Force Index: Elder's Volume-Price Conviction Indicator for Futures Traders

Overview #

The Force Index has exactly one job: it tells you whether volume is supporting a price move or undermining it. That sounds simple, but it solves a problem that every futures trader faces daily — price can lie, but volume is harder to fake. When ES rallies 8 points on shrinking volume, that move is fragile. When it rallies 8 points with expanding volume, institutions are behind it. Force Index quantifies that relationship in a single number.

Alexander Elder introduced Force Index in Trading for a Living (1993). The formula is three variables: close-to-close price change, multiplied by volume. The result tells you whether bulls or bears are winning and how much conviction stands behind the move.

Force Index confirms trend entries, identifies exhaustion via divergence, and filters false breakouts. It underperforms in low-volume sessions and during news spikes. This article covers calculation, the two key parameters, signals, and ES/NQ day trading application.

The Formula: Price × Volume = Force #

Force Index = (Close_today − Close_yesterday) × Volume_today

That's it. Three components:

• Direction: Close_today − Close_yesterday is positive when price advanced, negative when it declined. A close of zero means price is exactly where it started -- no movement.
• Magnitude: The size of the price change. A 10-point ES move contributes 5× more to Force Index than a 2-point move.
• Conviction: Volume. A 10-point move on 800,000 ES contracts generates 5× the force of the same move on 160,000 contracts. Volume is the multiplier that turns price movement into a conviction signal.

The raw Force Index is volatile — a single high-volume bar creates a spike that makes the chart hard to read. Elder's solution: apply an Exponential Moving Average to smooth it. The two most useful smoothing periods are 2 and 13.

That's a useful counterpoint from a serious algo developer — the raw Force Index adds little beyond what volume already shows. Its value emerges specifically in the EMA-smoothed form and in divergence patterns.

Two-Period EMA: The Entry Timer #

Applying a 2-period EMA to raw Force Index creates an extremely sensitive, fast-moving line that Elder designed for one specific purpose: identifying when to pull the trigger on an entry within an established trend. It is not a trend-identification tool. It is not a divergence tool. It is an entry timer.

The trading rule Elder established for the 2-period Force Index:

• Long entries in an uptrend: Enter when the 2-period Force Index dips below zero (a minor pullback in an uptrend, indicating that sellers briefly had the upper hand even though the trend is up). This brief bearish Force Index reading is the optimal buy point -- the trend is intact but the immediate selling pressure is spent.
• Short entries in a downtrend: Enter when the 2-period Force Index rallies above zero (a temporary bullish spike during a downtrend). The trend is down, buyers stepped in momentarily, and that's your sell point.

The 2-period Force Index works best on daily charts for swing trading and 30-minute charts for day trading. On 5-minute charts it generates too many short-duration signals to be a useful trigger.

From his complete system documented in the Perrys Trading Platform thread (36 thanks): "Confirm that ForceIndex = BLUE [for longs]. Enter the trade 1 tick/pip above the Setup bar." Blue = EMA above zero (bullish), red = below (bearish). The entry requires both EMA trend and Force Index alignment simultaneously.

Thirteen-Period EMA: The Trend Filter #

While the 2-period Force Index is for timing, the 13-period EMA of Force Index is for trend identification. Its behavior is distinctly different: it moves slowly, confirms persistent trends, and filters out the noise that trips up the 2-period version.

The 13-period Force Index zero line is your regime indicator for the intermediate trend:

• Above zero: Bulls have maintained sustained volume advantage. The intermediate trend is up. Taking long trades is swimming with the current.
• Below zero: Bears have maintained sustained volume advantage. The intermediate trend is down. Short setups have the structural advantage.
• Zero-line crossovers: Not entry signals per se, but confirmation that a regime change is underway. A crossover from below to above on the 13-period Force Index is a meaningful structural shift -- not a spike, but a sustained momentum change backed by volume.

From @perryg's documented system (40 thanks): "ForceIndex = BLUE [for longs]. ADX = GREEN." Both had to align — momentum (Force Index positive) and trend strength (ADX rising). Neither condition alone was sufficient.

Zero Line: Bulls vs Bears in Real Time #

The zero line is the single most important reference level in Force Index analysis. When the indicator is above zero, buyers paid more for shares (or futures contracts) than they sold them for, on a volume-weighted basis. When it's below zero, sellers extracted more than buyers offered. It's a direct measure of which side is winning the auction, expressed as the product of price movement and volume participation.

