Check one row of your NPS statement. See the NAV your credit implies, the rupees that did not buy units, and what the days between deduction and credit cost you.
Which day’s NAV applies to my contribution?
This page will not tell you, and that is deliberate. The rule is in the scheme’s operating guidelines and in your point of presence’s own terms, and neither could be read from this machine when the page was built - the NPS Trust NAV pages returned 404 and the NSDL charge schedule returned no document. What the page does instead is report the two dates your own statement carries, the days between them, and what the price moved by in that time. That turns "this seems late" into a specific question with a number attached, which is a much better thing to put to a provider.
My employer deducted in April and the units carry a May NAV. What did that cost me?
Look up the NAV for the deduction date in your scheme’s NAV history and enter it above. The page then shows the units the contribution would have bought on that day against the units it actually bought, and the difference is the cost - in units, permanently. That last word matters: a later gain multiplies the units you own, so it cannot give back units you never bought. Enter today’s NAV as well and the same difference comes out in rupees.
The units do not match my contribution divided by the NAV. What came off?
Something taken before the money was invested. NPS carries charges at more than one point - the point of presence takes one on a contribution, the record-keeping agency takes others - and a statement generally shows the units that survived rather than the deductions that produced them. This page reports the rupees that did not become units, which is a fact about your statement, and leaves the naming of them to the schedule your own provider publishes. Ask for that schedule: the figure will be the same every month, so it is worth knowing once.
Why is the NAV my credit implies more useful than the units?
Because fewer units than expected has two explanations and the units column cannot separate them. A charge taken before investment and a different day’s price both leave you short. Dividing your contribution by the units you were actually credited gives the price you effectively paid per unit: a charge moves that away from the printed NAV, while a different day moves the printed NAV itself. One figure, two diagnoses, and it is the same move every check page on this site makes.
It says I got more units than I paid for. Is that a windfall?
Almost never. The usual reading is that the amount you entered is not the whole of what was credited on that row - an employer share sitting alongside your own contribution, or a correction entry for an earlier month. Check the row for a second figure before celebrating. The page reports it as a finding rather than as good news for exactly that reason: an unexplained credit is a thing to understand, not a thing to bank.
Does this check my whole NPS account?
No, one row of it. That is a deliberate limit rather than a missing feature: a whole statement is a table, and a page that takes a pasted table gets a mistyped row producing a confident wrong verdict. One contribution, four figures you can point at, and an answer you can trust. Run it on the row that looks wrong, and then on a normal one, because a charge that appears on both is the schedule and a gap that appears on only one is worth asking about.