Follow the Brown calculation in four stages
Brown's original MTA Journal article describes two exponential smoothing stages followed by a simple moving average, with the second EMA minus that average plotted as a histogram. TC2000's official implementation documents the same 14/5/3/9 defaults. Here, every period counts chart bars and the final nine-bar average includes the current observation.
- For ordinary nonzero average gains and losses, RSI = 100 − 100 / (1 + average gain / average loss). Wilder smoothing uses alpha = 1/14; this is different from the EMA alpha of 2/(length + 1).
- For an established EMA, new value = alpha × current input + (1 − alpha) × previous EMA. Replacing the final SMA with an EMA changes the indicator.
- A separate arithmetic check: Wilder average gain 1.5 and average loss 1 produce RSI = 60. These are assumed averages, not the last single-bar gain and loss.
| Stage | Calculation | Default |
|---|---|---|
| R: relative strength | Wilder RSI of close | 14 bars |
| A: first smoothing | EMA(R) | 5 bars; alpha = 1/3 |
| B: second smoothing | EMA(A) | 3 bars; alpha = 1/2 |
| S: signal baseline | SMA(B) | 9 bars; equal weights |
| D: histogram | B − S | RSI-point difference |