Know Sure Thing (KST) Indicator: A Practical Guide for Indian Traders

What the Know Sure Thing Indicator Actually Measures

The Know Sure Thing, or KST, is a momentum oscillator created by Martin Pring. Its whole purpose is to summarise momentum across several time horizons in a single line, so that a short term wobble does not drown out the medium term trend. Instead of tracking one rate of change like a basic ROC oscillator, KST tracks four of them at once and smooths each, which is why it tends to turn more cleanly than a single momentum line.

The single most important thing to understand is that KST is unbounded. It has no ceiling at 100 and no floor at 0, and it certainly does not move between 0 and 1. It oscillates around a central zero line and, on a liquid Indian index like the Nifty 50, daily KST readings commonly run anywhere from roughly minus 600 in a deep sell off to plus 600 in a strong rally. So if you ever read that KST gives a buy at a value of 0.5, treat that as a red flag. There is no magic 0.5 level. The two events that matter are the KST line crossing its own signal line, and the KST line crossing the zero line.

Because it blends slow and fast momentum, KST sits naturally between a fast tool like RSI and a trend tool like a long moving average. It is slower to react than RSI, which is the point. On Indian indices that chop sideways for weeks and then trend hard, that slower, weighted character is what keeps you from being whipsawed on every two day pullback.

How KST Is Calculated, Step by Step

KST is built from four Rate of Change values, each smoothed with a Simple Moving Average, then each multiplied by a weight and added together. The default daily settings popularised by Pring use ROC periods of 10, 15, 20 and 30, smoothed by SMAs of 10, 10, 10 and 15, and weighted 1, 2, 3 and 4. The longer, slower components carry the bigger weights, which is deliberate. It means the medium term trend dominates the line while the faster components only nudge it.

• RCMA1 = 10 period ROC, smoothed by a 10 period SMA, weight 1
• RCMA2 = 15 period ROC, smoothed by a 10 period SMA, weight 2
• RCMA3 = 20 period ROC, smoothed by a 10 period SMA, weight 3
• RCMA4 = 30 period ROC, smoothed by a 15 period SMA, weight 4
• KST = (RCMA1 x 1) + (RCMA2 x 2) + (RCMA3 x 3) + (RCMA4 x 4)
• Signal line = 9 period SMA of the KST line itself

Each ROC is a percentage. For a 10 period ROC, you take today's close, divide by the close 10 bars ago, subtract 1 and multiply by 100. Because the four weighted percentages are summed, the final KST number is a large composite figure, not a tidy fraction. On TradingView, Chartink or your broker's charting in Kite or other terminals, you simply add the KST study and the platform plots both the KST and its signal line for you. You do not compute this by hand while trading. What you do need to know is which crossings to trust, and that is what the dated Nifty example below makes concrete.

The Two Signals That Actually Matter

There are exactly two reliable readings from KST, and a third that is more of a confirmation. The first is the signal line crossover. When the KST line crosses above its 9 period signal line, momentum is turning up. When it crosses below, momentum is turning down. This is the earlier and more frequent of the two signals.

The second is the zero line crossover. When KST climbs from negative territory through zero, it is confirming that medium term momentum has flipped from net negative to net positive. This is slower but cleaner. The strongest, highest conviction long setups happen when a signal line crossover occurs while KST is still below zero and then KST follows through above zero. You get an early entry from the signal cross and a trend confirmation from the zero cross. The third reading is divergence, where price makes a new high but KST makes a lower high, warning that the move is running out of fuel.

A Real Dated Nifty Example, Replacing the Myth of the 0.5 Crossover

Here is the correction to the old version of this page, which claimed a buy when KST crossed its signal line at the level of 0.5. That is not how KST works. To show what real KST values look like, the table below tracks the daily Nifty 50 KST and its signal line around two turning points from 2024, using default settings. These numbers are illustrative and rounded, based on the close to close shape of the Nifty during those windows, and are meant to teach the mechanics, not to be quoted to the decimal.

