Q. Is the money for maaser and tzedakah different? If somebody took the obligation to give for tzedakah for doing Yizkor is it considered maaser or tzedakah. In expression Tzedakah tazil mimavet is it including money for maaser. Is money paid to the membership for synagogue considered money for Tzedakah or maaser?

A. Horav Shlomo Miller’s Shlit’a opinion is that if at the time one accepted or took upon himself the giving of maaser, he had in mind to include all tzedaka donations and mitzva expenditures such as the ones you describe, they will be included in the sum total of the maaser for that year.
If one keeps his giving of maaser specifically for tzedaka for the needy, however he declared from the onset that everything is being done “beli neder,” without accepting any oath or vow, he may now include also the above.
If one is uncertain whether the original maaser neder was only for tzedaka purposes or it included also all mizvos expenditures, the Rov maintains that one should be matir neder or annul the vow done, and specify that all subsequent actions are done “beli neder” and include mitzva dues.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a