It is brought down in halacha (Orach Chaim 656) that a person is not obligated to spend more than 20% of his money on performing a positive mitzvah. Is the 20% calculated according to his total bank account, or is it calculated like ma'aser kesafim is, according to his yearly income. For example, if a certain mitzvah would cost more than 20% of the man's income for that year, but it would be less than 20% of his total bank account that he has saved up from forever, would he be obligated to perform that mitzvah?

  • Why can't it be both? Feb 5 '20 at 17:26
  • The derivation of the halacha IIRC comes from the 20% cap on tzedaka, so it would likely follow the same rules (and we know ma'aser is 10% on all wealth as it comes in)
    – AKA
    Oct 2 '20 at 11:56

The Mishnah Berura 656:8 seems to understand that normally it refers to income but not it all instances:

יותר מחומש אפילו מצוה עוברת - ומ"מ חייב להוציא עכ"פ עישור נכסיו לזה דגם בצדקה שיעור בינוני הוא מעשר ועיין במ"א וא"ר דכמו שם לענין צדקה שנה ראשונה מן הקרן מכאן ואילך מן הריוח ה"נ בענינינו ועיין בבה"ל שביררנו דר"ל דמשיעור זה בודאי אסור לפחות אבל אפשר דבענינינו דהוא מצוה עוברת גרע טפי וחייב להוציא עד חומש מנכסיו

However in his Sefer Ahavas Chesed chelek 2, 20:3 (and in the Biur Halacha in 656) he seems to qualify that this is only for investment income or savings, however a paycheck or the like, once you take what you need to live, the extra can be used even if it’s more than a fifth:

ג. ודע, דמה שהתקינו חז"ל, שלא לפזר יותר מחומש, נראה דהינו, דוקא כשמבזבז נכסי ביתו על ידי זה הפזור, כדמשמע לשון 'המבזבז'; *** אבל בדבר מועט, כגון, שיש לו איזה מלאכה או עסק קבוע, שמשתכר בה כדי מחיתו כל שבוע ויותר מעט - מתר לו לפזר היותר לצדקה, אף שהוא עולה יותר מחומש לפי ערך

R’ Shmuel Wosner in Shevet Halevi (4:64) brings a Chazon Ish who says that one should set aside a fifth of all his income to be used in the event it’s needed for a mitzvah. However, if he didn’t do that, and now he needs more money for a mitzvah, he would have to use his savings up to the amount he would’ve had if he’d set it aside all the years. He then proceeds to argue with this by saying there is no source for such a thing, especially if it’s before the time of chiyuv for the mitzvah.



It can only mean: "Give no more than 20% of what you earn as you earn it".

The alternative doesn't make sense. Suppose that, starting from 0, you earn $100. You give $20 to charity, spend $10 for yourself, and put the remaining $70 in the bank. Now, if you "tax" that $70 at 20%, then what remains at 20%, and keep going, before too long you will have next to nothing left.

  • 2
    OP knows that ma'aser kesafim is according to income; it's in the question. This is about spending max 20% to fulfill some other מצות עשה.
    – Rish
    Sep 23 '19 at 19:08

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