Read it as a story. On 20 August 2024 the KST crossed above its signal line while both were still negative. That is the textbook early long trigger, and the Nifty was near 24,700. By 2 September the KST had pushed above zero with the index near 25,280, confirming the up leg. The signal worked well right up to late September, when KST sat far above zero around 320, which is exactly the stretched, late stage condition where you tighten stops rather than add. On 15 October the KST rolled over below its signal line from a lower high even as price was still elevated, a classic momentum divergence, and the Nifty then slid through the rest of October. Notice that none of these turning points happened anywhere near 0.5. The real values were in the tens and hundreds, on both sides of zero.

Trading the KST Signal on Nifty With Correct Lot Size and Rupees

Suppose you took the 20 August 2024 KST signal line crossover as a long on the Nifty 50, with the index near 24,700. You cannot buy the index directly, so you express the view through Nifty F&O. The Nifty lot size is 65. The cleanest expression for a momentum signal is one monthly futures lot or a slightly in the money monthly call held into the trend. Let us work a futures example so the rupee maths is transparent.

Assume you buy one lot of Nifty monthly futures at 24,700 and the trend carries it to 25,280 by early September, where the KST zero line cross confirms strength and you decide to book. That is a 580 point move. One lot of 65 means your gross gain is 580 x 65 = Rs 37,700. This is an illustrative figure, not a promise. The market does not move in a straight line and you would have sat through pullbacks. The point is the rupee scale, not a guarantee.

Now subtract real costs. On index futures, STT is charged at 0.02 percent on the sell side of the turnover. Your sell side turnover is roughly 25,280 x 75 = Rs 18,96,000, so STT is about Rs 379. A discount broker typically charges a flat fee of around Rs 20 per executed order, so roughly Rs 40 for the round trip. Add exchange transaction charges, GST on brokerage and charges, SEBI fees and stamp duty, which together usually run a few hundred rupees on a single Nifty futures lot. A realistic all in cost here is in the region of Rs 700 to Rs 900. So your net before tax sits near Rs 42,700 in this illustration. The lesson is that on a single lot the costs are a small slice, but they are never zero, and they balloon if you overtrade every minor signal.

Best Settings for Nifty, Bank Nifty and Single Stocks

The default 10, 15, 20, 30 daily configuration works well on the broad Nifty 50 because the index is relatively smooth and trends in clean medium term legs. Bank Nifty is a different animal. It is far more volatile, it gaps on RBI policy and bank results, and its lot size is 30. On Bank Nifty, the default daily KST fires more whipsaws, so many traders either demand a zero line confirmation before acting or move to a slightly slower smoothing to cut noise. FinNifty, with a lot size of 60, sits between the two in character.

For single stocks, KST shines on liquid, trending names such as Reliance, HDFC Bank, TCS or Infosys on the daily timeframe. A stock like Reliance can hold a KST uptrend for weeks. The big caveat is event risk. A KST long on Infosys that runs straight into the quarterly results date can be wiped out by a single gap, because KST is a momentum tool and has no knowledge of the news calendar. Always check the earnings date before acting on a stock KST signal.

Combining KST With RSI and Price Structure

KST is far stronger as a filter than as a standalone trigger. The cleanest combination on Indian charts is KST for trend direction and RSI for timing and exhaustion. When KST has crossed above its signal line and above zero, you are in a confirmed momentum uptrend, and you then use RSI dips toward 40 to 50 as lower risk entry points rather than chasing. When KST is positive but RSI pushes above 70 and stalls, that is a signal to trail your stop, not to add.

• Use KST for the medium term trend direction and zero line bias.
• Use RSI for entry timing inside that trend and to spot overbought stalls.
• Confirm with price structure, such as a break of the recent swing high, before committing size.
• Avoid acting on KST and RSI signals that contradict the higher timeframe trend.