In practical futures trading, the three zero-line behaviors that matter:

• Sustained above-zero in trending sessions: The 13-period Force Index holding above zero for extended RTH periods confirms the trend has volume support throughout -- not a signal to fade, but confirmation to hold longs.
• Repeated zero-line tags without crossing: Force Index approaching zero from above repeatedly but not penetrating is bullish -- sellers can't flip the regime. Use these tests as re-entry points in the trend direction.
• Zero-line breakdown on high volume: The most dangerous signal. Force Index above zero for an extended period, then a high-volume day pushes it through to the downside. This is the volume signature of genuine trend change, not the same as a temporary 2-period dip.

Divergence: Where Force Index Earns Its Edge #

@Fat Tails, one of NexusFi's most analytically rigorous contributors, went to the trouble of implementing Force Index in NinjaTrader, tested it, and ultimately reverted to raw volume. His conclusion on divergences:

Coming from someone who has coded and tested dozens of indicators, that's a meaningful endorsement. Force Index divergence works because it captures volume exhaustion before price exhaustion is visible.

Bearish Divergence (most actionable in futures)

Price makes a new swing high. The 13-period Force Index simultaneously makes a lower high than it made at the prior swing high. This pattern says: price advanced, but the volume behind it was less convincing than the prior advance. The bulls extended price higher but with less institutional participation. The move is on borrowed time.

Fat Tails documented this specifically for the March 2009 market bottom: "If you look at the market bottom in March 2009, the Force Index produced a nice divergence, as the final bottom did not attract as much volume as the prior downward peak in November 2008. The divergence is also facilitated by a wedge-shaped bottom." The bullish version of this pattern — price makes a lower low while Force Index makes a higher low — identified the exact reversal point that ended the financial crisis bear market. Volume was less heavy at the final low, meaning sellers were running out of conviction even as price printed new lows.

Bullish Divergence

Price makes a new swing low. The 13-period Force Index makes a higher low (less negative than its prior reading at the previous swing low). Selling pressure is diminishing. Fewer sellers are participating at the new low, even though price extended lower. Result: the selling phase is approaching exhaustion.

Entry: Wait for Force Index to cross back above zero after the divergence forms, combined with a price reversal structure — reversal bar or break above the local high between the two lows.

Hidden Divergence (Continuation)

Hidden divergence signals trend continuation. Hidden bullish: price makes a higher low during an uptrend pullback, but Force Index makes a lower low — sellers were temporarily active but price held structure, trend continues higher. Hidden bearish: price makes a lower high during a downtrend bounce, but Force Index makes a higher high during the bounce — buyers couldn't extend price despite showing more volume conviction. The highest-probability divergence entries combine three factors: confirmed Force Index divergence at two swing points, Force Index crossing zero in the divergence direction, and price structure reversal at a meaningful volume profile level (VAH, VAL, POC). Three conditions converging is where divergence becomes a genuinely high-probability setup.

Elder's Triple Screen System: Force Index in Context #

Force Index doesn't exist in isolation. Elder designed it as one component of his Triple Screen Trading System — a multi-timeframe framework where each screen serves a different analytical purpose.

The Triple Screen framework:

• First Screen (Weekly/Macro): Weekly MACD histogram direction. Rising = bull regime, longs only. Falling = bear regime, shorts only.
• Second Screen (Daily/Intermediate): Daily oscillator pullback within the weekly trend. In a bull regime, look for daily oscillator dips into oversold territory -- this is the buying zone.
• Third Screen (Entry): Force Index 2-period on an intraday chart. In a weekly uptrend with a daily pullback, wait for 2-period Force Index to go briefly negative, then place a buy stop above the prior day's high. Entry triggers on the next uptick with Force Index confirming.

Elder Impulse System: Force Index's Companion #

The Elder Impulse System pairs naturally with Force Index. It colors each price bar green when both the 13-EMA slope and MACD histogram point the same direction (bullish), red when both point down (bearish), or blue when they disagree.

The combination: Impulse System defines the regime (green = longs only, red = shorts only, blue = either). Force Index then times the entry within that regime. When the Impulse System transitions from red to blue and Force Index simultaneously crosses above zero, both trend direction and volume conviction align — the setup Elder designed the two tools to identify together.

Day Trading ES and NQ #

Force Index behavior differs meaningfully across contracts. Futures markets have specific volume patterns, volatility characteristics, and session dynamics that require contract-specific calibration.

ES (S&P 500 E-mini) — Standard 13-Period EMA

ES trend days (ADX above 30) show the cleanest Force Index behavior: the 13-period EMA stays firmly on one side of zero for the majority of the session. Range days (ADX below 20) create erratic zero-line oscillations that generate false signals. Identify the day type first; then decide whether to use Force Index as a trend-following or mean-reversion tool.

