Your weight jumps. Your trend does not.

Trendcurve smooths your daily readings, shows the real change per week and works out when you will reach your goal.

Free on the App Store For iPhone · no account · 100% on device

Screenshots with sample data

How it works

Three steps, then ten seconds a day are enough.

1

Weigh in and log

Log your weight in seconds or let it be imported automatically from Apple Health. Several readings on one day are averaged into a single daily value.

2

Watch the trend

Instead of the daily value you look at the trend weight: the smoothed line through your readings, calculated with the method you pick. The 7-day change tells you where things are really heading.

3

Steer towards your goal

Decide whether you want to lose, gain or maintain, and how fast. Trendcurve turns your rate into a target date, puts planned next to measured and sets milestones along the way.

This is what Trendcurve looks like

Five looks inside the app: dashboard, forecast, logging, history and report.

See your real progress: dashboard with a trend weight of 75.5 kg, daily dots and the smoothed trend line.
When will you hit your goal: forecast with a target date and ten milestones down to the target weight.
Logged in three seconds: day detail listing every single reading, imported from Apple Health.
Identify trends at a glance: history list with daily value, trend weight and 7-day change per day.
Every step gets celebrated: forecast chart projected to the goal, plus the monthly report.

Why the scale lies (and the trend does not)

Your weight swings by up to two kilos from day to day: water, salt, meals, cycle, sleep. Anyone judging the daily number celebrates coincidence and despairs over coincidence. Trendcurve smooths your readings and shows the line underneath that actually matters.

  • Trend weight: the smoothed line through your daily values, method up to you
  • 7-day change: today's trend against the trend one week ago
  • Weekly rate: the slope of your trend line, the basis of every forecast

A single bad day moves your trend by a few grams. That is exactly the point.

Daily values Trend

Everything you need

Log, understand, keep going. Trendcurve brings the tools for that without burying you in numbers.

Trend weight & 7-day change

The smoothed line through your readings plus the change against last week. Daily values as dots, the trend as a line, switchable across 1 month, 3 months, 1 year and all time.

Pick your trend algorithm

Exponential smoothing by default, or a 7 or 14 day moving average, or double exponential smoothing. Under "Settings & more" each method comes with its pros and cons and today's trend value.

Forecast & target pace

From your weekly rate Trendcurve projects when you will reach your goal. Your target pace sits right next to it: planned against measured, plus the days you are ahead of or behind plan. If nothing is moving, the app names the reason instead of inventing a date.

Calorie budget from your trend

From height, year of birth and sex Trendcurve estimates your maintenance needs, optionally with active energy from Apple Health. Your measured weekly rate gives the current balance, your target pace the budget for the day. With Pro.

Patterns in your history

Plateau detection with an explanation when the trend barely moves for days. Plus your weekday pattern and the weekly rate 28 days before and after every trend marker. With Pro.

Milestones & progress photos

A ladder between your starting and target weight, every step you reach is celebrated. Progress photos carry the date and your trend weight and can be shared as a before and after comparison. With Pro.

Apple Health both ways

Trendcurve reads your body weight from Apple Health, at app start and regularly in the background. If you want, the app writes manual entries back; body fat and waist run in both directions as soon as you turn them on.

Balance & monthly reports

How much your trend has changed over 7, 30 and 90 days and in total. Plus every month in numbers: change, measured days, range and longest streak.

Body measurements & BMI

Waist, hip, chest or body fat as a second metric, each with its own trend over a 28-day window, plus a weekly reminder at a time you choose. BMI is optional and stays off until you turn it on.

Trend markers & outliers

Record holidays, illness or a change of diet as markers, and with a trend restart the calculation begins again on that day. Single readings can be ignored: they stay visible but no longer count towards trend and rate.

Reminders & streak

Times and weekdays are up to you. The smart reminder stays quiet on days you have already weighed in, and streak protection saves your run.

Units, widgets & dark mode

Kilograms, pounds or stones, height and measurements in centimetres or feet and inches. Plus trend, 7-day change and a mini chart on the home and lock screen, light or dark and a dashboard whose cards you can reorder.

Trend weight & 7-day change

The smoothed line through your readings plus the change against last week. Daily values as dots, the trend as a line, switchable across 1 month, 3 months, 1 year and all time.

Pick your trend algorithm

Exponential smoothing by default, or a 7 or 14 day moving average, or double exponential smoothing. Under "Settings & more" each method comes with its pros and cons and today's trend value.

Forecast & target pace

From your weekly rate Trendcurve projects when you will reach your goal. Your target pace sits right next to it: planned against measured, plus the days you are ahead of or behind plan. If nothing is moving, the app names the reason instead of inventing a date.

Calorie budget from your trend

From height, year of birth and sex Trendcurve estimates your maintenance needs, optionally with active energy from Apple Health. Your measured weekly rate gives the current balance, your target pace the budget for the day. With Pro.

