Quick health estimates from everyday numbers like height, weight and dates. Nothing you type is sent to a server, and none of it replaces a doctor.
The calculators here take a handful of values anyone already knows — height, weight, age, the date a cycle started — and turn them into a rough read on the body. Nothing is drawn, nothing is scanned, so the precision ceiling is low. What you get instead is a measurement you can repeat any day and watch over time.
That makes the right question not «what is today's number» but «which way has it moved since last month». One reading says far less than the same reading taken the same way, repeatedly.
Body mass index divides weight by height squared. Its simplicity is also its limit: it cannot separate muscle from fat, and it cannot see whether fat sits around the waist or is spread across the limbs. Two people at BMI 22 — an athlete and someone sedentary — are in visibly different physical states.
The lines between underweight, normal and overweight also differ between standards. The WHO international cut-offs and the Asia-Pacific cut-offs place the overweight threshold at different points, so the same number lands in different bands depending on which table you read. That is why the calculator here shows both.
Treat it as a number that only becomes meaningful next to others: waist circumference, body fat percentage, blood pressure.
Basal metabolic rate is the energy spent at rest; multiplied by an activity factor it becomes total daily energy expenditure. The catch is that BMR is itself a regression fitted to a population sample. Mifflin-St Jeor, Harris-Benedict and Katch-McArdle return different numbers not because one is broken but because they were fitted to different samples.
The activity factor is cruder still. A band like «exercises three times a week» is interpreted differently by different people, so the same person can move their own result by hundreds of kilocalories just by reclassifying themselves.
The practical approach: hold the calculated intake for two weeks, watch what the scale does, then adjust to that observation. The formula is a starting point; your own data is the answer.
A due date is usually set by adding 280 days to the first day of the last period. That rule assumes a 28-day cycle with ovulation on day 14. If your cycle is shorter, longer or irregular, the estimate shifts by exactly that much.
Ovulation estimates share the structure. The luteal phase varies little between people, but the follicular phase varies a lot — so the more accurately you enter your own cycle length, the better the estimate gets.
When an ultrasound measurement disagrees with the calculated date, the ultrasound wins. Use the calculator to get a rough timeline and plan around appointments, not to settle one.
An eye chart measures resolving power at a fixed distance with optotypes of a fixed physical size. Reproducing that on a screen requires knowing the display size, its pixel density and your viewing distance. Get any one of the three wrong and the whole result shifts.
Screen brightness, ambient light, glare and eye fatigue move it further. So this is not a test that produces a prescription — it is a screening step that helps you notice a large difference between eyes, or a change from last time.
They are not diagnostic. They do not detect disease, do not recommend treatment or medication, and do not replace laboratory values. If you are pregnant or breastfeeding, or managing a chronic condition or medication, do not apply the calorie or weight targets here directly.
If a result is far from your usual pattern, or you have actual symptoms, the next step is a clinician rather than another run of the calculator. What these tools do well ends at recording where you are and showing how it changes.
Health data sits at the sensitive end of everything you could type into a website. Every calculation in this category runs inside the browser and none of the values are transmitted anywhere. There is no account and no sign-in; if you want a record, copy the result yourself.