Written against iOS 26, July 2026. Apple revises the Health app; the verification date above is the promise.
What Health shows for weight
Open Health → Browse → Body Measurements → Weight and you get a chart of your readings across day, week, month, six-month, and year views; tap any point for its exact value and date (Apple's guide). This is a faithful record: every reading, exactly as written, from every connected source. As a ledger, it's excellent — it's the reason we recommend Apple Health as the neutral home for your readings in the first place.
But a ledger displays observations; it doesn't interpret them. In the day-to-day views, the line simply connects your raw readings — the Tuesday spike from a salty dinner gets the same visual authority as three quiet weeks of change underneath it.
What the Trends feature is (and isn't)
Health does have a feature called Trends. It compares your recent longer-window averages (on the order of 90 days against the past year) across roughly twenty mostly activity- and vitals-oriented metrics — resting heart rate, sleep, cardio fitness and kin — and surfaces an arrow when a sustained shift appears; it needs months of history before it can say anything at all (MyHealthyApple's walkthrough). If you've gone looking for a weight trend there and come away empty-handed, that's the mismatch: Trends answers "has this vital drifted over months," not "is my weight moving, under this week's noise."
The missing reading
"Is this working?" is a statistical question about a noisy series. Answering it responsibly takes three things a raw chart doesn't do:
- Deliberate smoothing — a slower signal that a single odd morning can't yank around, because a reading can be accurate and still be noisy.
- Resistance without denial — repeated movement should register; one outlier shouldn't. The reading stays honest to the data instead of flattering it.
- Candor about sparse evidence — three readings in three weeks deserve "not enough to say," not a confident line. The exact math Trendline uses is public on the methodology page.
See your trend right now
The free weight trend calculator runs in your browser — paste your readings (from Health, a scale app, or a notebook) and it draws the slower signal next to the raw series. Nothing uploads; the contrast speaks for itself.
When Trendline launches, it will read your existing weight, body-fat, and lean-mass history directly from Apple Health — the full history that's already there — and keep the trend current with each new reading. Trendline is an iPhone app; Apple Health is the only account it needs.