Tare - Weight Trend

Your weight swings a kilo a day from water and salt. Tare smooths it away and shows the trend underneath, as a range, never a date. Local only.

Your weight on any one morning is mostly water, salt and what you ate the day before. It can swing a kilo or two between days when nothing about your body fat has changed. Tare smooths that swing away and shows you the trend underneath — the number worth comparing with last month.

What it does

• The trend, large, as the one number on the home screen. Today's reading is a caption under it, and can be hidden entirely.
• The rate over the last four weeks, with its uncertainty stated rather than hidden: "somewhere between 0.30 and 0.69 kg a week".
• A forecast to your goal as a date range, never a single date. The chart draws it as a cone that widens the further ahead it goes, because that is the honest shape of a forecast.
• Milestones as dated records, measured on the trend, so one dry morning cannot pass one.
• A maintenance range once you arrive, with drift reported only after seven days outside it — and reported in the same words whether you drift above or below.
• Notes on the chart, with quick words for the things that swing a reading: travel, unwell, period, salty meal, alcohol, poor sleep, fasting.
• A daily reminder that stays quiet on days you have already weighed in.
• Apple Health import, so readings from a connected scale or another app arrive on their own. Weight and height only; nothing is ever written back.
• A PIN lock that shows nothing behind it.
• Kilograms, pounds, or stones and pounds. Light and dark. Large text.
• A "How this works" page that explains the maths in plain words, with the real numbers.

What it will not do

It will not count how many days in a row you have weighed in, award you anything, or cheer. It will not hold up your lowest reading of the week as a number to beat. It will not describe weight below your goal as progress, and it will not accept a goal that puts you underweight. It will not mention a gap in your weigh-ins except as a fact.

Your data

Everything stays on your iPhone. There is no account, no server, no analytics, no ads, and the app makes no network connections at all. Your weigh-ins are included in your iPhone's iCloud backup, and you can export them as a plain CSV file whenever you like.