Stochastic Momentum Index (SMI) is a refined stochastic oscillator designed to measure momentum more smoothly than a classic Stochastic. This cTrader implementation matches the commonly used TradingView formulation by applying double EMA smoothing to both the relative range and the high–low range, producing a clean, stable momentum curve that works well across trending and ranging conditions.

What it shows

• The SMI measures where the close sits relative to the midpoint of the recent high–low range, normalized and scaled.
• Values tend to oscillate between -100 and +100.
• Overbought/oversold reference levels (default +40 / -40) help identify stretched conditions and momentum extremes.

Plots

• SMI: the main momentum line.
• SMI-based EMA: a signal line (EMA of SMI) for crossovers and confirmation.
• Overbought / Oversold / Middle (0) levels for quick visual context.

How traders use it

• Trend regimes: Use the 0-line as a directional filter (above 0 = bullish pressure, below 0 = bearish pressure) and trade pullbacks via SMI vs signal-line crossovers in the direction of the trend.
• Mean-reversion regimes: Fade extremes when SMI returns from overbought/oversold and confirms with a crossover, often targeting the 0-line as the first mean-reversion objective.
• Divergences: Momentum divergence between price and SMI can highlight potential weakening swings.

Multi-timeframe option

• Select a Source Timeframe to calculate SMI from a higher timeframe while displaying it on the current chart (ideal for filtering noise and improving signal quality).
• Or enable Use Chart Timeframe to keep calculations on the current timeframe.

Inputs

• %K Length: lookback window for highest high / lowest low.
• %D Length: smoothing length used in the double-EMA calculation.
• EMA Length: signal line length (EMA of SMI).
• Overbought / Oversold: reference levels.
• Use Chart Timeframe / Source Timeframe: optional higher-timeframe calculation.

This indicator is built to be lightweight, stable, and practical for real trading workflows—whether you trade trend continuation, ranges, or use SMI as a confirmation filter within a broader strategy.