Trendline is an iPhone app that reads Apple Health. This guide is the manual half of that arrangement.
How do you add a weight reading to Apple Health?
In the Health app, the entry form lives under Body Measurements:
- Open the Health app.
- Tap Browse.
- Tap Body Measurements.
- Tap Weight.
- Tap Add Data in the top-right corner.
- Enter the reading, adjust the date and time if it wasn't just now, and tap Add.
That's the whole procedure (Apple documents the Add Data flow in Manage Health data on your iPhone; a mistyped entry can be deleted from the same screen via Show All Data → Edit). The path sits four levels deep, which is the only real friction — once you know where the form lives, entering a weigh-in is a routine, not a project.
Why a hand-entered reading is worth having
A manual entry is first-class in Apple Health: it carries a value, a timestamp, and a source (your iPhone) exactly like a measurement written by a scale's companion app, and every Health-reading app treats it with the same standing. That has a quiet, valuable consequence — your history stays in one place. Switch scale brands, retire an app, weigh in at the gym for a month: the record continues in Health regardless of which instrument produced each reading. Keeping the readings out of any single vendor's silo is the whole strategy, and hand entry is its universal fallback.
Who this is for
- Scales with no sync at all — a display-only bathroom scale is still a working instrument.
- Scales whose app is gone or broken — discontinued vendors, dead servers, delisted apps; the hardware still measures.
- Scales whose sync excludes you — some vendors sync only the main user's readings; everyone else in the household can enter theirs by hand.
- Gym, clinic, and travel weigh-ins — any number you can read, you can keep.
Optional: one-tap logging with Shortcuts
Apple's Shortcuts app can wrap this flow into a single button: a shortcut using the Log Health Sample action asks for a number and writes it to Health as a weight reading — people build exactly this and share the recipe (MacRumors forums). Put it on the Lock Screen or in a widget and the four-level path disappears entirely.
Body fat percentage works the same way
If your scale shows a body fat estimate on its display, that can be hand-entered too: Health → Browse → Body Measurements → Body Fat Percentage → Add Data. Lean body mass and height have the same treatment. Numbers Apple Health has no type for — body water, visceral fat — can't be entered in Health at all.
When Trendline launches, it will read your hand-entered weight, body fat, and lean mass history from Apple Health like any synced data — and will accept manual entries directly, including composition values Health has no type for.
Try the idea
A few weeks of hand-entered weigh-ins already contain a direction — even when the day-to-day numbers bounce, because variation is normal. Paste them into the free weight trend calculator and see the slower signal your entries have been building.
Sources
- Apple: manage Health data on your iPhone, iPad, or Apple Watch (adding and deleting manual entries)
- MacRumors forums: create a shortcut to add my weight to Apple Health
Path verified against iOS 26 on July 20, 2026. Apple revises the Health app; if a label moves, the destination to look for is the Weight page under Body Measurements.