How to calculate ADX
+DM = High − Previous high (if larger than the down-move and > 0)
−DM = Previous low − Low (if larger than the up-move and > 0)
+DI = 100 × Smoothed +DM ÷ Smoothed TR −DI likewise
DX = 100 × |+DI − −DI| ÷ (+DI + −DI)
ADX = Wilder average of DX over n bars
Paste prices oldest-first, one value or row per bar — straight from a spreadsheet or CSV export. Use “Sample data” to try it instantly.
Worked example
- +DI = 30 and −DI = 10.
- DX = 100 × 20 ÷ 40 = 50.
- Averaged over 14 bars, an ADX in the 30s–40s indicates a strong uptrend (+DI above −DI).
How to interpret ADX
- ADX below 20: weak or no trend — range strategies tend to work better.
- 20–25: a trend may be forming.
- Above 25: trending; above 40: very strong trend.
- Direction comes from +DI vs −DI, not from ADX itself.
Limitations and common mistakes
- ADX needs about 2 × n bars of data before the first value appears.
- A falling ADX from high levels means the trend is weakening, even if price still rises.