Patterns in your history

Plateau detection with an explanation when the trend barely moves for days. Plus your weekday pattern and the weekly rate 28 days before and after every trend marker. With Pro.

Milestones & progress photos

A ladder between your starting and target weight, every step you reach is celebrated. Progress photos carry the date and your trend weight and can be shared as a before and after comparison. With Pro.

Apple Health both ways

Trendcurve reads your body weight from Apple Health, at app start and regularly in the background. If you want, the app writes manual entries back; body fat and waist run in both directions as soon as you turn them on.

Balance & monthly reports

How much your trend has changed over 7, 30 and 90 days and in total. Plus every month in numbers: change, measured days, range and longest streak.

Body measurements & BMI

Waist, hip, chest or body fat as a second metric, each with its own trend over a 28-day window, plus a weekly reminder at a time you choose. BMI is optional and stays off until you turn it on.

Trend markers & outliers

Record holidays, illness or a change of diet as markers, and with a trend restart the calculation begins again on that day. Single readings can be ignored: they stay visible but no longer count towards trend and rate.

Reminders & streak

Times and weekdays are up to you. The smart reminder stays quiet on days you have already weighed in, and streak protection saves your run.

Units, widgets & dark mode

Kilograms, pounds or stones, height and measurements in centimetres or feet and inches. Plus trend, 7-day change and a mini chart on the home and lock screen, light or dark and a dashboard whose cards you can reorder.

Trend weight & 7-day change

The smoothed line through your readings plus the change against last week. Daily values as dots, the trend as a line, switchable across 1 month, 3 months, 1 year and all time.

Pick your trend algorithm

Exponential smoothing by default, or a 7 or 14 day moving average, or double exponential smoothing. Under "Settings & more" each method comes with its pros and cons and today's trend value.

Forecast & target pace

From your weekly rate Trendcurve projects when you will reach your goal. Your target pace sits right next to it: planned against measured, plus the days you are ahead of or behind plan. If nothing is moving, the app names the reason instead of inventing a date.

Calorie budget from your trend

From height, year of birth and sex Trendcurve estimates your maintenance needs, optionally with active energy from Apple Health. Your measured weekly rate gives the current balance, your target pace the budget for the day. With Pro.

Patterns in your history

Plateau detection with an explanation when the trend barely moves for days. Plus your weekday pattern and the weekly rate 28 days before and after every trend marker. With Pro.

Milestones & progress photos

A ladder between your starting and target weight, every step you reach is celebrated. Progress photos carry the date and your trend weight and can be shared as a before and after comparison. With Pro.

Apple Health both ways

Trendcurve reads your body weight from Apple Health, at app start and regularly in the background. If you want, the app writes manual entries back; body fat and waist run in both directions as soon as you turn them on.

Balance & monthly reports

How much your trend has changed over 7, 30 and 90 days and in total. Plus every month in numbers: change, measured days, range and longest streak.

Body measurements & BMI

Waist, hip, chest or body fat as a second metric, each with its own trend over a 28-day window, plus a weekly reminder at a time you choose. BMI is optional and stays off until you turn it on.

Trend markers & outliers

Record holidays, illness or a change of diet as markers, and with a trend restart the calculation begins again on that day. Single readings can be ignored: they stay visible but no longer count towards trend and rate.

Reminders & streak

Times and weekdays are up to you. The smart reminder stays quiet on days you have already weighed in, and streak protection saves your run.

Units, widgets & dark mode

Kilograms, pounds or stones, height and measurements in centimetres or feet and inches. Plus trend, 7-day change and a mini chart on the home and lock screen, light or dark and a dashboard whose cards you can reorder.

PRO

Trendcurve Pro - when you want to know exactly

Logging, units, trend weight, the algorithm you pick and history stay free forever. Pro opens up the analysis.

Feature Free Pro
Log weight, Apple Health, import
Units kg, pounds or stones
Trend weight, 7-day change, history
Pick your trend algorithm
Ignore a reading
Chart ranges 1 & 3 months plus 1 year & all time
Goal, progress & target pace
Forecast with target date, planned vs measured
Calorie budget from your trend
Patterns: plateau, weekdays, markers
Milestones
Balance & monthly reports
Body measurements
Progress photos
Trend markers & restart
Share trend as an image
Export CSV/JSON & import
iCloud backup
Widgets Small home widget plus medium & lock screen
Reminders One time, smart, measurement reminder Several times & streak protection
Price Free Monthly, yearly or one time

Pro is available as a monthly or yearly subscription and as a one time purchase without a subscription. Current prices are shown in the app and on the App Store.

Discover Pro

Your data stays with you

Trendcurve has no server and no account. All readings live locally on your iPhone. There is no analytics, no tracking and no advertising ID. Only if you switch on the iCloud backup does a copy end up in your own iCloud account, which we cannot access.

