Track your CdA for free.
Upgrade when you want the long-term trend.
Link your device and every outdoor ride gets a CdA estimate automatically; free accounts see the latest 5. For your converged CdA, 90-day trend, outlier explanations and equipment comparison, subscribe to CdA Pro. Preparing for just one race? Buy that race.
Free
Sign up for a free account, no credit card needed
US$0
Unlimited plans and reruns
- CdA for every ride: link your device or upload FIT files and each ride is estimated and saved; see the latest 5
- 211 real courses: most IRONMAN races plus Challenge, with elevation profile, distance and climbing, course intel and speed score
- Six-level power plan: CdA looked up from height, weight and position, then calculated section by section with the course elevation; unlimited recalculation when you change parameters
- No race-day weather or wind, no tire pressure numbers, no export files: those three are paid
CdA Pro
For athletes who track aero like any other training number
US$19
Monthly subscription
- History that builds up: several records combined with the more accurate ones counting for more, giving a CdA with its error range that gets better the more you test; drafting, punctures, the wrong bike type and a slipping position are all flagged and explained in plain language
- Any ride, any course, dragged in by the batch: training rides, outdoor rides, race files; every file gets estimated and filed on its own
- Equipment comparison: matching setup labels are pooled and compared for you, with the difference converted straight into seconds over 90 km
- Full race planning: race-day weather, tire pressure and all three outputs on every course, as often as you like, built on your measured CdA
Race Pass
For the athlete preparing for just one race
US$15
One race · that course × that year
- Everything in Free, plus (for that course × that year):
- Race-day weather and wind, section by section: hourly forecast or measured historical data, with headwind sections bumped up a level automatically
- Three outputs: head unit course file (.FIT), Zwift file, race card
- Work out your CdA from a FIT file: your own number (with an error range) instead of a typical look-up value, applied straight to this plan
Coach plan
For coaches with a few athletes, or a whole team
Coach Team
US$69
Monthly subscription
Unlimited linked athletes: every athlete you link gets CdA Pro
Subscribe to Coach Team →Split across a squad it costs far less than a CdA Pro subscription per athlete
- Everything in CdA Pro, plus:
- Invite athletes to link up: they accept with their own account, and from there you both manage the numbers, the CdA history and the race plans; linked athletes get CdA Pro automatically
- Plans on every course off your athletes' measured CdA, unlimited (211 full-distance and 70.3 courses in the library)
- Athlete CdA management: drag a batch of FIT files into an athlete's profile, write the converged value in one click, and it loads into their plans from then on
Subscriptions can be upgraded, downgraded or canceled any time (Manage subscription, in Account settings). Cancel and the plans and raw CdA files you have already built stay put, so resubscribing picks up where you left off.
Plan comparison
| Feature | Free | CdA Pro | Race Pass | Coach / Team |
|---|---|---|---|---|
| CdA aero analysis | ||||
| CdA solved from a FIT file | Latest 5 rides | Any course | That race's plan | Any course |
| History filed automatically, original files kept | Saved, opens on upgrade | ✓ | — | ✓ |
| Several records combined (with error range) | — | ✓ | — | ✓ |
| Bike type grouping · outliers · in-race drift detection | — | ✓ | — | ✓ |
| Whole history re-estimated when the engine is upgraded | — | ✓ | — | ✓ |
| Setup comparison + deep analysis on any record | — | ✓ | — | ✓ |
| Batch drag-and-drop upload | — | ✓ | — | ✓ |
| Pacing plans | ||||
| 211 course elevation profiles · course intel · speed rankings | ✓ | ✓ | ✓ | ✓ |
| Six-level power plan (CdA from a lookup: height · weight · position, plus course elevation) | ✓ Unlimited | ✓ | ✓ | ✓ |
| Race-day weather and wind, segment by segment | — | ✓ | That course × that year | ✓ |
| Tire pressure | — | ✓ | That course × that year | ✓ |
| Three outputs (head unit course file · Zwift · race card) | — | ✓ | That course × that year | ✓ |
| Plans off your measured CdA | — | ✓ | That course × that year | All courses, unlimited |
| Post-race comparison | — | ✓ | ✓ | ✓ |
| Coach features | ||||
| Athlete profiles + one-click load into plans | — | — | — | ✓ |
| Athlete CdA history (link athletes, batch upload, write to profile) | — | — | — | ✓ |
| Post-race CdA written back to the athlete profile in one click | — | — | — | ✓ |
| Invite athlete accounts to link · linked athletes get CdA Pro | — | — | — | Coach 4 · Team unlimited |
FAQ
Which CdA numbers can a free account see?
Link your device or upload FIT files, and every outdoor ride with power gets a CdA estimate and is saved. A free account sees single-ride values and error ranges for the latest 5 rides. The converged value from many rides, the 90-day trend, outlier reasons, gear comparison, and planning races with your measured CdA are CdA Pro features. When you upgrade, the rides already saved open up at once.
How far does the free plan actually go?
Once you have a free account, pick a course (or upload a GPX), enter your FTP, height, weight and position, and the system works out a six-level power plan, a finish time prediction and a climbing check, section by section from the course elevation, as often as you like. The free version does not include race-day weather and wind converted section by section, tire pressure advice, or the output files (course file, Zwift, race card); those come with a Race Pass and the paid plans. CdA in the free version is looked up from your position (about 15% out); once you pay, you can work it out properly from your own race file.
What kind of file do I need to estimate CdA?
An outdoor ride FIT file with GPS, power, speed and elevation (trainer files will not work). Steady cruising on flat road for 20 minutes or more reads best; no drafting, and the position and equipment have to match what you race. No file that fits? Follow the calibration ride guide and one ride gives you one.
What is the difference between one estimate and the subscription?
A single estimate only tells you the CdA for that day and that file. With a subscription, every upload is stored and they are worked out together: the more reliable records count for more, single-day weather errors and position wobbles cancel each other out, the error range narrows as records build up, and you end up with a number steadier than any single test. On top of that, the difference before and after you change your position or your gear is visible at a glance on the trend chart.
When does a Race Pass expire?
You buy “that course × that year”. Recalculate as often as you like within the year, and the post-race comparison is included. For the same race next year, buy it again.
Do I pay again to change parameters?
No. For the same course and year, change FTP, weight, date, weather and tires as often as you like, and re-download the output files any time.
Can I upgrade Coach to Team?
Upgrade from Coach any time; the difference is prorated
Does my history disappear when the subscription ends?
No. Records and original files stay, and full access comes back when you renew. You can also delete your own data record by record, any time.
Track for free first. Decide once you see the trend.
No credit card to sign up. Link your device once and every outdoor ride gets its CdA automatically.
Start tracking my CdA for free