Previous-Day High (PDH) and Previous-Day Low (PDL) show the highest and lowest prices from the last completed trading session. Marking them before the market opens gives you two clear reference levels for the day.
These levels do not tell you whether to buy or sell. They help you see where today's price is trading compared with the previous session.
What PDH and PDL mean
PDH is the highest price reached during the previous completed trading session. PDL is the lowest price from that session.
On a candlestick chart:
- PDH comes from the top of the highest wick.
- PDL comes from the bottom of the lowest wick.
- Both levels can extend into today's chart as horizontal lines.
If the market was closed yesterday, use the most recent completed trading session. Do not use an unfinished candle from the current day.
Why the wrong level can stay on your chart
The calculation is simple, but the daily routine can still cause errors. A trader may:
- leave Friday's levels on the chart after Monday closes;
- mark levels from the wrong symbol;
- use today's developing high or low by mistake;
- draw the line from the candle body instead of the wick; or
- keep an old line after changing the chart date or instrument.
An incorrect line can look valid during a fast market. Check the source before using the level in your plan.
How to mark PDH and PDL manually
Use this process before the next session starts:
- Open the correct symbol.
- Switch to the daily chart.
- Find the most recent completed trading candle.
- Mark the top of its highest wick as PDH.
- Mark the bottom of its lowest wick as PDL.
- Extend both lines into the next session.
- Return to your normal intraday timeframe.
Give the lines clear names. PDH and PDL are easier to check than two unnamed horizontal lines.
Check the session before using the levels
The previous day means the previous completed exchange session, not always the previous calendar date. Weekends and market holidays create gaps between session dates.
Also confirm:
- the exchange and symbol are correct;
- the chart uses the data source you normally trade from;
- the previous session has fully closed; and
- the lines belong to the current trading day.
If two chart providers show different values, check their session and price data before relying on either line.
PDH and PDL are chart references
Price can stop near a previous-day level, move through it or cross it several times. The line does not predict what happens next.
Your trading plan should still define:
- the setup you are waiting for;
- the condition that confirms an entry;
- the price that makes the setup invalid;
- the maximum position size; and
- the planned stop-loss and target.
PDH and PDL provide context. They do not replace a setup or risk rule.
How Zensibly keeps the levels ready
Zen Terminal can place the previous-day high and low on the chart automatically. The high uses the highest wick from the previous session. The low uses the lowest wick. Both extend into the current session.
This reduces repeated chart preparation. You still decide whether either level matters to your setup. Zensibly does not predict a breakout, reversal or profitable trade.
You can also add a named voice alert if you want to hear when price crosses a level. The alert tells you that the crossing happened. It does not tell you to enter a trade.
To see where the two lines come from, view previous-day high and low on the sample chart.
Quick pre-market check
Before using PDH and PDL, confirm:
- Correct symbol
- Most recent completed session
- PDH taken from the highest wick
- PDL taken from the lowest wick
- Old levels removed or updated
- Entry, stop-loss and target planned separately
- Alert name and direction checked, if used