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Order Blocks Indicator for ThinkOrSwim

Draws a box on the last opposite candle before a big move, keeps it on your chart, and removes it once a candle closes through it. Free, with the full code and a 31-minute video that builds it line by line.

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IndicatorFreeDaily charts31 min video67 lines of codeUpdated Nov 1, 2026
Order Blocks indicator on an SPY daily chart in ThinkOrSwim. Violet boxes are bull order blocks and yellow boxes are bear order blocks, with cyan fair value gaps from the free Fair Value Gap indicator, May 2025 to January 2026.
Bull order block Bear order block Fair value gap, from the FVG indicator SPY daily, May 2025 to Jan 2026, default settings
What it marks
The last opposite candle before a big candle that closes past it
Default filter
Big candle at least 1.0 × the 14-bar ATR, high to low
When a block clears
A candle closes through its far edge
Tested on
648 stocks and ETFs, about 2 years of daily bars
On this page

What is an order block?

An order block is the last candle against the move, right before a big candle that breaks away from it. Candle 1 is a down candle. Candle 2 is a big up candle that closes above candle 1's high. Candle 1 is your order block, and the box covers its full range, high to low.

The popular story is that big institutions left orders at that price and defend them when price comes back. I can't see their order books and neither can you, so we don't need that story. The behavior itself is something we can test.

The bearish version is the mirror image: an up candle, then a big down candle that closes below its low. In thinkScript, candle 2 is the current bar and candle 1 is 1 bar back, so the core check on each side is one comparison: close > high[1] for a bull block and close < low[1] for a bear block.

Bull order blockA down candle, then a big up candle that closes above its high.
Bear order blockAn up candle, then a big down candle that closes below its low.
ClearedA candle closes through the far edge, and the box comes off the chart.

What order blocks did next

Before writing the indicator, I measured every order block on 648 stocks and ETFs using daily bars. Move the filter to see how the size of the big candle changes what happens after it. The indicator's minMove input works the same way.

1.00
15,168bull blocks pass the filter
83.0%came back within 20 trading days
64.3%were still intact 5 days after a retest that closed in the near half

Still intact 5 days after the first retest

Split by where the retest closed inside the block.

Came back and broke, days after the block

came back   broke   dashed = minMove 0.5

A retest by itself isn't a buy signal. Five trading days after the first retest, bull blocks returned +0.55% on average, about the same as the +0.50% from any 5-day stretch in the same stocks. Use a block to decide where to look. Use something else to decide when to act.

How this was measured

Universe: 648 stocks and ETFs from our daily bar table, through Oct. 20, 2026. Most symbols start in July 2024, and about 15 index and sector ETFs go back to November 2015, so read this as mostly 2 years of a rising market. A bull block forms on bar i when bar i−1 is a down candle, bar i is an up candle that closes above bar i−1's high, and bar i's high to low range is at least minMove × ATR. The block runs from bar i−1's low to its high. Bear blocks mirror it. Came back: price trades back to the block within N days. Broke: a close through the far edge within N days. Near half and far half: where the first retest closed inside the block, among retests that closed on the right side of the far edge. Intact: no close through the far edge from the retest through 5 bars after it. ATR is the 14-bar simple average of true range, and each block is followed for 20 trading days.

How to read the blocks on a chart

Here's what I look for, using the Apple and SPY charts from the video.

AAPL daily chart, June to August 2025: price launches from a violet order block, comes back down to it on August 1, and takes off again.
A pullback into a violet block that holds

On June 30, 2025, Apple launched higher from one candle. A month later, on August 1, price walked back down into the box, closed above its bottom, and took off again.

SPY daily chart, September 2025: a cyan fair value gap sits on top of a violet order block, and price fills the gap but holds the block.
An order block with a gap on top of it

SPY left a violet block with a cyan fair value gap right above it. On September 2, 2025, price filled the gap, but the order block underneath held.

AAPL daily chart, December 2025 to January 2026: price trades back up into a yellow bear order block on January 2 and closes back below it.
A push into a yellow block that gets turned away

Apple's big down candle on December 15, 2025 left a yellow box overhead. On January 2, price traded back up into it and closed back below. By January 6, it had closed through the violet box underneath, which took that box off the chart.

The far edge of the box is your line in the sand. One daily close through it and the idea is done. Before that, watch where the retest closes. In the study, a close in the near half of the block was still good a week later about 6 times out of 10. A close in the far half broke about 2 times out of 3.

You'll see a lot of blocks on a chart. Raise minMove to thin them out, then pair the ones left with a confirmation trigger. I use Edge Signals for that, and the video ends with how I combine them.

How to install the indicator in ThinkOrSwim

  1. Download the indicator and open the .txt file, then copy all of the code. You can also copy it from the code block on this page.
  2. In ThinkOrSwim, click the Studies icon, then click Create.
  3. Delete the placeholder code and paste in the order block code.
  4. Name the study. I called mine TI_OrderBlocks.
  5. Click OK, then Apply. Start on a daily chart, which is what the study uses.

New to custom studies? The walkthrough on how to import a thinkScript study into ThinkOrSwim covers the same steps with screenshots.

The Edit Studies window in ThinkOrSwim, with the Create button under the list of studies.
Studies, then Edit studies. Create sits under the list of studies.

Inputs

InputDefaultWhat it controls
minMove1.0How big candle 2 has to be, high to low, as a multiple of ATR. Raise it to see only the biggest moves, lower it to see more blocks.
ATRLength14Number of bars in the ATR average that minMove is measured against.

