IPO GMP Calculator
The grey market premium, or GMP, is the extra amount per share that people in the unofficial grey market pay for an IPO's shares before they list. It is the number most applicants look at to guess how an IPO might open. This calculator turns a GMP into the figures that matter to a bid: how many shares you are applying for, how much money that needs, what listing price the GMP implies, and what the gain or loss would be in rupees and as a percentage.
Pick a current IPO to fill in its price, lot size and latest GMP, or type your own numbers. You can see the real GMP history for any IPO on its GMP tab, and how reliable GMP has been on our GMP track record page.
Last reviewed: 30 October 2026
Use the upper end of the price band.
Use a minus sign if the grey market quotes a discount, for example -15.
How the numbers are worked out
The calculator uses four inputs and three formulas. Nothing is stored: everything is worked out in your browser.
- Shares in the bid = lot size × number of lots.
- Money needed = issue price × shares. This is the amount blocked in your account at the issue price.
- Implied listing price = issue price + GMP (never below zero). GMP % = GMP ÷ issue price.
- Notional gain or loss = GMP × shares, before brokerage, charges and tax.
Worked example: an issue price of ₹150, a GMP of ₹30, a lot of 100 shares and two lots. Shares = 200. Money needed = ₹30,000. Implied listing price = ₹180. GMP % = 20%. Notional gain = ₹6,000, or ₹3,000 per lot.
What it leaves out matters. You have to be allotted shares first (see the allotment probability calculator), the shares list at a price the market decides on the day, and costs and tax come off any gain.
Frequently asked questions
What is GMP in an IPO?
GMP stands for grey market premium. It is the extra amount, per share, that people trading in the unofficial grey market are willing to pay for the shares before they list, over the IPO's issue price. A GMP of ₹30 on an issue price of ₹150 means the grey market is quoting about ₹180 for the share.
How do I calculate profit from GMP?
Multiply the GMP by the number of shares in your bid. The shares in a bid are the lot size times the number of lots. With a GMP of ₹30 and a bid of 200 shares (two lots of 100), the notional gain is ₹30 × 200 = ₹6,000, which is 20% of the issue price. A negative GMP gives a loss in the same way.
Is the GMP the same as the listing price?
No. GMP only hints at where the grey market thinks the shares may list. The real listing price is set on listing day by the exchange's opening session and often differs from issue price plus GMP, in either direction. GMP also keeps changing until listing.
Can I be sure of the GMP profit if I apply?
No. You first have to be allotted shares, and in an oversubscribed IPO many applicants receive none. The gain also assumes you sell at the implied listing price, which may not be the price you get. Use the number as an illustration, not a prediction.
Does this calculator include brokerage and tax?
No. Brokerage, exchange charges and tax on any gain are extra, and they depend on your account and how long you hold the shares. The result is the gross notional gain or loss before all of them.
How accurate is GMP?
It is unofficial and unregulated, so it is only as good as the people quoting it. Our GMP track record page compares the last GMP before each tracked IPO closed with the price it actually listed at, so you can see how far off it has been.