There are three grades of listed building in England and Wales:
- Grade I – Buildings of exceptional interest such as very fine country houses, important or old churches.
- Grade II* – Particularly important buildings of more than special interest such as most country houses, important churches or very old secular buildings.
- Grade II – These are buildings of special interest, which warrant every effort being made to preserve them. 96% of listed buildings are Grade II.
There are three grades of listed building in Northern Ireland:
- Grade A – Buildings of greatest importance to Northern Ireland including both outstanding architectural set-pieces and the least altered examples of each representative style, period and type.
- Grade B+ – Buildings which might have merited grade A status but for detracting features such as an incomplete design, lower quality additions or alterations.
- Grade B – Buildings of local importance and good examples of a particular period or style. A degree of alteration or imperfection of design may be acceptable.
There are three grades of listed building in Scotland:
- Grade A – Buildings of national or international importance, either architectural or historic, or fine little-altered examples of some particular period, style or building type.
- Grade B – Buildings of regional or more than local importance, or major examples of some particular period, style or building type which may have been altered.
- Grade C – Buildings of local importance, lesser examples of any period, style, or building type, as originally constructed or moderately altered; and simple traditional buildings which group well with others in categories A and B.