The untaxed-plan cap is the maximum amount of the untaxed elements of your superannuation lump sum payments which will be subject to concessional tax rates.
For 2012-13, the untaxed-plan cap is $1.255 million. The cap is indexed to average weekly ordinary time earnings (AWOTE) and rounded down to the nearest multiple of $5,000. See Key superannuation rates and thresholds.
There is a separate untaxed-plan cap for each superannuation fund you have. This means that, for each fund, the untaxed elements which make up your superannuation payments will be taxed at a concessional rate until these untaxed elements reach the untaxed-plan cap amount ($1.255 million plus future indexed increases). Amounts above this limit are taxed at the top marginal rate.
If you roll over an amount from one superannuation fund to another, any untaxed element that is part of that amount will count towards the untaxed-plan cap for the fund from which the amount was rolled over.