A codicil is a written addition, amendment, or change to a will that is executed in the same manner as the original will.

With the modern day availability of word processing programs it has become just as easy to create a new will with the required changes rather than a codicil that modifies an existing will.

However, there are circumstances where it may be preferable to proceed by way of a codicil. For example, if the will-maker's capacity is in question a new will may fail; whereas, if the codicil fails, the underlying will may survive and intestacy may be avoided. Codicils are identified in the order of their creation (i.e. #1, 2, 3 etc.) and must be identified as such. Precedent forms for codicils may also be found in Wills  and Personal Planning Precedents: An Annotated Guide.