PSX Upper & Lower Lock Calculator
THE STOCK
How far it can move in a day
The base is the previous close (LDCP).
Previous close is not available, so this is an example. Enter your own price.
Waiting for a market price for PSO. Until it arrives, or if the symbol is not listed, the numbers below use an example price. Type your own price to override it.
THIS SESSION
324.62 to 396.76
10% each way from Rs 360.69: Rs 36.07 up or down.
AGAINST PSX'S FEED
No feed band right now
The feed does not carry price limits for this stock right now, so only the formula is shown.
CHEAP STOCKS MOVE MORE
Under Rs 10, the Re. 1 floor sets the limit
The limit is the higher of 10% and Re. 1. Below Rs 10 the Re. 1 is the bigger share of the price: a Rs 5 stock can move 20% each way in a day.
Where the Re. 1 floor applies
| Previous close | Rule | Move | Lower lock | Upper lock |
|---|---|---|---|---|
| Rs 5.00 | Re. 1 floor | Rs 1.00 (20%) | 4.00 | 6.00 |
| Rs 8.00 | Re. 1 floor | Rs 1.00 (12.5%) | 7.00 | 9.00 |
| Rs 10.00 | 10% | Rs 1.00 (10%) | 9.00 | 11.00 |
| Rs 25.00 | 10% | Rs 2.50 (10%) | 22.50 | 27.50 |
| Rs 50.00 | 10% | Rs 5.00 (10%) | 45.00 | 55.00 |
| Rs 100.00 | 10% | Rs 10.00 (10%) | 90.00 | 110.00 |
| Rs 360.69Yours | 10% | Rs 36.07 (10%) | 324.62 | 396.76 |
| Rs 500.00 | 10% | Rs 50.00 (10%) | 450.00 | 550.00 |
| Rs 1,000.00 | 10% | Rs 100.00 (10%) | 900.00 | 1,100.00 |
A lower limit is never allowed below one paisa. These rows use the standard rule; the exchange can set a different band for a particular security.
The PSX price limit rule
Under Regulation 19.3 of the PSX Regulations, a stock cannot trade more than 10% or Re. 1, whichever is higher, away from its previous day's closing price. The limit was 5% until January 2020, rose to 7.5% by March 2020, and was lifted to 10% in five fortnightly steps between May 27 and July 22, 2024 (PSX notice N-477). It covers the regular, futures and SIFC markets. For ETFs the percentage is applied to the fund's net asset value rather than its market price.
- LDCP
- previous day's closing price
- Move
- the higher of 10% × LDCP and Rs 1
- Tick
- one paisa (Rs 0.01); the limit is rounded to the nearest tick
Because the price must be a whole number of paisa, the calculation is rounded half up: a previous close of Rs 44.75 gives an upper limit of 49.225, which PSX shows as Rs 49.23.
Worked examples, checked against PSX's own figures
For a previous close of Rs 360.69, 10% is Rs 36.069, far above Re. 1, so the allowed move is that amount: lower lock Rs 324.62, upper lock Rs 396.76. For a stock that closed at Rs 5.96, 10% is only Rs 0.60, so the rupee floor wins: the limits are Rs 4.96 and Rs 6.96, a move of 16.8% each way. The two rules meet at Rs 10.00.
The table compares the calculator with the Circuit Breaker range PSX itself displayed on each company page on Saturday, October 31, 2026. The market was closed that day, so these are the figures for the Friday, October 30, 2026 session, each built from the previous close shown.
| Stock | Previous close | PSX lower | PSX upper | Calculator |
|---|---|---|---|---|
| OGDC | 306.21 | 275.59 | 336.83 | Exact match |
| HUBC | 194.04 | 174.64 | 213.44 | Exact match |
| PSO | 360.69 | 324.62 | 396.76 | Exact match |
| MEBL | 526.08 | 473.47 | 578.69 | Exact match |
| DCL | 8.72 | 7.72 | 9.72 | Exact match |
| KEL | 5.96 | 4.96 | 6.96 | Exact match |
| WTL | 0.95 | 0.01 | 1.95 | Exact match |
DCL and KEL show the Re. 1 floor at work, and WTL shows the last rule in the formula: a Rs 0.95 stock cannot fall by Re. 1, so its lower limit is held at one paisa.
What happens at the limit, and market-wide halts
When a stock reaches its upper lock, buyers outnumber sellers and trades cannot go higher that session. At the lower lock it is the reverse: if no one will buy at the lower limit, a seller simply cannot exit that day, whatever stop-loss they set. That is why position size matters on volatile stocks, and why the position size calculator asks for your risk and stop. The limit also caps how far a stock can travel, so a target outside it takes more than one session; see the pivot point calculator and Fibonacci calculator for levels inside the band.
There is a second, market-wide safeguard. If the KSE-30 index moves 5% from the previous trading day's close, PSX halts all equity and equity-based derivative markets and cancels every outstanding order. On March 9, 2026 the halt started at 9:22:15 AM after a 5% fall, the pre-open session began at 10:22:15 AM and trading reopened at 10:27:15 AM (notice N-279). A halt after a 5% rise on April 17, 2020 also lasted 60 minutes with a five-minute pre-open (notice N-505). PSX's January 2020 design paper described more conditions: the move had to be held for five consecutive minutes, it was measured from the index's opening value, the pause was to be 45 minutes, and no halt applied in the last hour of trading. The two notices do not repeat those conditions and the halts ran for 60 minutes, so treat the 2020 paper as history and check the current regulation if it matters to you.
