How to Plot a Daily Indicator on an Intraday Chart in ThinkOrSwim (Free Code)

Overview

In this tutorial I show you how to use an aggregation period in thinkScript to plot a daily time frame indicator on an intraday ThinkOrSwim chart. The example is the 50-day simple moving average on a 5-minute chart of Coca-Cola (KO), so you can watch price react to a daily level without flipping between charts.

The whole change is one parameter added to the closing price. It's a short, beginner-friendly lesson for day traders who already mark daily levels and want them on the chart they trade from. The same idea is behind our multi-time frame indicators.

Key Takeaways

What Is an Aggregation Period in ThinkOrSwim?

An aggregation period in ThinkOrSwim is the time frame of the candles a study reads its price or volume from. That covers the open, high, low and close of each bar. By default, a study uses the chart's own aggregation period, so a 50-period SMA on a 5-minute chart averages the last 50 five-minute closes.

thinkScript lets you override that for any price value. You name the period you want, and the study reads that time frame's candles no matter what chart it sits on. These are some of the most commonly used periods, with the constant you type for each:

The full list is in ThinkOrSwim's thinkScript reference: search for AggregationPeriod, which is what I show on screen in the video. Capital letters don't matter here. Our own downloads mix styles, such as AggregationPeriod.Day and AggregationPeriod.FIFTEEN_MIN, and they compile.

Why Plot a Daily Level on an Intraday Chart?

A daily level on an intraday chart shows you where a reaction might start while you watch the bars you trade. Coca-Cola's daily chart in the video had stacked moving averages: the 8, 21 and 34-period EMAs on top, the 50-period SMA as a yellow dashed line and the 200-period SMA as a white dashed line.

On February 14, KO tested the 50-day SMA. The daily candle only wicked into it, and the wick lined up with the 50 SMA almost to the penny before price reacted. Hindsight makes that look obvious. The question I ask in the video is this: can you see a moment like that setting up intraday and trade the reaction?

For that, the daily level has to be on the 5-minute chart. Otherwise you're flipping back and forth between a daily chart and a 5-minute chart, and the 5-minute chart's own 50 SMA is a different line altogether.

How to Write the Daily 50 SMA Study

The daily 50 SMA study is one line of thinkScript. Build it on a daily chart first, so you can compare it with the built-in 50 SMA:

1. Open a daily chart, click the Studies icon, then Create.
2. Name the study. Mine was a sample called TI Intraday SMA 50 Example.
3. Type the normal 50 SMA line, then add the period parameter to close (both versions are below).
4. Click OK, then Apply, and check that a cyan line now sits on top of the chart's 50 SMA.
5. Switch the chart to 5 minutes. The cyan line keeps showing the daily 50 SMA.

Step 1: The Normal 50 SMA

This is the standard way to define a simple moving average in thinkScript:

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SimpleMovingAvg is ThinkOrSwim's simple moving average function. It takes the price to average and the length: here the close and 50 bars. On a 5-minute chart, that means 50 five-minute closes, about 250 minutes of trading. That's not the level we want.

Step 2: Point the Close at the Daily Chart

The close can take a parameter of its own, and that parameter is the aggregation period:

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close(period = AggregationPeriod.DAY) tells ThinkOrSwim to use daily closes no matter what chart the study is on. The length stays at 50, so the line is now the 50-day SMA. Click OK and the code compiles. To use a weekly 50 SMA instead, change DAY to WEEK.

Checking the Line on the Daily and 5-Minute Charts

The daily 50 SMA study plots a cyan line, since cyan is the default color for a new plot. On the daily chart, that line lands right on top of the yellow dashed 50 SMA, which tells you the code works. On the 5-minute chart, it shows the daily 50 SMA's value for each day. The table shows what each version plots:

What Happened on KO's 5-Minute Chart

KO's 5-minute chart on February 14 is the example in the video. The cyan line was the daily 50 SMA, and the 50 SMA breach came at about 8:10 a.m. Pacific. Price bounced into the line, a small base formed, our Edge Signals indicator printed oversold signals, and then price bounced up from there.

It doesn't always look this clean. My point in the video is that levels like this tend to see reactions when price reaches them. Those reactions could come from algos or institutions. Seeing the level on the intraday chart lets you watch for that reaction as it happens.

Example 2: A Daily ATR in a Label

The Average True Range is a study you can't fix with one parameter. This example isn't in the video: it's from my written version of this lesson.

ATR doesn't take a price input, because it reads the high, close and low inside its formula. Here's ThinkOrSwim's ATR source code:

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To read daily candles, each of the 3 prices inside TrueRange gets the daily period. Then an AddLabel line prints the value:

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Now the label shows the 14-period ATR from daily candles on any intraday chart. If labels are new to you, our AddLabel tutorial covers the 3 parameters. For ATR on its own, see our Average True Range scans.

Which Studies Work With an Aggregation Period?

Any study that takes a closing price or volume as a parameter can read another time frame. You point that price at the period you want. I use the simple moving average in the video, but the same change works for an exponential moving average or a weekly line. These 2 lines are my own examples of each:

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In the video I mention our Market Pulse indicator as another study you could plot from the daily chart. Our free Reversion to 50 Day SMA indicator uses this exact call with a symbol added: close(symbol = "SPY", period = AggregationPeriod.Day).

Some built-in studies have no price input at all. The built-in DMI is one, so our MTF DMI indicator rebuilds DI+, DI- and ADX from each time frame's highs and lows, the same way the ATR example above rebuilds True Range.

Limits and Common Errors

ThinkOrSwim can read time frames equal to or larger than the chart's own, never smaller. In our Multiple Time Frame Moving Averages tutorial, a 15-minute EMA on a 30-minute chart made every line disappear, with the error "the secondary period cannot be less than the primary". That indicator uses if/else blocks on GetAggregationPeriod() to plot only the lines a chart can show.

• The line disappears on a weekly chart. A daily study on a weekly chart asks for a smaller time frame than the chart's. Use it on daily and intraday charts.
• The line still changes when you switch charts. The period parameter is missing or in the wrong place. It goes inside the parentheses right after close: close(period = AggregationPeriod.DAY).
• The ATR label doesn't match the daily ATR. All 3 prices need the period. Leave one out and the formula mixes daily and intraday candles.
• The code won't run in a scan. Scans are stricter. In our Smarter MACD tutorial, the higher time frame code gave the scan error "secondary period is not allowed". The workaround there drops the period parameter and lets the scan's own aggregation setting pick the time frame.

How I Use Daily Levels Intraday

The daily 50 SMA on a 5-minute chart is a level to watch, not an entry by itself. I look for price moving into the level, then use an overbought or oversold indicator to confirm the move into it and the move away from it. Our list of 5 oversold indicators for ThinkOrSwim has options for that step.

When a setup forms at the level, decide where the stop goes before you enter, and size the position so a stop-out costs a small, fixed share of your account. A level that held once can break the next time.

Our multi-time frame indicators are built on the same aggregation period idea. The MTF Squeeze indicator checks 18 time frames for a squeeze from one chart, and members get the MTF Triple Squeeze and MTF Squeeze Histogram in the Squeeze Course. More lessons like this one are on the thinkScript tutorials page.

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