What qualifies
- Two lows: swing lows (the lowest low of 4 days on each side) 10 to 100 days apart within the last 150 days, within 2% of each other (or 0.6× the 14-day ATR for very volatile markets).
- The second low is in the last 45 days, and no daily close since has fallen clearly below the lows.
- Neckline: the highest high between the two lows. It must be at least 8% (or 3× ATR) above the lower low.
- Context: price came down into the first low from above the neckline (within the 40 days before it), and nothing in the 20 days before the first low went lower.
- Breakout: a close above the neckline. Double top: the mirror image, with swing highs, a neckline at the lowest low between them, and a breakdown below it.
How traders use double bottoms
A double bottom shows sellers failing twice at the same level. The pattern is complete when price closes above the neckline; a common target is the neckline plus the pattern’s height. Until then it’s only a possible bottom, and a close below the lows cancels it. A double top is the bearish mirror image.
Patterns are found mechanically on daily candles from the data provider. Not investment advice.
Frequently asked questions
What does the quality score mean?
It’s a 0–100 score of how cleanly the pattern fits the rules above (for example, how tight the flag is, how round the cup is, or how closely the two lows match). It isn’t a probability and says nothing about what price does next. Use it to sort the list, then look at the chart: click a symbol to open it on FreeCharting.
Are these patterns reliable?
Chart patterns are a way to describe price action, not a prediction. Many fail, and they work differently in different markets. The detection is mechanical: a pattern can qualify on the numbers and still look wrong to your eye, and a pattern you’d draw by hand may miss one rule. Nothing here is investment advice.
Which markets can it scan?
Four, picked with the Market buttons above the table. Crypto (the default) scans the 250 busiest USDT pairs on Binance. Crypto perps scans the 200 busiest USDT perpetual futures on OKX. Both are free public data and need no key. US stocks scans about 600 US stocks and ETFs with your own free Alpaca key, and CME futures scans about 25 front-month CME Group contracts (stock indexes, Treasuries, oil, gas, metals, grains, livestock, currencies and CME bitcoin) with your own free Massive key.
Why do stocks and futures need a key?
Stock and futures prices are licensed data, so a website can’t hand them out for free. Alpaca (for stocks) and Massive (for futures) give anyone a free data key. Your key is saved only in your browser and sent only to that provider. See how to get a free Alpaca key and how to get a free Massive key for futures.
Is the data real-time?
Crypto and crypto perps are live from Binance and OKX, on daily candles that start at 00:00 UTC (today’s candle is still forming). Alpaca’s free stock data is 15 minutes behind the market, and Massive’s free futures plan is 8 hours delayed. Turn on auto-refresh next to the results to update the table in place every 30 seconds, minute or 5 minutes.