indices report mean cell volume (MCV), typically 79 to 95 femtoliters. The red cell distribution width (RDW) measures volume variation among red blood cells. Lymphocyte percent needs a CBC with differential. According to MedlinePlus, a blood differential quantifies neutrophils, lymphocytes, monocytes, eosinophils, and basophils. White blood cells defend against infection and increase during sickness.

The ninth marker is C-reactive protein (CRP), produced by the liver during inflammation. MedlinePlus says a value of 0.8 to 1.0 mg/dL or lower "is thought to be a healthy amount." None of the sources on this page states whether the PhenoAge formula needs a standard CRP or a high-sensitivity (hs-CRP) test, and the calculator accepts a result from either. The biological age blood test page details test ordering. Additional guides cover the comprehensive metabolic panel, the CBC blood test, and CRP levels.

What Your Result Does and Doesn't Mean

A PhenoAge calculation reflects statistical mortality risk in population data and does not provide a medical diagnosis. Phenotypic age estimates the calendar age corresponding to that mortality risk in reference cohorts. Liu and colleagues noted their study lacked longitudinal data on disease incidence.

According to MedlinePlus, diet, activity level, medicines and not drinking enough water can affect blood test results, and infections can raise CRP and white blood cell count. MedlinePlus also says an abnormal level "doesn't always mean you have a medical condition that needs treatment." Levine and colleagues wrote that CRP, albumin, creatinine and glucose are still "fairly homogenous" in children, young adults and extremely healthy people. For those groups, DNA methylation algorithms may track pre-clinical aging differences more clearly.

In the CALERIE trial, calorie restriction slowed the pace of aging measured by the DunedinPACE DNA methylation algorithm by 2% to 3%. The authors report it "did not lead to significant changes" in DNA methylation clocks, including the methylation version of PhenoAge (DNAm PhenoAge) and GrimAge. Effect sizes reached d = -0.29 at 12 months and d = -0.25 at 24 months. Trajectories between control and restriction groups showed nearly 90% overlap.

The guide on biological age explains what biological age means and compares five published ways to measure it. The epigenetic clock overview explains how methylation algorithms evaluate cellular aging. Commercial testing kits are compared in the biological age test guide. Trial evidence is analyzed in the guide on how to lower biological age.