Will I have to pay Stamp Duty?

The Government’s standard rules and procedures for Stamp Duty Land Tax (SDLT) apply to all Help to Buy purchases.
SDLT is payable at the time of purchase, on the full purchase price of the home. That is, the amount paid by you (the first mortgage and any cash contribution) plus the value of the Help to Buy loan.
There is no further SDLT to pay on any ‘staircasing’ repayments or repayment when the home is sold.
You should budget for SDLT on the full open market price of the property when you purchase a Help to Buy home.
Your solicitor and mortgage adviser can advise you how much the stamp Duty will be when before you purchase your new property, so you may budget for this.