Small details matter in biological age calculation. That's why MyBioAge now uses your exact birth date—not just your birth year—for more precise calculations. This seemingly simple change makes your MyBioAge Index and Pace of Aging significantly more meaningful.

Why precision matters

Your biological age is compared to your chronological age. If the chronological age calculation is imprecise, everything built on top of it becomes less accurate. Using just birth year could mean being off by up to 364 days—nearly a full year of imprecision.

With your exact birth date, MyBioAge calculates your chronological age down to the day. This matters especially for:

Pace of Aging — Tracking whether you're aging faster or slower than time requires precise time measurement.
Progress tracking — Small improvements in biological age become visible when baseline calculations are precise.
Age-based comparisons — Reference ranges adjust based on your exact age, not just your decade.

Better Pace of Aging

Pace of Aging tells you whether you're biologically aging faster or slower than calendar time. This calculation depends on comparing your biological age change to chronological time passing. With imprecise chronological age, Pace of Aging becomes noisy and less reliable.

Using your exact birth date, MyBioAge can calculate Pace of Aging with greater confidence:

<1.0× — You're aging slower than time. Biological age is decreasing relative to chronological age.
1.0× — You're aging at exactly the rate of time.
>1.0× — You're aging faster than time. Time to focus on longevity habits.

Refined daily scoring

This update also includes refined day-to-day Recovery and Training Load scoring. The algorithms now account for more subtle variations in your daily patterns, reducing noise and making day-to-day changes more meaningful.

How to ensure accuracy

MyBioAge pulls your birth date from Apple Health. To ensure accuracy:

Open the Health app on your iPhone.
Tap your profile picture in the top right.
Verify your Date of Birth is correct.
If needed, tap Edit to update it.

Once your birth date is accurate in Apple Health, MyBioAge automatically uses it for all calculations.

Privacy note

Your birth date stays on your device like all other health data. MyBioAge reads it from Apple Health with your permission and uses it only for local calculations. There are no cloud uploads or external processing.