# Double-bottom Base Double-bottom Base is an indicator on [Vela](https://vela.luxalgo.com/chart), our next-generation charting platform, written in Pine Script®. Traces the W-shaped growth-stock base from confirmed swings: two sell-offs where the second low undercuts the first, depth, mid-peak and prior-uptrend checks, and a buy point set above the middle peak. Breakouts require expanded volume, a handle variant can tighten the entry, and a dashboard grades base proportions plus the volume character of the lows and right side. - Indicator in the LuxAlgo Library, by LuxAlgo, published Mar 29, 2026. - Access: free. - Concepts: [Double-bottom Base](https://www.luxalgo.com/library/concept/double-bottom-base/) (primary) - Open on Vela: https://vela.luxalgo.com/chart?pineScriptCodeId=kwj4128j95did2dmyn777k8f - Page: https://www.luxalgo.com/library/indicator/double-bottom-base/ **Double-bottom Base** detects the W-shaped [double-bottom base](https://www.luxalgo.com/library/concept/double-bottom-base/) by explicit rules: two sell-offs whose second low undercuts the first without collapsing, a middle peak high in the range after a qualifying advance, and a buy point just above that peak. The Library's first build draws the W, shakeout zone and buy level while the base pends; a dashboard grades proportions and volume character. ## How to Trade the Double-bottom Base? - **Reclaim**: a close back above the first low is the earliest sign the shakeout is working. - **Handle set**: a right-side swing high in the upper half moves the buy level to the handle high plus the pivot margin. - **Breakout**: a qualifying-volume close above the buy point confirms the base and starts buy-zone and stop tracking; without volume only a caution fires. - **Invalidation / stop**: a broken undercut low, a third test of the lows, a stale base or a stop hit end it. ## Double-bottom Base Settings - **Swing Detection Length** (default 5): pivot span tracing the W. - **Base Length (bars)** (defaults 35 to 250) and **Base Depth (%)** (defaults 10 to 40): allowed age and correction depth. - **Minimum Mid-Peak Position (%)** (default 50) and **Maximum Undercut (%)** (default 8): mid-peak floor and undercut cap. - **Prior Uptrend Filter** (default enabled), **Uptrend Window (bars)** (default 100), **Minimum Prior Advance (%)** (default 25), **Left High Tolerance (%)** (default 2): the prior-advance test. - **Pivot Margin (%)** (default 0.1): the margin forming the buy point. - **Breakout Volume Confirmation** (default enabled), **Volume Average Length** (default 50), **Breakout Volume Multiplier** (default 1.4): the volume test. - **Detect Handle Variant** (default enabled), **Buy Zone (%)** (default 5), **Fixed Stop After Breakout** (default enabled, 7%), **Post-Breakout Watch (bars)** (default 125): post-detection trade management. - **Dashboard and style toggles**: summary panel, W structure, shakeout zone, buy levels and invalidated-base history. ## Frequently Asked Questions ### How does this differ from the cup-with-handle base? The [cup-with-handle base](https://www.luxalgo.com/library/indicator/cup-with-handle-base/) carves one rounded low and buys near the rim. The W makes two distinct lows, the second undercutting the first, and buys the middle peak. ### Why must the second low dip under the first? The undercut flushes the stops parked at the prior low, removing supply before the right side begins. A second low holding above the first is not flagged, and one collapsing beyond the cap is a decline. ### What happens when price clears the pivot without volume? It fires a caution alert and stays pending. If price then extends above the left-side high without a qualifying breakout, the base is invalidated. ## Related indicators - [Ascending Base](https://www.luxalgo.com/library/indicator/ascending-base/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/ascending-base.md - [O'Neil Base Analysis](https://www.luxalgo.com/library/indicator/oneil-base-analysis/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/oneil-base-analysis.md - [Flat Base](https://www.luxalgo.com/library/indicator/flat-base/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/flat-base.md - [IPO Base](https://www.luxalgo.com/library/indicator/ipo-base/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/ipo-base.md - [Gap Fill Breakouts](https://www.luxalgo.com/library/indicator/gap-fill-breakouts/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/gap-fill-breakouts.md - [On-neck / In-neck / Thrusting](https://www.luxalgo.com/library/indicator/on-neck-in-neck-thrusting/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/on-neck-in-neck-thrusting.md - [Rising/falling Three Methods](https://www.luxalgo.com/library/indicator/rising-falling-three-methods/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/rising-falling-three-methods.md - [Swing Highs/Lows & Candle Patterns](https://www.luxalgo.com/library/indicator/swing-highs-lows-candle-patterns/) (Chart & Candlestick Patterns): markdown at https://www.luxalgo.com/library/indicator/swing-highs-lows-candle-patterns.md --- Source: https://www.luxalgo.com/library/indicator/double-bottom-base/ (LuxAlgo Library). Free to use with attribution: https://www.luxalgo.com/library/license/