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Candlestick Outputs

TL;DR: 0 means no pattern. A positive value means a bullish pattern, a negative value a bearish one.

What the values mean

Every candlestick function (CDL*) returns one whole number per bar. Read the sign first: zero, positive or negative. The size adds detail:

ValueMeaning
0No pattern on this bar
+/-100The usual case: the pattern is on this bar
+/-80A weaker form of the pattern, for example CDLENGULFING
+/-200This bar confirms a pattern found a few bars earlier, for example CDLHIKKAKE

Most patterns only ever return 0 and +/-100.

Some patterns point only one way, so they return only one sign: a hammer is always 100, a shooting star always -100. A few have no direction: a doji is just 100 when found, and a spinning top's sign is only the candle's color. Each function's page lists its values under Output Values.

A value describes the candles, not a trade. A pattern does not check the trend before it, so whether it is a signal is up to you.

Reading them from code

You do not have to hard-code any of this. Through the Abstract API, each candlestick function carries flags that say which of these values it can return, so a charting app or a strategy builder can find out at run time.

How often patterns fire

Many patterns are rare: a few years of one symbol's daily bars may show none, and that is not a bug. The page of each rare pattern says so under Notes:

  • Bulkowski's frequency rank. Thomas Bulkowski ranks the 103 patterns he tested, over about 4.7 million candles, by how often each occurs, 1 being the most frequent. The note links his page for the pattern on thepatternsite.com. His definitions are his own, so TA-Lib can find a pattern more or less often than his rank suggests.
  • How often TA-Lib's function fires over about 16,000 daily bars of crypto, May 2021 to November 2026: eight trading pairs on Uniswap v3, Ethereum (WBTC/USDC, WETH/USDC, WETH/USDT, WBTC/WETH, LINK/WETH, UNI/WETH, AAVE/WETH, MKR/WETH), built from the pools' on-chain swaps. Crypto trades around the clock, so a day seldom opens away from the previous close, and a pattern that needs a gap between whole candles almost never fires there.

A pattern counts as rare when Bulkowski ranks either of its forms 78th to 103rd, or when its function fires fewer than 16 times in those bars (1 per 1,000).

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