Frequently asked questions

Answers to the most important questions about Trendcurve.

Your weight fluctuates from day to day by up to 1 to 2 kg, due to water, salt or meals. The trend weight smooths these fluctuations and shows where things are really heading. The default is exponential smoothing, where recent readings count for more than older ones; alternatively Trendcurve uses the average of the last 7 or 14 days or double exponential smoothing.

Exponential smoothing is the default and a good compromise between calm and responsive. The 14 day average is the calmest and lags the most, the 7 day average reacts faster but is more restless, and double exponential smoothing also takes the direction into account and bridges gaps. Under "Settings & more → Trend algorithm" each method comes with its pros and cons and today's trend value. You can switch at any time, your readings stay exactly as they are.

The change compares your trend weight today with your trend weight seven days ago. It equals the moving average of the daily change over a week, so you can see at a glance whether you are heading in the right direction.

A straight line is fitted through the trend values of the last 14 days. Its slope is your weekly rate. From that Trendcurve derives when you will reach your goal or the next milestone, assuming things continue as they did over the last two weeks. If your trend barely moves or runs away from the goal, Trendcurve names the reason instead of a date. If you have set a target pace, planned and measured rate sit side by side, together with the days you are ahead of or behind plan.

Height, year of birth and sex give your basal metabolic rate according to Mifflin-St Jeor, and your activity factor or the active energy from Apple Health turns that into your maintenance needs. Your measured weekly rate shows what your balance actually looks like right now, and your target pace gives the budget for the day, calculated with 7,700 kcal per kilogram. All values are estimates and do not replace nutritional advice. The calorie budget is part of Pro.

Enable the import under "Settings & more → Apple Health". Trendcurve then reads all body weight entries from Health: at app start, when returning to the app and regularly in the background, and notifies you about newly imported entries. On top of that you can switch on writing back: manual entries then land in Health, and edits and deletions follow. Body fat and waist run in both directions as soon as you turn those measurements on.

All measurements of a day, whether manual, imported or from Health, are averaged into one daily value. In the history you see this daily value, the trend weight and the change.

Yes. Mark it as ignored in the history: the value stays visible, struck through and with an eye icon, but no longer counts towards the daily value, the trend, the rate, the balance or the monthly report. This works for entries from Apple Health too and can be undone at any time.

Yes. Under "Settings & more → Units" you switch between kilograms, pounds and stones, and between centimetres and feet/inches for height and body measurements. The default follows your region, so pounds in the US and stones in the UK and Ireland. Everything is stored in kilograms internally, so switching only changes how your existing values are displayed.

Logging weight, units, the trend with the algorithm you pick, the 7-day change, history, your target pace, Apple Health, reminders and export stay free. Pro unlocks the forecast with target date, the calorie budget, patterns such as plateaus and weekdays, milestones, balance, monthly reports, body measurements, progress photos, trend markers, long chart ranges, sharing as an image, the iCloud backup and the larger widgets. Pro is available as a monthly or yearly subscription and as a one time purchase.

Only if you want it to be. By default all data stays on your device; Trendcurve has no server and no account. Optionally you can enable an automatic backup to your own iCloud account under "Export, backup & import" for switching devices. We have no access to it.

Under "Settings & more → Export, backup & import" you can export your weight as CSV or everything as a JSON backup and import both again. With the iCloud backup enabled, Trendcurve offers to restore automatically after a reinstall. CSV exports from Happy Scale, Libra or openScale can be imported too.

Markers let you record events such as a holiday, illness or a change of diet in your history. If you enable "restart trend", the trend calculation starts over on that day: older values no longer pull the trend along, and rate and comparisons begin anew. Your history is fully preserved. With Pro, every marker also shows the weekly rate for the 28 days before and after it.

Shots from the camera or your library, stored with the date and your trend weight. Any two of them can be put side by side as a before and after comparison and shared as an image. The photos stay locally on your iPhone and are included in the JSON export. Progress photos are part of Pro.

Yes, optionally. Under "Settings & more → Body measurements" you choose which measurements you want to record. Each one gets its own history with trend and comparison; from waist and hip Trendcurve also calculates the waist to hip ratio. Body fat and waist can be exchanged with Apple Health, and a weekly reminder at a day and time you choose skips itself when you have just measured. Weight remains the core of the app.

Yes. Press and hold the home or lock screen, tap "+" and search for Trendcurve. There are small and medium home widgets with trend, 7-day change, streak and a mini chart, as well as lock screen widgets. A tap opens the app.

Open the Customer Center under "Settings & more → Manage subscription & purchases". There you can see your subscription, change or cancel it and restore earlier purchases. Billing runs through the App Store. If you bought Pro as a one time purchase, it stays active permanently.

See where things are really heading

Download Trendcurve for free and turn a number that jumps every day into a line you can trust.

Download for free