SectionHealth & Wellbeing
Tools26 calculators
Last reviewed28 July 2026
Calculator dataHealth details are never transmitted or stored

26 health tools, grouped by what they measure

These are population-level estimates, not assessments of you. They are useful for spotting a rough direction of travel and for making sense of guidance you have already been given. They cannot diagnose anything, and none of them replaces a conversation with a GP, pharmacist or registered dietitian.

Every calculator in this section now carries a full explanation: what it works out, the method, a worked example, the mistakes people make, and the size of its own error. Where a target comes from UK guidance the source is named, and where the arithmetic rests on a population average the page says so rather than presenting the result as a measurement.

If you are not sure where to begin, these tools answer the questions readers ask most often in this section.

Daily Calorie CalculatorThe clearest starting point for understanding energy needs. Alcohol Unit Calculator UKConverts real drinks into UK units, which are rarely intuitive. Hydration PlannerA sensible fluid target with a practical schedule for the day. Sleep Recovery PlannerShows how a week of short nights actually accumulates. Waist-to-Height CalculatorA simpler and often more informative measure than BMI alone. Target Heart Rate CalculatorPuts a training zone around a number you can actually check.

Body measurement estimates 4 tools

Ratio-based measures that describe a population average rather than an individual's health.

BMI CalculatorCalculate body mass index. Waist-to-Height CalculatorCalculate waist-to-height ratio. Body Fat EstimatorEstimate body fat using BMI and age. Healthy Weight Range CalculatorEstimate weight at a selected BMI.

Energy and daily calories 3 tools

Estimated energy requirements from body size, age and activity level.

BMR CalculatorEstimate basal metabolic rate. Daily Calorie CalculatorEstimate daily energy needs. Walking Calories EstimatorEstimate calories burned from distance, pace and body weight.

Diet and nutrient targets 6 tools

Comparisons against published UK reference intakes for the nutrients people ask about most.

Protein Intake CalculatorEstimate daily protein target. Fibre Intake CalculatorCompare fibre intake with a target. Daily Fibre Intake CheckerEstimate fibre intake from common foods and compare with a daily target. Salt Intake CalculatorCompare salt intake with a target. Sugar Intake CalculatorCompare daily sugar with a target. Vitamin & Mineral Symptom CheckerSelect symptoms and see ranked possible vitamin and mineral deficiency links, with food sources, safety notes and suggested next steps.

Hydration, caffeine and alcohol 5 tools

Fluid targets and the drinks that carry their own guidance thresholds.

Hydration CalculatorEstimate daily fluid target. Hydration PlannerEstimate a sensible daily fluid target and get a simple drinking schedule for the day. Caffeine Intake CheckerAdd up caffeine from tea, coffee, energy drinks and cola. Alcohol Unit Calculator UKCalculate UK alcohol units from drink strength and volume. Blood Alcohol EstimatorRoughly estimate alcohol concentration.

Movement and exercise 3 tools

Pace, distance and training heart-rate ranges for walking, running and cycling.

Walking Pace CalculatorCalculate walking pace. Running Pace CalculatorCalculate running pace. Target Heart Rate CalculatorEstimate a training heart-rate target.

Sleep and daily habits 4 tools

Sleep timing and recovery, and the sedentary habits that build up without being noticed.

Sleep Cycle CalculatorEstimate sleep cycles in a chosen duration. Sleep Recovery PlannerCalculate weekly sleep debt and create a practical recovery plan. Sitting Time CalculatorEstimate weekly sitting time. Screen Time Health CheckerCalculate weekly recreational screen time. Pregnancy Due Date CalculatorEstimates a due date from a last period, conception date or IVF transfer.

Common questions

Can these tools tell me whether I am healthy?

No, and it is worth being blunt about that. Every calculation here is derived from population averages. BMI cannot distinguish muscle from fat and was never designed to assess an individual. Calorie estimates carry an error margin of several hundred calories a day. A symptom checker can list associations but cannot diagnose. Use these to frame a question for a health professional, not to answer one.

Where do the reference values come from?

UK public health guidance, principally the NHS and the Scientific Advisory Committee on Nutrition, together with the standard published equations for basal metabolic rate and heart-rate zones. The specific sources are set out on my references page, and every threshold is shown as an editable field so you can substitute a figure your clinician has given you.

Should I use these if I have a health condition?

Treat them with caution and defer to advice you have already been given. Pregnancy, diabetes, kidney or heart conditions, eating disorders, and many medications all change what is appropriate — sometimes substantially. Generic targets can be actively unhelpful in those situations. If you are under the care of a professional, their figures replace these.

How reliable is the blood alcohol estimate?

It is an illustration of how alcohol is processed, not a measurement. Widmark-type calculations assume an average distribution and elimination rate, and real values vary widely between people and between occasions depending on food, sex, medication, liver function and how quickly the drinks were taken. It cannot tell you whether you are fit to drive. If you have been drinking, do not drive.

Is anything I enter about my health stored?

No. Weight, height, symptoms, sleep patterns and drinking figures are processed entirely within your browser. Nothing is transmitted to a server and nothing is kept as a calculator record. Closing the tab discards it.

Where can I get proper advice?

In the UK, start with NHS 111 or the NHS website for general guidance, your GP practice for anything persistent or worrying, and a community pharmacist for medication questions — they are free to consult and often available the same day. For mental health, eating concerns or alcohol, your GP can refer you to specialist services.

Questions rarely sit inside a single subject. These sections cover the calculations most often needed alongside health estimates.

Everyday LifeScreen time, routine and other habit-shaped calculations. Travel & TransportWalking and cycling times, and rest breaks on long journeys. Finance & BudgetingFood budgeting and the cost of everyday habits. GardeningActivity that happens outdoors rather than in a gym. Forensic ScienceThe same elimination and half-life arithmetic in a different context. All toolsEvery calculator on the site in one browsable list.
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