From one race
to aero gains you can see
Log in with a free account and you can build a six-level power plan. Three paid plans cover three needs: racing one event, turning CdA into a long-term data asset, or coaching a whole team.
Invite-only beta · all features free during the beta · ask your coach for an invite codeFree
Log in with a free account and start calculating. During the beta, ask your coach for an invite code
NT$0
Unlimited calculations
- 208 real courses: elevation profiles, distance and climbing, course intel and speed score for the full IRONMAN series plus Challenge
- Global course speed rankings: full-distance and 70.3 groups, filter by region and month
- Six-level power plan: CdA looked up from height, weight and position, calculated segment by segment with course elevation; change parameters and recalculate as often as you like
- Segment power chart, level breakdown, segment table, climbing ability check
- Works with your own GPX too
- Parameters and plans saved automatically to My plans
- Does not include race-day weather and wind conversion, tire pressure advice or export files; those three are paid features
Race Pass
Athletes preparing for one race
NT$399
One race · that course × that year
- Everything in Free, plus (for that course × that year):
- Race-day weather and wind converted segment by segment: hourly forecast / historical same-date weather, headwind segments bumped up a level automatically
- Three outputs: head unit course file (.FIT), Zwift file, race card
- Tire pressure advice (by tire width, casing, road surface and predicted average speed)
- Your CdA solved from a FIT file: from ±15% by lookup down to about ±2%, applied straight to that race's plan
- Post-race comparison: plan vs. actual, segment differences, CdA closed-loop check
CdA Pro
Athletes who want to treat aero as a training metric
NT$599 /month
Monthly subscription
- Race-day weather, tire pressure and all three outputs on every course, unlimited, plus:
- Estimate on any course, batch upload: drag in training rides, outdoor rides and race files in bulk; each file is estimated and stored automatically
- Converging history: multiple records weighted by accuracy converge into a CdA with a confidence band, more accurate with every test; drafting, flat tires, wrong bike type and position slipping are flagged automatically and explained in plain language
- Equipment comparison: setup labels merged and compared automatically, with the difference converted straight into seconds over 90K; My routes lets you simulate it on your own time trial course
- Deep analysis per record: plain-language summary card plus virtual elevation and rolling CdA curve, so you can see what happened in every record
- Apply the converged value in one click to any pacing plan
- Original files are kept; when the engine is upgraded your whole history is re-estimated automatically, so your data asset never depreciates
Coach plan
Coaches and teams with multiple athletes
NT$899 /month
Monthly subscription
- Everything in CdA Pro, plus:
- Plans on every course using athletes' measured CdA, unlimited (208 full-distance and 70.3 courses in the library)
- Athlete profiles: store parameters, load them into a plan in one click
- Athlete CdA management: drag batches of FIT files into an athlete's profile, write the converged value in one click, loaded into plans automatically
- Post-race comparison re-estimates CdA and writes it back to the athlete profile in one click
- Plan history filed by athlete, load and recalculate
All three plans are fully open during the beta. When paid plans go live, the plans and CdA history you have already built are kept in full.
How far off is it from a wind tunnel? Under 1%.
In January 2026, an athlete with an 8:17 full-distance finish had his equipment measured in the wind tunnel at the HKUST Aerodynamics and Acoustics Facility (AAF). We ran his IRONMAN Hamburg race file from six months later through AeroPacer, same equipment setup as race day. The two numbers speak for themselves:
Note: the wind tunnel value is a single-point measurement at 0° yaw in a fixed position; the race estimate covers 4.3 hours of real-world dynamics (position changes, road surface, wind), so the two were never going to match exactly. A difference under 1% means the two methods confirm each other. The accuracy of a single estimate depends on file quality (flat, little drafting, steady cruising is best); the subscription's multi-record convergence keeps shrinking the uncertainty as data accumulates.
Plan comparison
| Feature | Free | Race Pass | CdA Pro | Coach plan |
|---|---|---|---|---|
| Pacing plans | ||||
| 208 course elevation profiles · course intel · speed rankings | ✓ | ✓ | ✓ | ✓ |
| Six-level power plan (lookup CdA: height · weight · position, plus course elevation) | ✓ Unlimited | ✓ | ✓ | ✓ |
| Race-day weather and wind converted per segment | — | That course × that year | ✓ | ✓ |
| Tire pressure advice | — | That course × that year | ✓ | ✓ |
| Three outputs (head unit course file · Zwift · race card) | — | That course × that year | ✓ | ✓ |
| Plan with your measured CdA | — | That course × that year | ✓ | All courses, unlimited |
| Post-race comparison | — | ✓ | — | ✓ |
| CdA aero analysis | ||||
| CdA solved from FIT file | — | That race's plan | Any course | Any course |
| History stored automatically + original files kept | — | — | ✓ | ✓ |
| Multi-record weighted convergence (± confidence band) | — | — | ✓ | ✓ |
| Bike type grouping · outliers · in-race drift detection | — | — | ✓ | ✓ |
| Whole history re-estimated on engine upgrades | — | — | ✓ | ✓ |
| My routes + equipment time simulation | — | — | ✓ | ✓ |
| Equipment setup comparison + deep analysis per record | — | — | ✓ | ✓ |
| Batch drag-and-drop upload | — | — | ✓ | ✓ |
| Coach features | ||||
| Athlete profiles + load into plans | — | — | — | ✓ |
| Athlete CdA history management (link athletes, batch upload, write to profile) | — | — | — | ✓ |
| Post-race CdA written back to athlete profile in one click | — | — | — | ✓ |
FAQ
How far does the free plan actually go?
Log in with a free account, pick a course (or upload a GPX), enter FTP, height, weight and position, and the engine calculates a six-level power plan, finish time prediction and climbing ability check from the course elevation, segment by segment, as often as you like. The free plan does not include race-day weather and wind conversion, tire pressure advice or export files (head unit course file, Zwift, race card); those belong to the Race Pass and the paid plans. On the free plan, CdA comes from a position lookup (±15%); paid plans use your own race file to get it right.
What kind of file do I need to estimate CdA?
An outdoor ride FIT file with GPS, power, speed and elevation (trainer files do not work). Steady cruising on flat roads for 20 minutes or more is most accurate; no drafting, and position and equipment must match what you race with. No suitable file? Follow the calibration ride guide and one ride will give you one.
What is the difference between a single estimate and the subscription?
A single estimate gives you the CdA for that day and that file. The subscription stores every upload as history and converges them weighted by window count × recency, so weather errors and position wobble in single records cancel each other out, the confidence band narrows as records accumulate, and you end up with a number more stable than any single test. The change from a position or equipment adjustment also shows up directly on the trend chart.
Will my history disappear when my subscription ends?
No. Records and original files are kept, and full access comes back when you renew. You can also delete your own data record by record at any time.
Your power file holds a wind-tunnel-grade answer
Upload a race file and try it. A few minutes later you will know your CdA.
Start estimating my CdA