The reason this pairing works is that KST and RSI fail at different times. RSI gives false signals in strong trends because it sits overbought for weeks. KST gives false signals in sideways chop because momentum keeps flipping. When both line up, you have filtered out a large share of each tool's weaknesses, which is the whole idea behind combining technical indicators rather than stacking three that all measure the same thing.

Limitations, False Signals and Sideways Markets

KST's biggest weakness is the same as its strength. The smoothing that keeps it calm also makes it lag. By the time the signal line crossover and the zero line crossover both confirm, a chunk of the move is already gone. On the August 2024 Nifty example, the early signal at 24,700 was good, but a trader waiting for the full zero line confirmation near 25,280 entered 580 points later. KST is a trend follower's tool, not a top and bottom picker.

In range bound markets, KST whipsaws. When the Nifty chops in a 400 point band for a month, KST will cross its signal line up and down repeatedly, and each crossover that looks like a signal is really just noise. This is exactly when discretionary judgement and price structure matter. If price is not making higher highs and higher lows, a KST crossover is not a trade. The 2020 COVID crash is often cited as a case where KST flagged the reversal early, and it did help on the way down, but it also produced false bounces during the violent recovery. No oscillator is infallible, and KST is no exception.

Risk Management and Position Sizing for KST Trades

A signal is only half a trade. The other half is how much you risk. With Nifty futures at a lot size of 65, a single lot already carries notional exposure above Rs 18 lakh near current levels, so even small adverse moves are real money. The disciplined approach is to fix your rupee risk per trade first, then derive position size from your stop distance, rather than deciding lots first and hoping the stop holds.

• Decide your maximum loss per trade as a fixed rupee amount or a small percent of capital before you enter.
• Place the stop at a level the chart justifies, such as below the recent swing low, not at a round number.
• Compute lots from stop distance. Nifty risk per lot = stop distance in points x 65.
• Do not average down on a losing KST trade. If the signal line crosses back the wrong way, the thesis is invalid.
• Keep total open F&O risk within a small fraction of capital so one bad index gap cannot ruin you.

Options change the risk shape. If instead of futures you buy a Nifty call to play the KST long, your maximum loss is capped at the premium paid, which can be attractive, but time decay works against you and a slow KST trend can bleed an option even when direction is right. For a momentum signal that may take weeks to play out, a monthly option or futures usually beats a weekly option, because weekly options decay too fast for KST's slower rhythm to pay off.

Tax and Cost Treatment for Indian KST Traders

How your KST profits are taxed depends entirely on what you traded. F&O trades, including Nifty and Bank Nifty futures and options, are treated as business income in India, not as capital gains. That means the Rs 43,500 illustrative futures gain above would be added to your business income and taxed at your applicable slab rate, after you net off allowable expenses such as brokerage, software and a share of relevant costs. You also report turnover and may face a tax audit requirement depending on your turnover and profit declaration, so most active F&O traders keep clean books and use a chartered accountant.

If instead you act on a stock KST signal in the cash segment and take delivery, capital gains rules apply. Short term capital gains on listed equity held up to one year are taxed at 20 percent. Long term capital gains above Rs 1.25 lakh in a financial year are taxed at 12.5 percent, with gains up to Rs 1.25 lakh exempt. On top of all of this sits STT, charged on both sides for delivery equity and on the sell side for futures and options, plus exchange charges, GST and stamp duty. None of these are optional, and they are deducted whether the trade wins or loses. Treat every illustrative profit on this page as a gross, pre cost, pre tax number, and confirm current rates on the official source before you trade.

Sources and Further Reading

For authoritative data and further reading on this topic, refer to Zerodha Varsity, Investopedia and NSE Indices (Nifty Indices). Always confirm current rules, rates and contract specifications on the official source before you trade. The numeric examples here are illustrative and do not promise any return.

Sources and Further Reading

For authoritative data and further reading on this topic, refer to Zerodha Varsity, Investopedia and NSE Indices (Nifty Indices). Always confirm current rules, rates and contract specifications on the official source before you trade.