DaysLeft
a bio-age clock that shows a range, not a death date
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What is DaysLeft?
DaysLeft is a biological age and speed of aging calculator that provides a statistical estimate of your biological age rather than a medical diagnosis or prediction. The tool estimates your biological age based on lifestyle habits including smoking, exercise, diet, and sleep, showing how fast you're aging due to these choices. Unlike traditional life expectancy calculators that predict a specific death date, DaysLeft shows a range to emphasize uncertainty and avoid sensationalism. The calculator requires no signup and ensures user privacy by never sending inputs to a server. It is designed for individuals interested in longevity, biohacking, health optimization, and understanding how daily habits impact their aging process.
Key features include a free 2-minute biological age test, habit-based aging estimation, privacy-focused design with no server storage of inputs, and no signup requirement. The tool distinguishes between chronological age (calendar age) and biological age (how old your body seems to be), helping users understand their body's actual state relative to peers. Results are presented as educational estimates only, not medical advice.
DaysLeft is ideal for biohackers, longevity enthusiasts, health-conscious individuals, people looking to optimize their lifestyle for slower aging, and anyone curious about how habits like smoking, exercise quality, diet choices, and sleep patterns affect their biological aging speed.
DaysLeft pricing
Pricing model: Freemium
Free - The biological age test is completely free with no paid plans mentioned. No signup required and no premium tiers indicated on the website.
DaysLeft pros
- Free 2-minute biological age test
- No signup required to use
- Privacy-focused: inputs never sent to server
- Shows aging range instead of death date to reduce sensationalism
- Based on key lifestyle habits: smoking, exercise, diet, sleep
- Estimates speed of aging from habits
- Distinguishes biological age from chronological age
- Quick calculation process
- Statistical estimate clearly labeled as not medical diagnosis
- Educational and informational purpose only
- Helps identify impact of daily habits on aging
- Accessible web-based tool
- No server storage of personal inputs
- Focuses on actionable lifestyle factors
- Appears on Hacker News Show HN section
DaysLeft cons
- Not a medical diagnosis or prediction
- Only provides statistical estimates
- Limited to 4 habit categories (smoking, exercise, diet, sleep)
- No blood marker or biomarker input option
- Does not account for genetics
- No personalized intervention recommendations
- No follow-up tracking or progress monitoring
- Limited scientific validation mentioned
Frequently asked questions about DaysLeft
What is biological age?
Biological age is a statistical estimate of how old your body seems to be, reflecting the actual state of your body rather than just the number of years you've been alive (chronological age). It considers how well your cells, organs, and systems are functioning relative to your peers.
How is biological age different from chronological age?
Chronological age is the fixed number of years since your birth (your calendar age). Biological age is moving and can be slower or faster based on lifestyle choices, genetics, environment, and health conditions. Two people of the same chronological age can have different biological ages.
What habits does DaysLeft use to estimate biological age?
DaysLeft estimates biological age based on four key lifestyle habits: smoking, exercise, diet, and sleep. These factors are known to significantly impact how fast or slow you age.
Is DaysLeft a medical diagnosis?
No. DaysLeft provides a statistical estimate only and is explicitly not a medical diagnosis or prediction. It is for informational and educational purposes only, not medical advice, diagnosis, or treatment.
Do I need to signup to use DaysLeft?
No signup is required. You can use the biological age test immediately without creating an account or providing personal information.
Are my inputs sent to a server?
No, your inputs are never sent to a server. DaysLeft is designed with privacy in mind, keeping all your data local during the calculation.
Why does DaysLeft show a range instead of a death date?
DaysLeft shows a range rather than a specific death date to emphasize the uncertainty in aging predictions and avoid sensationalism. This approach is more honest about the limitations of biological age estimation.
How fast does the biological age test take?
The biological age test takes approximately 2 minutes to complete.
Is DaysLeft free to use?
Yes, the DaysLeft biological age test is completely free with no paid tiers mentioned on the website.
Can I reverse or slow my biological age?
Biological age is a moving target that can potentially be slowed or reversed through interventions in lifestyle factors like VO2 max, insulin sensitivity, mitochondrial health, diet, sleep, movement, stress management, and connection. DaysLeft helps you understand how your current habits impact your aging speed.