Stay with TrendWeight: Withings scale or the manual weight log
TrendWeight is still free and open source, and it is not shutting down. Withings scales, the manual weight log, and the API still work. It does not receive new Fitbit weigh-ins.
What changed with TrendWeight and Fitbit
Google turned off the old Fitbit Web API
Google's developer page says support for the legacy Fitbit Web API ended on September 30, 2026. On November 2, 2026, Google turned that API and the Fitbit OAuth endpoints off. Requests now return HTTP 410 Gone.
Why TrendWeight isn't moving to the Google Health API
Developer Erv Walter says TrendWeight won't support the Google Health API directly. More than 100 Fitbit users would mean Google verification and a yearly third-party security audit, which he says is not viable for a free spare-time project.
Your TrendWeight history stays
His November 2 update says Fitbit syncing is now disabled. Existing data stays unless you delete it, and deletion is permanent. No new Fitbit accounts can be connected. TrendWeight isn't going anywhere. Download a copy of your data.
Your options (free first)
Start a new log in Life Forecast
Life Forecast is a free installable web app. Log weight in kg or lb, plus calories, sleep, and workouts, by hand. The chart shows daily dots and a smoothed 7-day average. The estimated goal date is a straight-line fit through the last 30 days of weigh-ins (at least 3) and recalculates as you log. There is no Fitbit sync, no Google Health sync, no Apple Health sync, and no import. You start a fresh log. Keep TrendWeight, or its download, for your past.
iPhone and Apple Health: Trendline (paid)
Trendline is a paid iPhone app that reads Apple Health: $0.99/week, $3.99/month, $10.99/year, or $34.99 lifetime. It describes a Fitbit Aria path through the Google Health iPhone app into Apple Health. Life Forecast does not sync with Apple Health.
TrendWeight vs Life Forecast vs Trendline
Feature
TrendWeight
Life Forecast
Trendline
Price
Free (trendweight.com/about). "Will always be free": Unknown
Free
$0.99/week · $3.99/month · $10.99/year · $34.99 lifetime (per Trendline)
Runs on
Website in a browser (about page). Native app: Unknown
Installable web app
iPhone app (per Trendline)
New Fitbit weigh-ins
No. Fitbit sync disabled November 2, 2026 (developer)
No Fitbit sync
Indirect: via Google Health iPhone app → Apple Health (per Trendline)
Other inputs
Withings sync, manual weight log, API (developer)
Manual logging of weight, calories, sleep, and workouts. No import.
Manual + Apple Health (per Trendline)
Import past history
History already in TrendWeight stays. CSV download (GitHub README)
No import
Unknown
Trend
Exponentially weighted moving average, 10% of the way toward today's weight (TrendWeight math)
Smoothed 7-day average on the chart, plus daily dots
"Statistical trend with explicit uncertainty" (self-described)
Goal date
Unknown (not stated on trendweight.com/about)
Estimated date from a straight-line fit through the last 30 days of weigh-ins (at least 3)
Goal forecast (self-described)
Maintenance
Goal range a bit above and below the goal (about page)
Free maintenance mode: default band ±1.5%. Example at 75 kg / 165 lb: about ±1.1 kg / ±2.5 lb. Days-in-band streak and a drift notice after a week outside the band.
"Maintain" phase (self-described)
Units
kg or lb (settings; kg support described on the TrendWeight blog)
kg or lb
Unknown
Open source
Yes (public GitHub repository)
—
Unknown
Checked November 13, 2026. "Unknown" means we did not confirm that cell on TrendWeight's about page or in the sources linked below. How the forecast works.
Moving to Life Forecast in 3 steps
- Note your current trend weight and your goal, in kg and in lb, from TrendWeight.
- Set that goal in Life Forecast.
- Weigh in each morning. Before 3 weigh-ins the card says "Based on your plan — will refine after 3 weigh-ins". After 3 weigh-ins within 30 days, the date switches to your own trend. Confidence moves toward medium around 7 weigh-ins and high around 14 with a clear trend. See how the forecast works.
At your goal: maintenance mode
Reached your goal? Maintenance mode is free. It keeps you in a band around the goal. The default width is ±1.5%. As an example, at 75 kg (165 lb) that is about ±1.1 kg (±2.5 lb). It counts days inside the band and flags drift after a week outside the band.
FAQ
Why did TrendWeight stop getting my Fitbit weigh-ins?▼
Google retired the legacy Fitbit Web API that TrendWeight used. Support ended September 30, 2026, and Google turned the API off on November 2, 2026. TrendWeight's developer says Fitbit syncing is now disabled and that TrendWeight won't support the replacement Google Health API directly, because of its yearly audit requirements.
Is TrendWeight shutting down?▼
No. Its developer says TrendWeight "isn't going anywhere" and existing data stays in your charts unless you delete it. Only the Fitbit connection has ended, and new Fitbit accounts can't be connected. You can keep using TrendWeight with a Withings scale, its manual weight log, or its API. Download a copy of your data.
Can I import my TrendWeight or Fitbit history into Life Forecast?▼
No. Life Forecast has no import and no Fitbit sync, so you start a new log. Keep TrendWeight or your data download for your past weigh-ins. After 3 morning weigh-ins within 30 days, Life Forecast estimates a goal date from your own trend.
Is Life Forecast free?▼
Yes. Life Forecast is a free, installable web app. You log weight, calories, sleep and workouts in kg or lb, see a smoothed 7-day average, and get an estimated goal date that recalculates as you log. At your goal, a free maintenance mode tracks days inside a band around it.
Which free app keeps my weight trend and goal date?▼
TrendWeight itself, if you switch to Withings or type weights into its weight log. If you'd rather start fresh, Life Forecast is free, shows a smoothed trend and an estimated goal date, and has a maintenance mode. Neither reads new Fitbit weigh-ins.
Free · no credit card
Start a free log — log this morning's weight in kg or lb and see your trend build.
Not affiliated with TrendWeight, Fitbit or Google. Sources checked November 13, 2026: About the Google Health API, Erv Walter, Fitbit, Google Health, and What's Next, TrendWeight about, TrendWeight kg support, TrendWeight on GitHub, Trendline. Comparing an iPhone trend app? See the Happy Scale alternative.