GroupWeight is a private, encrypted weight and body measurement tracker. Your actual weight figures are encrypted in your browser before they ever reach the server — nobody, including the site administrator, can see your real numbers. Only you can decrypt and read your data.

Getting started
Creating your account
Your administrator will set up your account and give you a temporary password. On first login you will be asked to change it immediately. Choose something strong — at least 8 characters. Because your data is encrypted using a key derived from your password, there is no way to recover your entries if you forget it. Export your data regularly as a backup.
Logging in
You can log in with either your username or your email address. On iPhone, tap the key icon above the keyboard to save your credentials to Apple Passwords so you never need to type them again.

The Tracker tab
Logging an entry
Tap 📊 Tracker and use the Log an entry form. Enter the date (defaults to today) and your weight. You can also record body measurements — waist, neck, chest, hips, thighs, biceps, calves, and body fat % — though these are all optional. Add a note to record how you are feeling or any relevant context. Tap Save entry.
You can only have one entry per date. Saving a second entry for the same date overwrites the first.
History table
Your entries appear in the table below the log form, newest first. The second column changes depending on which metric is selected in the chart above — switch to % Loss to see your cumulative percentage change alongside each entry. Use the ✏️ button to edit an entry or ✕ to delete it.
Progress stats
The stats row shows your total entries, latest weight, total change, change in the last 7 days, active weeks streak, and BMI (requires height to be set in Settings). The total change and 7-day change also show as a percentage of your starting weight.
Goal progress bar
If you have set a target in Settings, a private progress bar appears showing how far along you are towards your goal, the amount still to go, and days remaining if you set a target date. This is never shared with anyone.
Charts
The chart shows your data over time. Use the metric dropdown to switch between:
⚖️ Weight — change from your first entry, with a 7-day moving average
📉 % Loss — cumulative percentage lost from your start, with a 7-day average
📊 BMI — body mass index over time (requires height)
📏 Measurements — any body measurement you have recorded
Use the range buttons (1M, 3M, 6M, 1Y, All) to zoom in. If you have set a target, a dashed amber line shows your target on both the weight and % loss charts. The chart defaults to whichever metric matches your goal type — weight chart for a weight target, % loss chart for a percentage target.

Settings
Display units
Choose Stones & Pounds or Kilograms for weight, and cm or inches for measurements. Changing units automatically converts any target weight you have already entered.
Recording start date
By default, % loss calculations and charts use your oldest entry as the starting point. If you want to restart your progress tracking without deleting old entries — for example after reaching a goal and starting a new one — set a new start date here. Everything before that date is kept but ignored for percentage and target calculations.
Group leaderboard sharing
Choose what other group members can see about your progress:
Weight change (Δ) — others see your weight delta (how much you have lost or gained) but never your actual weight.
% loss only — others see only your percentage lost. Your actual weight change figure is never sent to the server in this mode, making it impossible for anyone to calculate your true weight.
Changing this setting takes effect on the leaderboard immediately — your existing entries are updated automatically in the background.
Personal goal
Set a private target that only you can see. Choose between:
Target weight — enter a goal weight in your chosen unit (e.g. 11.7 for 11 stone 7 pounds, or 74.5 for kg). When entering stones and pounds, type the stones and pounds separated by a dot — for example 11.7 means 11st 7lb, and 11.10 means 11st 10lb.
Target % loss — enter a percentage to lose from your start weight (e.g. 10 for 10%).
Switching between the two types automatically converts your existing target. Optionally add a target date to see a countdown.
Height
Enter your height to unlock BMI tracking. Height is saved to your account and syncs across all your devices.

Groups tab
Joining a group
Ask your group administrator for the invite code, enter it in the Join a group box, and tap Join. Some groups require approval from the owner before you are admitted.
Creating a group
Tap Create a group, give it a name, and optionally set a start date (entries before this date are excluded from leaderboard calculations). Enable Require approval if you want to vet new members, or Anonymous leaderboard to hide real names and show handles instead.

Leaderboard tab
Select a group to see the leaderboard. Members are ranked by their chosen sharing metric — weight change or % loss. Members using % loss show a small % badge next to their name. Use the sort dropdown to rank by weight change, % loss, individual measurements, or streak. Members who have not opted into a particular metric are sorted to the bottom of that column.
The leaderboard only ever shows changes — never anyone’s actual weight.

Profile tab
Update your display name, email address, or username. Your display name is what appears to other group members on the leaderboard.

Tools tab
Export
Three export options are available:
Export entries (CSV) — all your weight and measurement entries in a spreadsheet-compatible file.
Export profile & settings (JSON) — your preferences, height, targets, and units.
Export everything — both files at once.
Export your entries regularly. Because your data is encrypted with your password, there is no server-side recovery option if your account is lost.
Import
Import a previously exported CSV to restore your entries (duplicate dates are skipped), or import a profile JSON to restore all your settings on a new device.

Security (Profile → Security tab)
Two-factor authentication
Enable 2FA with any authenticator app (Google Authenticator, Authy, 1Password, etc.) for an extra layer of security. Once enabled, you will be asked for a 6-digit code after entering your password.
Change password
Important: changing your password re-encrypts all your entries with the new password. Do not close the browser while this is in progress. If you have a large number of entries it may take a few seconds.
Active sessions
See every device currently logged in to your account. Your current session is marked. You can revoke individual sessions, select multiple to revoke at once, or tap Revoke all other sessions to sign out everywhere else in one tap.