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RSI settings: which length and levels to use (14, 7, 21, 70/30)

RSI settings explained: what length 14, 7 and 21 change, when to use 70/30 or 80/20 levels, how timeframe matters, and the smoothing options in SuperCharting.

The standard RSI settings are a length of 14 with the overbought line at 70 and the oversold line at 30. A shorter length such as 7 or 9 makes RSI swing wider and touch the extremes more often, and a longer one such as 21 makes it calmer. The levels do a separate job: 80 and 20 give fewer, more stretched readings than 70 and 30. There is no best RSI setting, only the one that fits your symbol, timeframe and way of trading. This page shows what each choice changes and where to set it in SuperCharting.

What RSI length changes

RSI averages gains and losses with Wilder's smoothing, so each new bar carries a weight of 1 divided by the length. At length 14 the newest bar is 7.1% of the average. At 7 it is 14.3%, and at 21 it is 4.8%. A bigger weight on the newest bar moves RSI further on each move.

A made-up example shows the gap. Suppose a symbol chops up and down by 1 point, so RSI sits near 50, and then closes up 2 points for eight bars in a row:

Same prices, three different readings. At 70/30 all three are overbought. At 80/20 only the 7 and the 14 are, and the 14 only just. That is why "RSI is above 70" says little until you know the length behind it. The calculation behind RSI is in the RSI indicator guide.

Past results do not guarantee future results, and a setting that fits last year's chart may not fit next year's.

Common length choices

• 14: Wilder's original and the default in nearly every platform, so your readings match other traders'.
• 7 or 9: faster. Useful when you want earlier warning on short swings, with more false extremes.
• 21 or 25: slower. Fewer touches of the bands, so each one stands out more.
• 2 to 4: very short lengths used by some mean-reversion traders. RSI then jumps between near 0 and near 100, so the 70/30 bands lose their usual meaning.

SuperCharting's library also has Stochastic RSI (RSI Length 14, Stochastic Length 14, K and D of 3) and Connors RSI (RSI Length 3, UpDown Length 2, ROC Length 100). Both start from a short RSI and are scaled differently from plain RSI, so their bands do not mean the same thing.

70/30 or 80/20 levels

The bands are only thresholds you choose. Moving them is the other way to change how often RSI "signals".

• 70 / 30: the default. Fine for ranging markets and for most daily charts.
• 80 / 20: fewer readings, so each is more stretched. Often chosen when RSI keeps pinning against 70 in a strong trend.
• 60 / 40: sometimes used as the working zone of a trend. In an uptrend RSI tends to hold above 40 on dips, and in a downtrend to stall below 60.

For a trending stock such as NSE:RELIANCE in a long rise, an RSI over 70 can last for weeks, so "overbought" is not by itself a reason to expect a turn. In a sideways market the same reading is more likely to be followed by a pullback. These are descriptions of how RSI behaves, not signals.

How timeframe changes RSI

RSI counts bars, not minutes. RSI 14 on a 5m chart covers 70 minutes, on 1h about two trading days, and on 1D about three weeks. The same length on different charts answers different questions.

• On NSE:NIFTY 1D, RSI 14 describes the last three weeks. It moves slowly and reads as a bias.
• On NSE:NIFTY 15m, the same setting reacts to the last few hours and crosses 70 or 30 many times a week.
• A common habit is to use RSI on a higher timeframe for the bias and a lower one to time entries; a multi-chart layout shows both at once.
• Some scalpers on XAUUSD 1m shorten the length because 14 one-minute bars is only 14 minutes of price.

How to change RSI settings in SuperCharting

1. Open a chart, for example NSE:BANKNIFTY on the 1h interval.
2. Click Indicators, type "rsi" and click Relative strength index.
3. Hover the legend line (it reads "RSI 14 close") and click the gear for Settings.
4. On Inputs, change RSI Length from 14 to the number you want to test, and set Source if you do not want the close.
5. Under Smoothing, Type picks the average drawn over RSI. The choices are None, SMA, SMA + Bollinger Bands, EMA, SMMA (RMA), WMA and VWMA. The built-in starts on SMA with Length 14, drawn in yellow. Set Type to None to remove it. BB StdDev (2) only applies to SMA + Bollinger Bands.
6. On Style, edit the RSI Upper Band, Middle Band and Lower Band values: 70, 50 and 30 become 80, 50 and 20 if you prefer.
7. Click Ok. To go back, open Settings, click Defaults and choose Reset settings.

Remember that Calculate Divergence is off by default, and that an indicator alert runs the script with its default inputs, so your changed length and levels do not reach an alert. To be told when RSI crosses your levels, save a script with those numbers as its defaults, such as this one that draws a fast and a slow RSI together:

//@version=6
indicator("RSI two lengths", "RSI 2x")
srcIn  = input.source(close, "Source")
lenA   = input.int(14, "Length A", minval = 1)
lenB   = input.int(7,  "Length B", minval = 1)
upper  = input.int(70, "Upper level")
lower  = input.int(30, "Lower level")
rA = ta.rsi(srcIn, lenA)
rB = ta.rsi(srcIn, lenB)
plot(rA, "RSI A", color.purple)
plot(rB, "RSI B", color.orange)
hline(upper, "Upper")
hline(50, "Middle")
hline(lower, "Lower")

The RSI indicator guide has the complete crossing-alert script and the steps to create the alert. If you smooth RSI or run another indicator on it, see indicators on indicators.

Testing your RSI settings

Do not pick a length because it looks good on the last month. The built-in RSI strategy on the Strategies chip has Length 14, Oversold 30 and Overbought 70 as inputs. Change them, open the Strategy Tester and compare results across several symbols and years, with Commission and Slippage set. The backtesting guide explains why a setting that wins only on one stretch of history is probably fitted to it.

Frequently asked questions

What are the best RSI settings for day trading?

There is no proven best set. Day traders often keep 14 and use 80/20 levels to reduce noise, or shorten the length to 7 to 9 for faster swings. Whichever you pick, test it on your own symbol first.

Is RSI 14 better than RSI 7?

Neither is better. 14 is the common reference, so it is easier to compare. 7 reacts faster and reaches the extremes more often, so it needs wider levels or a filter.

Why does my RSI read differently on another platform?

Check the length, the source and the amount of history loaded. RSI is a running average, so the early bars depend on where the calculation starts and can differ slightly until enough bars have passed.

Does the SuperCharting RSI have a moving average line?

Yes. The Smoothing group has a Type (SMA by default) and a Length (14), and the line is drawn over RSI. Change the type to EMA, WMA or another option, or choose None to hide it.