All terms
legal
Completion
The day funds transfer and the property changes hands. Keys released; title transferred at the Land Registry shortly after.
In simple terms
Move-in day, legally speaking. You don't own the property until completion happens.
Example
Auction date 5 May → completion typically by 2 June (28 days). Buyer's solicitor sends funds; seller hands over keys.
If you're buying
Make sure your bridging or cash is cleared 2–3 days before completion. Missed dates trigger interest penalties.
If you're selling
Use the 28 days to vacate and clear the property. Failing to move out by completion can void the sale.