Habit evidence - range calculator
How obesity affects life expectancy: estimate a range, not a verdict
Updated 2026-06-14 - estimate language only
Obesity and a higher body-mass index are population-level risk factors that are associated with several chronic conditions, but a single BMI number should not be turned into a personal death date. Weight, body composition, fitness, and overall health all interact, so the honest way to show this is an estimate range with clear uncertainty.
Use the widget below for a life-table range, then use the full calculator if you want BMI and other habits included alongside activity, sleep, alcohol, and smoking. The framing here stays positive: obesity is described by WHO as largely preventable and manageable.
Interactive estimate
Mini habit-context calculator
The displayed band uses DaysLeft life-table logic; cited statistics below use public SSA, WHO, or CDC sources. This is an estimate band, not a medical diagnosis or a personal death prediction.
80% band
17-50 years
Broad remaining-time estimate range.
50% inner band
26-44 years
Narrower middle band, still not a date.
Smoker=yes uses the existing quick-intake defaults from DaysLeft until the full calculator asks amount and duration. HR index: 1.20.
Page statistics
Adults overweight worldwide (2022)
2.5B
WHO: in 2022, 2.5 billion adults aged 18 and older were overweight, which is 43% of adults.
Adults with obesity (2022)
890M
WHO: 890 million adults were living with obesity in 2022, about 16% of adults worldwide.
High-BMI deaths from NCDs
3.7M
WHO: higher-than-optimal BMI caused an estimated 3.7 million deaths from noncommunicable diseases.
US obesity-related medical cost
$173B
CDC: obesity accounted for nearly $173 billion in U.S. medical expenditures in 2019 dollars.
BMI is context, not a countdown
WHO defines overweight as a BMI of 25 or higher and obesity as 30 or higher in adults, and reports that the worldwide prevalence of obesity more than doubled between 1990 and 2022. These are population statistics that describe associated risk, not a forecast for any one person.
BMI alone cannot see muscle mass, fat distribution, fitness, or medical history, so this page keeps the result in a confidence band. The full DaysLeft calculator combines BMI with other factors and still labels the output as an estimate, not a diagnosis.
What to do with the result
WHO describes obesity and its related diseases as largely preventable and manageable, so the useful next step is not panic over a number. It is seeing how the estimate range responds when weight, activity, and other habits change in the full calculator.
Sustainable changes such as more regular activity, better sleep, and clinician-guided nutrition tend to matter more than chasing one figure. If weight is tied to a medical condition or distress, a clinician is the right resource rather than a calculator.
Sources
FAQ
Does obesity shorten life expectancy?
Obesity is associated at the population level with higher risk of several conditions, and WHO links higher-than-optimal BMI to millions of noncommunicable-disease deaths. This page uses estimate language and does not forecast an individual death age.
Why not show one number for a given BMI?
BMI does not capture body composition, fitness, or medical history, so a single number would overstate precision. DaysLeft shows a range and routes to the full calculator for more context.
What sources are used here?
The global statistics come from the WHO obesity and overweight fact sheet, the U.S. cost figure is from CDC, and the baseline life table is from the SSA.
Next step
The public table is only the starting point. Use the full calculator when you want habits and biological-age context included in the estimate band.