Price support and resistance levels are key trading tools in any market. Their roles may be interchangeable, depending on whether the price level is approached in an up-trending or a down-trending market. These price levels may be derived from many market assumptions and conventions. In pivot point analysis, several levels, usually three, are commonly recognized below and above the pivot point. These are calculated from the range of price movement in the previous trading period, added to the pivot point for resistances and subtracted from it for support levels.
The first and most significant level of support (S1) and resistance (R1) is obtained by recognition of the upper and the lower halves of the prior trading range, defined by the trading above the pivot point (H − P), and below it (P − L). The first resistance on the up-side of the market is given by the lower width of prior trading added to the pivot point price and the first support on the down-side is the width of the upper part of the prior trading range below the pivot point.
R1 = P + (P − L) = 2×P − L
S1 = P − (H − P) = 2×P − H
Thus, these level may simply be calculated by subtracting the previous low (L) and high (H) price, respectively, from twice the pivot point value:[1]
The second set of resistance (R2) and support (S2) levels are above and below, respectively, the first set. They are simply determined from the full width of the prior trading range (H − L), added to and subtracted from the pivot point, respectively:
R2 = P + (H − L)
S2 = P − (H − L)
Commonly a third set is also calculated, again representing another higher resistance level (R3) and a yet lower support level (S3). The method of the second set is continued by doubling the range added and subtracted from the pivot point:
R3 = P + 2×(H − L)
S3 = P − 2×(H − L)
This concept is sometimes, albeit rarely, extended to a fourth set in which the tripled value of the trading range is used in the calculation.
Qualitatively, the second and higher support and resistance levels are always located symmetrically around the pivot point, whereas this is not the case for the first levels, unless the pivot point happens to divide the prior trading range exactly in half.
Support and resistance is a concept in technical analysis that the movement of the price of a security will tend to stop and reverse at certain predetermined price levels
Support :
A support level is a price level where the price tends to find support as it is going down. This means the price is more likely to "bounce" off this level rather than break through it. However, once the price has passed this level, by an amount exceeding some noise, it is likely to continue dropping until it finds another support level.
Resistance :
A resistance level is the opposite of a support level. It is where the price tends to find resistance as it is going up. This means the price is more likely to "bounce" off this level rather than break through it. However, once the price has passed this level, by an amount exceeding some noise, it is likely that it will continue rising until it finds another resistance level
Identifying support and resistance levels
Support and resistance levels can be identified by trend lines. Some traders believe in using pivot point calculations.
The more often a support/resistance level is "tested" (touched and bounced off by price), the more significance given to that specific level.
If a price breaks past a support level, that support level often becomes a new resistance level. The opposite is true as well, if price breaks a resistance level, it will often find support at that level in the future.
Using support and resistance levels
This is an example of support switching roles with resistance, and vice versa:
The first and most significant level of support (S1) and resistance (R1) is obtained by recognition of the upper and the lower halves of the prior trading range, defined by the trading above the pivot point (H − P), and below it (P − L). The first resistance on the up-side of the market is given by the lower width of prior trading added to the pivot point price and the first support on the down-side is the width of the upper part of the prior trading range below the pivot point.
R1 = P + (P − L) = 2×P − L
S1 = P − (H − P) = 2×P − H
Thus, these level may simply be calculated by subtracting the previous low (L) and high (H) price, respectively, from twice the pivot point value:[1]
The second set of resistance (R2) and support (S2) levels are above and below, respectively, the first set. They are simply determined from the full width of the prior trading range (H − L), added to and subtracted from the pivot point, respectively:
R2 = P + (H − L)
S2 = P − (H − L)
Commonly a third set is also calculated, again representing another higher resistance level (R3) and a yet lower support level (S3). The method of the second set is continued by doubling the range added and subtracted from the pivot point:
R3 = P + 2×(H − L)
S3 = P − 2×(H − L)
This concept is sometimes, albeit rarely, extended to a fourth set in which the tripled value of the trading range is used in the calculation.
Qualitatively, the second and higher support and resistance levels are always located symmetrically around the pivot point, whereas this is not the case for the first levels, unless the pivot point happens to divide the prior trading range exactly in half.
Support and resistance is a concept in technical analysis that the movement of the price of a security will tend to stop and reverse at certain predetermined price levels
Support :
A support level is a price level where the price tends to find support as it is going down. This means the price is more likely to "bounce" off this level rather than break through it. However, once the price has passed this level, by an amount exceeding some noise, it is likely to continue dropping until it finds another support level.
Resistance :
A resistance level is the opposite of a support level. It is where the price tends to find resistance as it is going up. This means the price is more likely to "bounce" off this level rather than break through it. However, once the price has passed this level, by an amount exceeding some noise, it is likely that it will continue rising until it finds another resistance level
Identifying support and resistance levels
Support and resistance levels can be identified by trend lines. Some traders believe in using pivot point calculations.
The more often a support/resistance level is "tested" (touched and bounced off by price), the more significance given to that specific level.
If a price breaks past a support level, that support level often becomes a new resistance level. The opposite is true as well, if price breaks a resistance level, it will often find support at that level in the future.
Using support and resistance levels
This is an example of support switching roles with resistance, and vice versa:

If a stock price is moving between support and resistance levels, then a basic investment strategy commonly used by traders, is to buy a stock at support and sell at resistance, then short at resistance and cover the short at support as per the following example

When judging entry and exit investment timing using support or resistance levels it is important to choose a chart based on a price interval period that aligns with your trading strategy timeframe. Short term traders tend to use charts based on interval periods, such as 1 minute (i.e. the price of the security is plotted on the chart every 1 minute), with longer term traders using price charts based on hourly, daily, weekly or monthly interval periods. Typically traders use shorter term interval charts when making a final decisions on when to invest, such as the following example based on 1 week of historical data with price plotted every 15 minutes. In this example the early signs that the stock was coming out of a downtrend was when it started to form support at $30.48 and then started to form higher highs and higher lows signalling a change from negative to positive trending