Open today until 18:1530+ NHS & private services · same-week appointments, walk-ins welcome 139 New Road, Chatham · 2 min from the station
Open until 18:15 · 30+ services · walk-ins welcome
FREE TOOL · NOTHING STORED

BMI calculator

Work out your BMI in under a minute, in centimetres and kilograms or in feet and stones. You will see your NHS weight category, the healthy weight range for your height, and whether you meet the threshold for treatment at our Chatham clinic.

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A RESULT IN UNDER A MINUTE

Calculate your BMI

Awaiting your measurementsEnter your height and weight and we will work out your BMI and whether our clinic can treat you.

This calculation happens in your browser and stops there. Nothing is sent to us, nothing is saved, and the figures disappear when you close the tab. You do not need to give us a name or an email address to use it.

What the NHS weight categories mean

BMI divides your weight in kilograms by the square of your height in metres. The resulting figure is placed into one of six bands. These are the bands the NHS uses, and the ones our pharmacist will refer to at your consultation.

  • Underweight0 to 18.5
  • Healthy weight18.5 to 25
  • Overweight25 to 30
  • Obese class I30 to 35
  • Obese class II35 to 40
  • Obese class III40 and above

The BMI you need for weight loss treatment

The NHS weight categories above describe your weight. They are not the same thing as whether a clinic can treat you, which is a separate and stricter question.

At our Chatham clinic, a BMI of 30 or above meets the main criterion on its own. Between 27 and 30 you also qualify if you have a weight-related condition, which in practice usually means type 2 diabetes, high blood pressure, obstructive sleep apnoea, raised cholesterol or a diagnosis of pre-diabetes. Below 27 we will not prescribe weight loss medication.

That last line matters more than the first two. If a provider offers to prescribe a GLP-1 medicine to someone with a BMI in the healthy range, they are not following the guidance, and the fact that a website will take the payment does not make it safe. We would rather lose the booking than take it.

Lower thresholds for some ethnic groups

Weight-related health risks appear at a lower BMI in people of South Asian, Chinese, Black African and African-Caribbean family background, and NHS guidance asks clinicians to use lower cut-offs accordingly. This calculator shows the standard bands. Raise it at your consultation if it applies to you and the pharmacist will apply the right threshold.

What BMI cannot tell you

BMI knows two things about you: your height and your weight. It does not know how much of that weight is muscle, where you carry it, what your blood pressure is doing, or what your blood results say. A rugby player and someone carrying the same weight as visceral fat get the same score, and they are not in the same position.

Waist measurement is often the more useful number, because weight carried around the middle is the pattern most strongly associated with cardiovascular risk and type 2 diabetes. We measure both at the clinic, alongside a blood pressure check, and treat BMI as the opening question rather than the answer.

It is also the wrong tool for some people entirely. It is not validated for under-18s, who are measured against age and sex centiles instead, and it is not meaningful during pregnancy or while breastfeeding. If any of that applies, speak to your GP rather than acting on the figure above.

What happens next

If your result suggests you may be eligible, the next step is a free consultation at 139 New Road in Chatham. The pharmacist measures your height and weight properly rather than relying on what you typed, takes a full medical history, checks your current medicines for interactions, and talks through whether treatment is appropriate. You can read what a full pathway looks like on our treatment information page, or compare the two main options on our Mounjaro and Wegovy comparison.

Nothing is prescribed on the strength of a number typed into a website, here or anywhere else that is doing it properly.

BMI calculator questions

No. BMI is a screening figure, not a diagnosis. It compares your weight to your height and nothing else, so it cannot see muscle, bone density, where you carry weight, or your blood results. A very muscular person can read as overweight while being nothing of the sort. We use it as the opening question at the clinic, never the closing one.

Clinical review

Reviewed by the responsible pharmacist at Chatham Pharmacy

GPhC registered. This page is general information about a service we provide, not personal medical advice, and it is no substitute for a consultation. Anything prescribed at our clinic follows an assessment in person at 139 New Road.

WEIGHT LOSS · MEDWAY TOWNS

A weight loss clinic for the whole of Medway

We are on New Road in Chatham, a few minutes from the station and with free parking outside. Patients travel to the clinic from across the Medway towns and from Maidstone.

ChathamME4 · you are here
RochesterME1 · 6 min
GillinghamME7/ME8 · 8 min
WaldersladeME5 · 9 min
StroodME2 · 10 min
RainhamME8 · 12 min
MaidstoneME14 · 20 min
VISIT THE PHARMACY

Find us in Chatham

We are based on New Road in Chatham, a short walk from the station and with parking nearby. Walk-ins are welcome when slots are free.

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139 New Road, ChathamME4 4PT
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Mon–Fri 9:00–18:15Closed for lunch 13:00–14:15
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01634 404142Call or WhatsApp before visiting
Get directions

Know your number. Now talk it through.

A BMI figure is a starting point, not a plan. Book a free consultation and our pharmacist will check your measurements properly, go through your history and tell you honestly whether treatment is right for you.