CDA Calculator

CdA Calculator ยท GPX Analysis

CdA Calc

Second-by-second analysis ยท GPX

P = P_aero + P_roll + P_grav
1 ยท Upload GPX File
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Drop your GPX file here or click to browse

Must include power data (exported from Garmin, Wahoo, etc.)

.GPX
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Median CdA
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Mean CdA
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Std Dev
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Data Points
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Segment
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Position Rating
0.18 TT0.25 Aero0.32 Road0.40 Upright
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Avg Power
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Avg Speed
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Elev Gain
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Avg vAir
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Avg CdA per km โ€” 2ฯƒ โ†’ median โ†’ 2ฯƒ pipeline
CdA distribution across segment (median shown)
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Avg power split (CdA points only)
P_aero
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P_roll
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P_grav (net)
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May differ from course net elev due to point filtering
P_grav (climbs)
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Drivetrain Loss
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Why second-by-second? On rolling terrain, average-based calculators break down because you spend more time going slowly uphill than fast downhill. This tool solves for CdA at every data point โ€” hills and all โ€” then takes the median to ignore outliers from corners and surges. Wind is fetched automatically on upload and the scaling factor is auto-optimised after each calculation. For best results use a segment with consistent effort and minimal elevation change.
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