Free tools

Open Community in the sidebar, then Free tools for a shelf of quick calculators and share-image makers. They are free on every plan, and they run on whatever numbers you type rather than on your log, which is what makes them useful for a what-if: what a dose change would look like, what you would be burning at a different weight, what a month costs before you order it.

They also live outside the app at tirzing.com/tools, where anyone can use them with no account and no sign-up, so you can send one to a friend who isn't a member, or post what you make without explaining what Tirzing is first.

Several of these overlap with parts of Tirzing that answer the same question from your own logged data, and do it better for exactly that reason. Each tool page ends with a link straight to its in-app counterpart, and the sections below say which one that is.

When will I hit my goal?

Two weigh-ins, where you started and where you are now, each with a date, and it works out your pace for you. It gives a goal date plus the nearer milestones (−5%, −10%, −15% of your starting weight), which are the ones worth planning around: they're close enough that a change of pace matters less.

It's a straight line through two points, and it says so. Weight loss slows down, so the further off your goal the more optimistic that date is. Inside Tirzing the same idea runs off your last eight weeks of weigh-ins with an earliest/latest band: see Predictions.

What is each pound costing you?

Medication, plus the visits and labs and syringes people forget, divided by what you've lost. It makes a share image, and the number is usually a surprise in one direction or the other. The in-app version (Insights → Cost & ROI) reads your actual vials and expenses instead of asking.

BMI calculator

Your BMI, the healthy range for your height, and the bit most BMI calculators skip: the exact weight that moves you into the next category down, and how far your BMI has already travelled if you add your starting weight.

TDEE & BMR calculator

Two numbers most calculators blur together. Your BMR is what you'd burn lying still all day: the lights-on cost of being you. Your TDEE is that multiplied by how active you actually are, which is what you'd have to eat to hold your weight. Give it your sex, age, height, weight and activity level and it works out both, then subtracts the deficit for the rate you want to lose and gives you a daily calorie target.

It also prices out every activity level side by side, so you can see what moving more would actually be worth, and it won't suggest a target below a safe floor (1,500 a day for men, 1,200 for women) no matter how aggressive a deficit you pick.

Medication level chart

Enter your dose, how often you take it, how long you've been on it and a half-life, and it charts an estimate of how the amount builds up and falls between doses. Picking a medication fills in an editable default half-life, the same one Tirzing starts that medication with in the app. It isn't medical information, so change it to anything you like, or choose Another medication and enter your own.

How long will my vial or pen last?

Enter what you have (vials, single-dose pens or KwikPens), your dose and how often you take it, and it works out how many doses your supply covers, the date of the last one and a reorder-by date. If your prescriber has set dose changes, tick the box and enter them: every dose is then counted at the amount it will be, and you see how much sooner that runs out than one dose throughout.

Single-dose pens are counted whole, one or more per dose. Your Supply page does the same from what's actually left in each vial and pen, and keeps itself up to date as you log shots.

Printable GLP-1 log

A blank shot and weigh-in log to print, and the same columns as a spreadsheet for Google Sheets or Excel. Handy for anyone who likes paper, or for a friend who is not ready for an app. A filled-in spreadsheet imports straight into Tirzing on the Import data page.

What have I lost?

The public twin of your “You've lost the equivalent of…” card. Type in how much you've lost, pick a category, and it builds the same shareable image: you can reroll for a different comparison, save the picture, or copy a link to it. Inside the app the card fills itself in from your logged weight instead of asking.

Before & after maker

The public version of the before/after image builder. It takes two photos, two weights and two dates, and produces the same branded image with the same automatic face blurring.