How to calculate MAE and MFE for swing trades

What MAE and MFE measure

Maximum adverse excursion (MAE) is the largest unrealized move against the position between entry and exit. Maximum favorable excursion (MFE) is the largest unrealized move in the position's favor over the same period.

These are path measurements, not realized results. MFE does not mean a trader could have exited the entire position at the exact high. MAE does not automatically mean the original stop was too wide or too tight. Each number becomes useful only when it is compared with the trade plan and with a group of similar trades.

MAE and MFE formulas for a long trade

For a long position, use the lowest and highest tradable prices recorded while the position was open:

If the position never traded below entry, adverse excursion can be recorded as zero rather than as a negative value. If it never traded above entry, favorable excursion can likewise be recorded as zero.

MAE and MFE formulas for a short trade

The direction reverses for a short position because higher prices are adverse and lower prices are favorable:

Borrow costs, dividends owed, fees and forced buy-ins are separate from excursion. Track those costs when calculating actual trade results rather than hiding them inside the price-path metric.

Convert the excursion into dollars and percentages

Per-share values are easy to verify against a chart, but dollar and percentage values make trades with different prices and share counts easier to compare.

• Dollar MAE: MAE per share × shares held during that interval.
• Dollar MFE: MFE per share × shares held during that interval.
• MAE percentage: MAE per share ÷ entry price × 100.
• MFE percentage: MFE per share ÷ entry price × 100.

If size changed during the trade, do not multiply one price extreme by the maximum share count. Calculate the dollar excursion separately for each interval with a different position size, or use the per-share and R versions for consistent strategy analysis.

Normalize MAE and MFE in R

One R is the initial planned risk from entry to the original invalidation. Expressing excursion in R makes a $20 stock and a $200 stock comparable and connects the review to the risk accepted before entry.

Preserve the original risk denominator even if the stop later moves. Otherwise the same trade's historical R measurements will change during the review. Read how to set a trade invalidation level and how to size from stop distance before using R-based excursion.

Worked example: long swing trade

Assume a trader buys 200 shares at $50 with an original invalidation at $47.50. Initial risk is $2.50 per share, or $500 in total. While the position is open, the lowest traded price is $48.75, the highest is $56 and the eventual exit is $54.

• MAE per share: $50 − $48.75 = $1.25.
• MAE in R: $1.25 ÷ $2.50 = 0.5R.
• Dollar MAE: $1.25 × 200 = $250.
• MFE per share: $56 − $50 = $6.
• MFE in R: $6 ÷ $2.50 = 2.4R.
• Dollar MFE: $6 × 200 = $1,200.
• Realized result: ($54 − $50) × 200 = $800, or 1.6R before costs.

The trader captured 1.6R of a theoretical 2.4R favorable excursion. That fact alone does not prove the exit was early. The $56 print may have been brief, may have occurred before a planned holding-period condition was met, or may not have offered enough liquidity for the full exit.

Track realized return, achievable return and MFE separately

Three numbers answer three different questions:

1. Realized return: What did the actual fills produce after trading costs?
2. Achievable return: What exit was reasonably available under the written strategy, using observable confirmation and realistic liquidity?
3. Maximum favorable excursion: What was the most favorable chart price reached before the position closed?

MFE is an opportunity ceiling, not a fair performance target. Comparing every exit with the precise intraday high creates hindsight bias. Achievable return should use a repeatable exit rule—such as a daily close, a trailing structure break, a planned target zone or a volume-confirmed reversal—not a price selected after seeing the completed chart.

Use bar data consistently

Daily high and low data are usually sufficient for multi-day swing trades, but they do not reveal which extreme occurred first inside the session. Intraday bars provide a more precise path, especially when both the stop and target fall inside the same daily range.

• Use the same time resolution for every trade in the comparison set.
• Include extended-hours prices only if the strategy could actually trade then.
• Use adjusted historical data carefully around splits and distributions.
• Mark halts, opening auctions and illiquid prints that may distort an extreme.
• Record bid-ask spread and actual fills when a chart print was not realistically executable.

Investor.gov notes that online orders are not instantaneous and that market prices can change before execution. Its guide to online investing and order execution is a useful reminder that a displayed high or low is not automatically an available fill.

Separate price excursion from stop execution

A stop price is a trigger, not a guaranteed execution price. In a fast market or overnight gap, the actual exit may be worse than both the planned stop and the first visible regular-session price. Investor.gov's Understanding Order Types bulletin explains this distinction.

Record four fields separately: planned invalidation, stop trigger, actual exit fill and slippage. MAE should describe the observed adverse path while the position was open; slippage should describe the execution gap between the intended or triggered exit and the actual fill.

What MAE can reveal across many trades

Group trades by the same setup, market regime and holding period. Then examine the distribution rather than one dramatic example.

• If most eventual winners remain below 0.4R adverse excursion, entries that immediately reach 0.9R may deserve closer screening.
• If many valid winners first move beyond the current stop, the entry timing or invalidation method may need testing.
• If losing trades frequently show small MAE before reversing, exits or profit protection may matter more than stop width.
• If MAE expands when several positions share the same catalyst, review correlated portfolio heat.

These are research prompts, not automatic rule changes. A wider stop increases dollar risk unless position size falls, and no historical pattern guarantees the next trade will behave similarly.

What MFE can reveal across many trades

• Low MFE on losers: entries may lack confirmation or occur in weak market context.
• High MFE but small realized gain: the management rule may surrender too much open profit.
• High MFE after the planned exit: the original exit may still be correct if the later move required violating the strategy.
• Consistent MFE near one level: a partial-profit or trailing-stop rule may be worth testing.

Compare average, median and percentile ranges. One extreme winner can inflate the average, while the median describes the typical trade more reliably. Keep winners, losers, long trades and short trades separated before combining them into a broader strategy view.

A practical excursion journal

Add these fields to every completed trade:

• Setup name, direction and market regime
• Entry, original invalidation and initial risk per share
• Shares held during each sizing interval
• Lowest and highest tradable price while open
• MAE and MFE in dollars, percentage and R
• Actual exit, realized R and trading costs
• Achievable exit under the written rule
• Time to MAE, time to MFE and total holding time
• Gap, halt, liquidity or event-risk notes

Use the framework in reviewing a losing swing trade without hindsight bias to grade the decision and execution alongside these measurements.

Common MAE and MFE mistakes

• Using the chart after exit: excursion stops when the position closes.
• Comparing unlike trades: different setups and holding periods can have different path behavior.
• Ignoring changing size: one extreme multiplied by the wrong share count distorts dollar exposure.
• Treating MFE as guaranteed profit: a high or low print may not have been available for the full position.
• Optimizing rules to a small sample: hindsight can make a fragile rule look precise.
• Changing stops without resizing: a wider risk distance changes planned dollars at risk.

Bottom line

MAE measures the deepest move against a trade; MFE measures the best move in its favor. Calculate both per share, in dollars, as a percentage and in R, then compare them with actual and realistically achievable results. Their value comes from repeated, consistent measurement across similar trades—not from judging one exit against the perfect point on a finished chart.

Educational framework only—not individualized investment advice, a recommendation to trade, or a promise that MAE/MFE analysis will improve results. Historical excursions do not predict future price paths. Trading and investing involve risk, including loss of principal, gaps and execution away from expected prices.