Free GLP-1 tools and calculators
Every calculator and comparison tool Monj builds, in one place. Work out your BMI, daily energy needs and calorie target, count pen clicks accurately, compare medicines on trial data, and check live UK pharmacy prices. All free, all running in your browser, with no account and no personal data stored.
Body and energy calculators
Start with measurement, then work out what your body actually needs. Each of these updates instantly as you type, in kg and cm, stone and pounds, or US pounds.
Instant adult BMI with NHS-aligned categories, plus waist risk thresholds, waist-to-hip ratio, Navy body fat and skinfold estimates for the context BMI alone cannot give.
Check your BMI → EnergyBMR & TDEE CalculatorYour basal metabolic rate and total daily energy expenditure from one form, using the Harris-Benedict equation with a transparent activity multiplier table.
Work out your TDEE → PlanningDaily Calorie Needs CalculatorTurn maintenance calories into a goal-based daily target with a protein, carbohydrate and fat split, and an honest answer on whether 1,200 calories is safe.
Set your target → ProgressWeightCompareSee how your weight loss compares against typical trial and real-world trajectories, so you can judge progress against something meaningful rather than guesswork.
Compare progress →Dose and pen tools
Practical tools for people already on treatment. Click counting matters because a miscount is a dosing error, so these exist to remove the arithmetic.
Convert between millilitres, milligrams and KwikPen clicks for any Mounjaro dose, with the exact and rounded figures shown side by side.
Open the calculator → SemaglutideWegovy Click CalculatorThe same click-to-dose conversion for Wegovy pens, for anyone tracking partial doses or verifying what a pen has left.
Open the calculator → ReferenceKwikPen Click ChartA printable reference chart mapping clicks to doses across every KwikPen strength, for when you want the numbers on paper rather than on screen.
View the chart → TrackingDoseDiaryLog injection dates, doses and sites so you can see your titration history at a glance and avoid reusing the same injection area.
Open DoseDiary →Price and medicine comparison
The tools that do the job Monj exists for: comparing what treatments cost and how they differ clinically, with no pharmacy able to pay for position.
Live price leaders for every GLP-1 medicine we track, dose by dose, across GPhC-registered UK pharmacies, with the last verified update time shown.
Compare prices → Clinical dataMed Compare ToolPut medicines side by side on trial weight loss, dosing schedule, administration route and licensed indications, weighted by the criteria that matter to you.
Compare medicines → Discounts appliedMounjaro Discount Price ListPharmacies ranked by lowest total first-order cost with working discounts already applied, so the ranking reflects what you actually pay.
See the price list → Buyer’s guideHow to Compare Mounjaro PricesWhat actually changes the total, first-order versus repeat pricing, and how to spot-check you are not overpaying before you order.
Read the guide → DirectoryPharmacy DirectoryEvery GPhC-regulated pharmacy and clinic we track, grouped by type, each with its own page covering current offers and verification status.
Browse pharmacies →How these tools work, and what they are not
Every calculator runs entirely in your browser. Nothing you type is sent to us, stored, or linked to you, and none of them require an account. They give educational estimates using published equations, which are named on each page alongside their sources. They cannot assess your suitability for treatment, and they are not a substitute for a prescriber who can see your full medical history. See our full methodology.
Related resources
Independent look at injection and food logging apps available in the UK, and what to check before trusting one with your health data.
Read the roundup → GuideWhich GLP-1 is best?Every licensed UK treatment compared on average weight loss, the one head-to-head trial, injection versus tablet, eligibility and cost.
Read the comparison →Questions about these tools
Are the Monj tools free?
Yes. Every calculator and comparison tool is free, needs no account, and has no paid tier. Monj is funded through disclosed commercial arrangements with some pharmacies, which never affect rankings or results.
Is my data stored when I use a calculator?
No. The calculators run in your browser, and the figures you enter are never sent to our servers, saved or linked to you. Closing the page discards everything.
Can a calculator tell me if I can get a prescription?
No. A BMI result is only one input into prescribing. A qualified prescriber assesses your medical history, current medicines, conditions and safety checks before deciding whether treatment is appropriate.
Which click calculator do I need?
Use the Mounjaro click calculator for tirzepatide KwikPens and the Wegovy click calculator for semaglutide pens. The click chart covers the same conversions in printable form. If you are unsure how much is left in a pen, ask your pharmacy rather than estimating.
Tools built and maintained by Medstack Ltd (Company No. 16439872) under our editorial and review policy. Equations and thresholds are sourced from published clinical references, cited on each tool page. Monj does not sell, prescribe or dispense medicines. These tools provide educational estimates and are not medical advice.