The 24-question quiz that reveals your REAL biological age - and your risk of disease

Scientists have developed an online calculator that can reveal how old your body really is.

Longevity experts in New York City made the AI-powered tool that estimates one's biological age using 24 questions. All you need is an active email.

Biological age differs from chronological age because it looks at how old your cells are rather than how many birthdays you've had.

The older cells are, the more wear and tear they develop, which puts people at higher risk of chronic diseases such as cancer.

Experts say a good result is a biological age that is slightly younger than the chronological age — or the number of years someone has been alive.

But a biological age that matches the chronological age is also considered to be a good sign.

In cases where the biological age is greater, however, experts warn this may indicate a higher risk of heart disease, diabetes and death at a younger age.

The test also asks users for their arm circumference — but, if this is not known, users are told they can input the US average of 13 inches.

There is also a question on blood pressure — with users suggested to use data from the American Heart Association to estimate theirs in cases where they do not know.

A healthy range is 120/80mmHg, while an unhealthy one is 120 to 129 and less than 80.

Usually, the only way to accurately tell how old someone's cells are is to do a costly blood analysis. 

But the new test is free, involves no needles and is based on results from 47,000 Americans and Europeans.

People taking the test first answer questions on their ethnicity, gender, education level and income.

They are then queried on lifestyle, including weight gain in recent years, their alcohol consumption and if they get out of breath walking up stairs.

The tool — developed by longevity company NOVOS — then analyzes the data to reveal a biological age, which is sent to users via email.

It is also possible to complete the quiz in the company's app, which will give recommendations on how to improve age — such as reducing coffee consumption or setting a consistent bedtime. You can access the test on the app here.

Chris Mirabile, who founded NOVOS, said they have made the tool to make an estimate of biological age more accessible for all.

'The longevity movement has gained traction among enthusiasts, but the real, daily practice of it is still too gatekept,' he said.

'We want to give people free tools that they can use to live healthier for longer. Everyone deserves to know their biological age and how certain lifestyle changes can slow it.'

The test is based on a biological clock developed by longevity experts Dr Su-In Lee and Dr Matt Kaeberlein, from the University of Washington.

Dr Kaeberlein was the first scientist to suggest that resveratrol — a substance found in red wine — could help to reduce someone's biological age, following studies on worms.

This research was later followed up by Dr David Sinclair, a longevity researcher at Harvard University, although clinical trials have not conclusively shown that the substance can slow aging.

Among those to successfully de-age themselves after finding out their biological age was 64-year-old grandmother-of-11 Amy Hardison from Mesa, Arizona.

The author and motivational speaker has done an hour of aerobic exercise every day for five decades, weight lifted, stretched and never taken supplements until recently — when she started taking NOVOS Core.

But despite this she ranked fourth on the Rejuvenation Olympics — a contest for health obsessives — beating the lines of billionnaire Bryan Johnson.

She is currently aging at a rate of 0.74 of a year per chronological year, according to her epigenetic test, well below the average.

Revealing her reaction to the results, she told The Times: 'I just kind of giggled. It was pretty ironic that I even did it because I've never been into taking vitamins and supplements.'