What the transfer balance cap is
The transfer balance cap is a lifetime limit on the total amount of superannuation you can transfer into retirement phase — the phase where your savings support an income stream and the earnings on those savings are tax free. It has applied since 1 July 2017, and you can keep making transfers into retirement phase as long as you remain below your cap.
There are two caps to keep straight. The general transfer balance cap is the economy-wide figure set for each year. Your personal transfer balance cap is your own lifetime limit — set equal to the general cap on the day you first start a retirement-phase income stream, and adjusted differently from that point on. The two are often different amounts, which is where most confusion about “the cap” comes from.
Note
The cap limits what you transfer in — not what the account can grow to. If strong investment returns push a retirement-phase balance above your personal cap, the cap is not breached.