How the code works

Step 1: Inputs and ATR

I need a way to measure what counts as a big push on any stock, so I use ATR as the yardstick. ThinkOrSwim has a built-in ATR function you could call instead. I wrote it out with Average and TrueRange so you can see what it calculates, and pulled the length out as an input.

This step’s code is free with an account. Create one or sign in.

The thinkScript editor with the minMove and ATRLength inputs and the ATR line.ATR Filter · 7:40

Step 2: Define the big candle

A candle counts as big when its range, high to low, is at least minMove times the ATR. With the default of 1.0, that's one full ATR on your current timeframe.

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While building this, I used AddChartBubble to check that each condition showed up where I expected it. That's a handy way to debug your own changes, and I took it out of the final code.

The thinkScript editor with the bigCandle line.Big Candle · 9:34

Step 3: Define bull and bear order blocks

A bull block has four conditions. The previous bar closed below its open, the current bar closed above its open, the current close is above the previous high, and the current bar is a big candle. The bear side flips each one.

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The thinkScript editor with the bullOrderBlock and bearOrderBlock definitions.Block Coding · 12:24

Step 4: Carry the box forward without arrays

ThinkOrSwim doesn't have arrays, so I declare bullTop and bullBottom first and set them inside an if/else block. On the bar where a bull block forms, the top and bottom come from the previous candle. On every bar after that, each variable takes its value from the previous bar, which carries the box forward.

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The middle branch clears the box. Once a candle closes below the bottom of a bull block, both values reset to Double.nan and the box comes off the chart. The bear side mirrors this with a close above the top.

The thinkScript editor with the if/else block that carries bullTop and bullBottom forward.Block Storage · 15:20

Step 5: Plot the boxes as clouds

If you plot bullTop directly, you get one continuous line that connects each block to the next. To fix that, the plot returns Double.nan on the bar where a block forms, so each new block starts fresh. AddCloud then shades the space between each top and bottom.

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The AddCloud lines in the editor with the order block boxes on the chart behind it.Cloud Plotting · 21:23

Full thinkScript code

TI_OrderBlocksthinkScript · 67 lines
The full code is free with an account

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Video: building the indicator, line by line

31 minutes, from what an order block is to the finished study in ThinkOrSwim. Each chapter opens the video at that point.

The thinkScript editor in ThinkOrSwim with the order block code half written. How to Build an Order Block Indicator in ThinkOrSwim · 31:33

    Limitations

    ThinkOrSwim only

    The code is thinkScript. There is no TradingView version.

    One block per side

    A new bull block replaces the previous bull block, so older open blocks drop off the chart. Same for bear blocks.

    Not an entry signal

    A block shows where price may come back to. It doesn't tell you when to act, and the study found no return edge from the retest alone.

    Tested on daily bars

    It plots on weekly and intraday charts, but the study only covers daily bars.

    One chart at a time

    To find every stock heading back into a block, you need a scan. That's Part 2, below.

    Part 2: the Order Block Scan

    Part 2 runs the same logic across a whole watchlist. It has three pieces:

    1. An upgrade to this indicator that adds a 50% line, so you can see which half of the block a retest closes in.
    2. A Stock Hacker scan that finds stocks retesting an open order block today.
    3. A custom scan-tab column that prints each stock's block levels, so you can rank the results.

    It ends with how I pair the scan with Edge Signals to time an entry.

    Part 2 is for members and it's on the way. It's included with Stock Volatility Box, Futures Volatility Box and the Bundle, along with the Squeeze Course and every other members-only tutorial.

    Questions

    How do I install the Order Blocks indicator in ThinkOrSwim?

    Copy the code from this page or the .txt download. In ThinkOrSwim, click Studies, then Create. Delete the placeholder code, paste in the order block code, name the study (I used TI_OrderBlocks), and click OK, then Apply.

    What do the violet and yellow boxes mean?

    Violet boxes are bull order blocks: the last down candle before a big up candle that closed above its high. Yellow boxes are bear order blocks: the last up candle before a big down candle that closed below its low. Each box covers that candle's full range, high to low, and stays on the chart until a candle closes through it.

    What does the minMove input do?

    minMove sets how big candle 2 has to be, high to low, as a multiple of ATR. The default of 1.0 means at least one full 14-bar ATR. Raise it to see only the biggest moves, or lower it to see more blocks. It's also the quickest way to thin out a crowded chart.

    How often does price come back to an order block?

    Across 648 stocks and ETFs, price came back to 84% of order blocks within 20 trading days, about a month. Most of those symbols have about 2 years of daily bars.

    When does an order block come off the chart?

    A bull block clears once a candle closes below its bottom edge, and a bear block clears once a candle closes above its top edge. A wick through the edge doesn't clear it. A new block on the same side also replaces the previous one.

    What's the difference between an order block and a fair value gap?

    A fair value gap is the empty space a fast move leaves behind. An order block is the last opposite candle right before that move. They often show up together: 54.3% of the blocks in the study also left a fair value gap on the next candle. The two indicators work well on the same chart.

    Does the Order Blocks indicator repaint?

    No. The code only looks back, so closed bars never change. On today's live bar, a candle can qualify as the big candle during the session and stop qualifying by the close, like any indicator that reads the current bar. The box draws from the next bar on.

    What timeframe should I use?

    Start on daily charts, which is what the study uses. The indicator also plots on weekly and intraday charts, and because the ATR comes from the same bars, the minMove filter scales with the chart.

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