For when the market opens and closes see PSX market hours and trading calendar, and to read what a quote screen means see how to read a PSX stock quote.
Using the limits when you trade
Work out the band before the market opens. A stock whose previous close is Rs 360.69 cannot trade below Rs 324.62 or above Rs 396.76 in that session, so that is the hardest bound on a one-day gain or loss. It is a bound for the day, not the week: a stock can lock lower or higher several sessions in a row, and each new close resets the band.
- Treat a lock as information, not a forecast. A stock stuck at its upper lock shows heavy demand that day. It does not tell you what happens tomorrow, and a late buyer may never get filled at the limit.
- Expect big moves around news. Results, dividends, bonus issues and mergers are the usual reasons a stock runs to a limit. Read the announcement first with the guide on PSX company announcements.
- Size for the lock. If a stock can fall 10% in a day and you cannot sell, your position should be small enough to survive that. Choose the share count with the position size calculator.
- Cheap stocks swing harder. Under Rs 10 the Re. 1 floor allows a bigger percentage move, so a Rs 5 stock can move 20% in a day, twice the percentage limit of a dearer stock. Check the table above before you trade one.
Sources and assumptions
Rule and sample limits checked against PSX notices and the PSX data portal on October 31, 2026.
- PSX notice N-477 (May 20, 2024): security-wise circuit breakers raised to 10% or Re. 1 under clause 19.3
- PSX notice of November 7, 2022: tick size of one paisa; circuit breaker prices rounded to the nearest tick; Regulation 19.3(a), previous day's closing price
- PSX presentation, Introduction of Market Halts and Widening of Circuit Breakers (January 13, 2020): the original design, now historical
- PSX notice N-279 (March 9, 2026): market halt after a 5% fall in the KSE-30 from the previous trading day's close
- PSX notice N-505 (April 17, 2020): market halt after a 5% rise in the KSE-30
- Prices and limits: Investify's PSX market feed (delayed for visitors who are signed out)
- PSX data portal: circuit breakers by company
The exchange sets the limits that apply on the day. Where this calculator and the exchange differ, the exchange is right. Results are estimates for information and planning only, not tax, legal or investment advice. Check your own case with a tax adviser, your broker or the official source before acting.
FAQ
PSX Upper & Lower Lock Calculator: common questions
What are the upper lock and lower lock on PSX?+
They are the highest and lowest prices a stock can trade at during one session. PSX calls them circuit breakers. Once the price reaches the upper lock no trade can happen above it that day, and once it reaches the lower lock no trade can happen below it. Orders can still be placed inside the allowed range.
What is the PSX circuit breaker limit in 2026?+
10% either way or Re. 1 either way, whichever is higher, measured from the stock's previous closing price. PSX raised the limit from 7.5% to 10% in five steps between May 27 and July 22, 2024, under Regulation 19.3. The Re. 1 rule still applies, so any stock priced below Rs 10 can move by a full rupee.
How is the upper and lower limit calculated?+
Take the previous close, work out 10% of it, and compare with Re. 1. The larger amount is the allowed move. Add it to the previous close for the upper limit and subtract it for the lower limit, then round to the nearest paisa. For a previous close of Rs 360.69, 10% is Rs 36.069, so the limits are Rs 324.62 and Rs 396.76.
Why can a cheap stock move more than 10% in a day?+
Because the limit is 10% or Re. 1, whichever is higher. Below Rs 10, a rupee is more than 10% of the price, so the rupee amount wins. A Rs 5 stock can rise to Rs 6 or fall to Rs 4, a 20% move. The percentage and the rupee floor are equal at Rs 10.
Is the limit based on the previous close or today's open?+
The previous close (called LDCP, the last day closing price). The band does not move with the opening price or with how the stock trades during the day. Once the market has closed, the next session's base is that day's close, which is what the Next session option in the calculator uses. On the ex-date of some corporate actions the base can be adjusted, which is one reason to check the figures the exchange publishes.
What is a PSX market halt?+
It is a market-wide pause, separate from the limit on any one stock. When the KSE-30 index moves 5% from the previous trading day's close, PSX suspends all equity and equity-based markets and cancels outstanding orders. In the two halts we checked, from April 17, 2020 and March 9, 2026, the market stayed shut for 60 minutes and then reopened after a five-minute pre-open session. PSX's 2020 design paper described extra conditions (a move held for five minutes, and no halt in the last hour), which the later notices do not repeat, so check the current regulation if it matters to you.
Can I still buy or sell when a stock hits its lock?+
You can place orders at prices inside the band, but a stock locked at its upper limit usually has plenty of buyers and few sellers, and one locked at its lower limit the opposite. If you want to sell a stock that is locked lower, there may be no buyers at all. A stop-loss does not protect you from this.
Why does my broker show different limits from this calculator?+
The calculator applies the standard rule to the previous close. PSX sets narrower or security-specific limits on some securities (ETFs are priced off their net asset value, and stocks around a corporate action can be adjusted), and your broker shows what the exchange set. The market feed does not say why a particular stock differs. When Investify's PSX feed carries a different band for the stock you picked, the calculator shows the feed's range as the answer and the standard rule underneath, because the exchange's figures are the ones that count.
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