Renko bricks for FX scalping: choosing a brick size

[Fairman]

Renko bricks for FX scalping: choosing a brick size

Renko charts ignore time and only draw a new brick when price moves a set amount. Up bricks in one colour, down bricks in another. Trends look clean, and a lot of the small noise disappears. That's the appeal.

The whole thing depends on brick size. Too small, and you get a brick for every little wiggle, so the chart is as noisy as M1. Too big, and you get a few bricks a day, which is fine for swing trading but useless for scalping.

A fixed pip size is the simplest option, but it doesn't adapt to volatility. A brick size that suits EURUSD on a quiet day will be far too small on a busy one. ATR based bricks adjust to volatility, using a multiple of the ATR from a higher timeframe. That's usually better, but the brick size then changes over time, which can make comparing days harder.

Renko also has a lag built in. A reversal needs price to move two bricks in the opposite direction before it shows. That means you see turns late.

I find Renko useful as a second chart for seeing the trend clearly, not for timing entries. Time charts still show session context and news timing, which Renko hides completely.

[PTScalper]

Renko bricks for FX scalping: choosing a brick size

Renko charts ignore time and only draw a new brick when price moves a set amount. Up bricks in one colour, down bricks in another. Trends look clean, and a lot of the small noise disappears. That's the appeal.

The whole thing depends on brick size. Too small, and you get a brick for every little wiggle, so the chart is as noisy as M1. Too big, and you get a few bricks a day, which is fine for swing trading but useless for scalping.

A fixed pip size is the simplest option, but it doesn't adapt to volatility. A brick size that suits EURUSD on a quiet day will be far too small on a busy one. ATR based bricks adjust to volatility, using a multiple of the ATR from a higher timeframe. That's usually better, but the brick size then changes over time, which can make comparing days harder.

Renko also has a lag built in. A reversal needs price to move two bricks in the opposite direction before it shows. That means you see turns late.

I find Renko useful as a second chart for seeing the trend clearly, not for timing entries. Time charts still show session context and news timing, which Renko hides completely.

Hi Fairman,

You've highlighted the central paradox of trading Renko: the very mechanism that makes it visually beautiful is what creates its execution lag. Because Renko entirely strips out time, volume, and session context, it excels as a directional compass but struggles as a standalone trigger—especially in scalping, where a small delay ruins the risk-to-reward ratio.

[PTScalper]

The Brick Size Dilemma: Fixed vs. ATR

Finding the "Goldilocks" brick size is the hardest part of establishing a Renko system.

Fixed Pip Size (The Structural Problem): If you set a fixed 3-pip brick for EUR/USD, it might provide excellent, tradable waves during the London-New York overlap. But during the Asian session, it will either print almost nothing or chop sideways endlessly. The market's rhythm changes, but your lens doesn't.

ATR-Based Size (The Comparability Problem): Using the Average True Range (e.g., a 14-period ATR from an M15 or H1 chart) ensures your bricks adapt to current volatility. However, as you noted, a dynamic brick size destroys historical context. A "clean trend" on Tuesday might have consisted of 5-pip bricks, while Thursday's identical-looking trend used 12-pip bricks. This makes standardizing your stop-losses and backtesting incredibly difficult.

A Scalper's Compromise: Many day traders use a hybrid approach. They check a higher-timeframe ATR before the session begins, set a fixed brick size based on that reading (e.g., 50% of the H1 ATR), and leave it locked for the duration of the session. This provides daily adaptation while keeping intra-session charts consistent.

[PTScalper]

The Mathematics of the Reversal Lag

The "late turn" you experience is a mathematical certainty of how Renko is drawn. To paint a continuation brick, price only needs to move 1x the brick size. To paint a reversal brick, price must retrace the entire current brick and move a full brick length in the opposite direction—a 2x distance.

If your brick size is 5 pips, and the trend is up:

Price hits 1.1010. An up-brick is drawn.

To draw the next up-brick, price must reach 1.1015 (+5 pips).

To draw a down-brick, price must drop to 1.1000 (-10 pips).

For a swing trader aiming for 100 pips, sacrificing 10 pips to confirm a reversal is a cheap insurance policy. For a scalper aiming for 10 to 15 pips, waiting for a 10-pip reversal to confirm an entry means the move is likely already over. By the time the opposite-colored brick prints, you are entering at the worst possible price.

[PTScalper]

The Dual-Chart Advantage

Using Renko strictly as a "conviction filter" alongside a time-based chart is the optimal way to deploy it for short-term trading.

The Time Chart (M1 or M5): This is your execution terminal. It shows you the nuances that Renko aggressively hides: candlestick wicks rejecting a key moving average, the exact timing of macroeconomic news releases, volume spikes, and the opening volatility of major financial centers.

The Renko Chart: This is your psychological anchor. When your M1 chart gets violently choppy, the Renko chart keeps you focused on the broader structure. If the M1 chart shows a terrifying red candlestick, but the Renko chart hasn't even printed a reversal brick, you know the structural trend is still intact.

[Fairman]

Backtesting on Renko is where people get burned. Many platforms draw historical Renko bricks with information that wasn't available in real time, especially when a brick forms in the middle of a candle. Strategies that look great on historical Renko can perform very differently live. If you want to test a Renko strategy, it needs tick data and a Renko construction that builds bricks only from past ticks. Otherwise the results are closer to fiction than to a real test. If the backtest looks too clean, it probably is. Tick based construction is the only honest way to test it.

[Fairman]

Brick size also interacts with spread. If your brick is only a few times the spread, a lot of each brick's move gets eaten by costs when you trade it. For scalping, you'd want a brick size that's comfortably larger than the typical spread at your trading time. That pushes brick sizes up, which in turn makes the chart slower. There's a natural limit on how small you can go and still have something tradeable after costs. In practice that pushes Renko towards slightly longer holding scalps rather than the very short ones some people want to use it for.

[FXS HongKong Scalper]

The spread versus brick size trade off is the key point. One way to pick a number is to look at the typical M5 ATR in the hours you trade and set the brick as a fraction of it, often between a third and a half. That keeps the brick in line with the actual movement of your session, which differs a lot. A brick that suits the London morning on GBPUSD will be too big for the quiet Asian afternoon, while one sized for Asia will print dozens of bricks during London. Some traders keep two brick sizes for that reason.

[Fairman]

Brick size relative to the timeframe you'd otherwise use is one way to think about it. If you normally trade M5 and the typical M5 candle range is around five pips on EURUSD, a five pip brick gives you something with similar resolution, minus the time element. A smaller brick shows more detail but more noise. A bigger brick filters noise but can make you late. Starting with the typical candle range from your usual timeframe and adjusting from there is a reasonable approach. A week of watching both the time chart and the brick chart side by side helps with the choice.

[FXS Prop Desk]

Both brick-size problems are real, and there is a middle option some traders use: set the ATR-based size once per session, at the open, and keep it fixed until the session ends. The bricks then adapt between Asia and London, but within the session they stay comparable, so a pattern of three bricks means the same distance all morning. It also makes the journal easier, since each session has one brick size to record. The cost is that a sudden news spike mid-session is still measured with the morning's yardstick, which may be a feature rather than a bug.