NQ (Nasdaq 100 E-mini)

NQ moves 1.8-2.2x ES in point terms. Tech events (earnings, AI news, Fed) create NQ Force Index spikes that don't appear on ES simultaneously — that divergence signals tech leadership. Some NQ traders use 8 or 10 periods instead of 13 to capture NQ's faster momentum without excess noise.

Force Index vs Other Volume Indicators #

Force Index competes with several other volume indicators for attention. Understanding the structural differences helps you choose the right tool for the right situation.

Platform Implementation #

NinjaTrader 8

Force Index (EFI) is available as a native indicator in NinjaTrader's standard indicator library. Parameters: EFI Period (default 13 for the EMA smoothing). The indicator plots the smoothed Force Index as a histogram or line in a sub-panel.

Perry's NinjaTrader implementation uses EMA-13 with color coding: "ForceIndex_v02 (EMA 13) — First row of coloured bars at bottom of chart." Blue bars when above zero, red bars when below. For the complete Elder setup, add a second Force Index instance with Period=2 — 13-period for trend identification, 2-period for entry timing, both visible on the same sub-panel.

TradingView (Pine Script)

Force Index is built-in on TradingView. Custom implementation: (close - close[1]) * volume gives raw Force Index; ta.ema(fi, 13) for the trend version, ta.ema(fi, 2) for entry timing. Color the histogram green above zero, red below.

Sierra Chart

Available as "Force Index" under Studies. Select EMA smoothing for the standard Elder implementation.

Common Mistakes #

1. Treating every zero-line cross as a trade entry. Zero-line crossovers on the 13-period Force Index confirm trend regime changes. They are not mechanical entry signals. In a trending session, you'll see multiple consolidation periods where Force Index oscillates around zero without producing meaningful directional moves. Crossovers need context: is ADX rising? Is the price structure confirming? Without additional confirmation, zero-line crossovers have roughly a 45% success rate as standalone entries — basically a coin flip.

2. Ignoring ADX as a filter. Force Index works well in trending markets. In ranging conditions (ADX below 20-25), the volume and price-change components oscillate without directional conviction, generating noise rather than signals. Adding ADX ≥ 25 as a mandatory condition reduces false entries much. Without this filter, especially on slow-volume days (summer markets, holiday sessions), Force Index generates frequent zero-line crossovers that lead nowhere.

3. Using Force Index in isolation. Elder designed it as one component of a multi-timeframe system. A 5-minute zero-line cross can be bullish while the daily Force Index is firmly negative — that's a counter-trend move, not a trend entry. Single-timeframe Force Index alone has roughly 45% win rate; multi-timeframe context is what creates edge.

4. Comparing raw Force Index readings across contracts. +50,000 on ES is not the same as +50,000 on NQ — volume characteristics differ by 2-3x. Always read Force Index relative to its own recent history, not in absolute terms. For divergence, use only the 13-period EMA — the raw series is too spiky and the 2-period too short to show reliable swing structure.

Risk Management Integration #

Force Index signals entry direction and timing. Stops and position size belong to price structure:

• 2-period dip entries: Stop below most recent swing low, 1-2 ATR below the entry bar's low.
• 13-period cross entries: Stop below structural support confirmed by the regime change (prior session's low for swing, prior day's low for daily).
• Divergence entries: Stop beyond the pattern extreme -- below second low (bullish), above second high (bearish).
• Exit: Force Index lower high while price advances = incipient divergence. Exit before the full pattern completes.

Summary #

The Force Index solves one specific problem: it tells you whether volume is confirming or undermining price moves, in a single number that's easy to interpret and available on every platform. Elder designed it as a directional tool (not just a volume indicator), combining price change with volume to produce a measure of buying or selling conviction.

The practical rules:

• 13-period EMA: regime identification (above zero = bull, below zero = bear)
• 2-period EMA: entry timing within established trends (buy when negative in uptrend, sell when positive in downtrend)
• Divergence is the highest-probability signal -- most reliable for spotting exhaustion before price confirms it
• ADX ≥ 25 is a mandatory filter for trend-following entries; without it, Force Index crossovers in ranging markets are noise
• Use within Elder's Triple Screen framework for multi-timeframe context; Force Index as a standalone indicator is weaker
• The Elder Impulse System (EMA slope + MACD histogram bar coloring) pairs naturally with Force Index -- Impulse provides regime identification, Force Index provides entry precision

For ES day traders: 13-period Force Index for session bias, 2-period for entry timing, ADX ≥ 25 as the mandatory filter, daily chart for context. The divergence patterns are worth watching regardless — catching volume exhaustion at key structural levels is one of the most reliable edge sources in futures markets.