Draw a line.
Stay under it.
Line Diet is the simplest weight tracker on the web. Set a goal, weigh in once a day, and the app turns green when you’re under the line and red when you’re over it. If you’re in the red, you’re on a diet today, but if you’re in the green, just don’t overdo it. No calorie counting, no food logs — just one rule.
Run it now in the browser, or add it to your home screen on your phone for a great app experience.
One rule. One line. One tap a day.
The Line Diet (also known as the bang-bang servo diet or Steve Ward diet) replaces willpower with a graph. The line tells you what to do at every meal.
- 01Set your goal
Pick a target weight and a target date. The app draws a straight line from today to then.
- 02Weigh in daily
Tap once in the morning. Your weight goes on the chart, right next to the line.
- 03Follow the rule
Under the line? Eat normally. Over the line? Eat light today. That’s it.
Everything you need.
Nothing you don’t.
When today’s weight is at or under the line, every surface goes calm green. When you’re over, the screen glows red. You know where you stand at a glance.
Your data lives in your browser. Add to home screen and the app launches in a tap — plane, gym, basement bathroom scale, no signal required.
Pick your unit once. Switch any time. The math is the same; the display follows you.
30-day window with the goal line, your weigh-ins, and an optional trend smoother. Tap a point to see the day.
There’s nothing to sign up for. Open the app and start.
Free forever. Pro if you want it.
The whole app is free. Pro adds an account so your weigh-ins move with you between devices — phone, laptop, the kitchen tablet.
Free
AlwaysTrack your weight against the line on any one device. Your data never leaves your browser.
- Daily weigh-ins, unlimited history
- Goal line + 30-day chart
- Theme that follows your status
- Offline-first, install to home screen
- No account, no email, no tracking
Pro
SyncOne account, every device. Your weigh-ins follow you instead of staying stuck on the browser you started in.
- Cloud sync across phone, tablet, and laptop
- Everything in Free, forever
- Less than a coffee. Cancel any time, keep your data.
Pro isn't ready quite yet. For now just start tracking like normal and your local data will move into your account when sync ships.
Questions, answered.
Do I need an account?
No. The free app stores everything in your browser — you can use it forever without signing up. Pro adds an optional account to sync your weigh-ins between devices.
What happens if I clear my browser?
On the free plan, your local data lives in your browser's application data, and disappears if you clear it. Export your history any time from Settings, or upgrade to Pro for automatic cloud backup.
Does this work on my phone?
Yes. Line Diet is built mobile-first. Open it in your browser, tap the share icon, then tap “Add to home screen” — it launches like a native app and works offline.
Why no calorie counting?
Because you already know what eating light looks like. The line is the only signal you need: under it, eat normal; over it, eat lighter today.
Is this the same as the old iOS / Android app?
Yes — this is a rebirth of the original Line Diet iOS and Android apps, rebuilt for the web so it runs everywhere — no app store, no install required.
Ready to draw the line?
Free, offline, no signup. You’ll be tracking in under a minute.
Open Line Diet