Tzedakah is the obligation to give. Ma'aser kesafim is the specific formula, traditionally ten percent of net income, that tells you how much. The two work together but answer different questions: tzedakah asks whether you're required to give, and ma'aser answers exactly how much of your income that requirement should translate into.
That distinction matters once you move from the idea of giving to actually budgeting for it. Below, we'll walk through where the ten percent figure comes from, how to calculate it against your real income, when Jewish law allows for less, and how to turn the number into a habit rather than a one-time calculation you never revisit.
What Is Ma'aser Kesafim and How Is It Different From Tzedakah?
Ma'aser kesafim is a structured formula, typically ten percent of net income, set aside specifically for charitable giving. Tzedakah is broader: it's the underlying obligation to help those in need, regardless of any specific percentage.
Where Ma'aser Kesafim Comes From in Jewish Law
The earliest scriptural precedent for tithing at all comes from Jacob's vow in Genesis 28:22, where he promises to give a tenth of everything he receives. That precedent shaped agricultural tithing, which is a direct Torah commandment. Tithing money specifically is a different story. Unlike agricultural tithing, most halachic authorities treat ma'aser kesafim as a rabbinic custom rather than a Torah-mandated law, one that developed by analogy to the agricultural tithe once Jewish life moved away from farming as the main source of income. The clearest classical source for ma'aser kesafim appears in the Shulchan Aruch, Yoreh De'ah 249, with additional guidance from later poskim who worked out how the custom should apply to modern forms of income. That custom-versus-law distinction matters practically, since it's part of why the specific percentage and its exceptions have always had more flexibility built in than a strict biblical command would allow.
How to Calculate Your Ma'aser Kesafim
The calculation starts with your net income, not your gross income, and from there, a few practical questions determine the exact number.
Starting With Net Income, Not Gross
Business expenses and the basic costs of running your household come out first. Only what remains after those deductions counts as the income from which your ma'aser is calculated. This isn't a loophole, it's built into the halacha itself, since the goal has always been sustainable giving rather than giving that puts your own stability at risk.
What Counts as Income for Ma'aser Purposes
Wages, bonuses, business profit, rental income, and most investment returns all count. Freelance and gig income count the same way regular employment does, calculated on what's left after legitimate business expenses. A stock windfall or a one-time bonus counts too, even though it doesn't repeat month to month, since the obligation is tied to income received rather than predictable income. Gifts and inheritance are more situational, since whether they count often depends on the size of the gift and the giver's intent, which is a detail worth checking with a rabbinic authority rather than assuming either way. Social security and similar government support are also treated inconsistently across different halachic opinions, so this is another area where asking rather than guessing is the safer route.
The Ten Percent Standard and the Twenty Percent Ceiling
Ten percent of net income is the standard most people use as a baseline. Twenty percent is generally treated as the ceiling, the point past which most poskim advise against going, specifically to make sure a donor doesn't compromise their own financial footing in the name of generosity. The number itself is meant to be a floor and a guardrail at the same time, not a target to maximize regardless of circumstance.
A Simple Example: Calculating Ten Percent
The math itself is straightforward once the deductions are done. Say your annual take-home pay after taxes, business costs, and other allowable deductions comes to $60,000. Ten percent of that is $6,000 for the year, or $500 a month. If your income rises to $70,000 the following year, the number moves with it, $7,000 for the year, without needing to recalculate the underlying principle each time. The formula stays fixed, only the input changes.
Calculating Ma'aser as a Couple or Household
For married couples, the more common approach is to calculate ma'aser on combined household income rather than splitting it by each spouse's individual earnings. This matters most when one spouse earns significantly more than the other, since calculating separately could understate the household's actual giving capacity. Couples who keep entirely separate finances sometimes calculate individually instead, but combining income before applying the percentage is the more widely followed practice, and it also simplifies the bookkeeping since there's only one number to track rather than two.
Does a Tax Deduction Change What You Owe?
A common point of confusion is whether claiming a charitable donation on your taxes changes your ma'aser math. It doesn't. The ten percent is calculated on your net income before any charitable tax deduction is applied, not after, since the deduction is a benefit from the tax system rather than a change to the income you actually earned. In other words, a $6,000 gift that later reduces your taxable income doesn't mean your original ma'aser obligation was somehow smaller than $6,000. The two systems, halachic obligation and tax policy, run independently of each other, and treating them as connected is one of the more common calculation mistakes people make.
When Jewish Law Allows You to Give Less Than Ten Percent
Financial hardship changes the calculation. Unexpected medical costs, a period of lost income, or the burden of supporting older children who still live at home are all situations where giving less than ten percent is not just tolerated but expected.
Protecting Your Own Financial Stability First
The underlying principle is straightforward: tzedakah should never push the giver into needing tzedakah themselves. Covering your own basic needs comes first, and only the amount left over after that is what your ma'aser obligation applies to. This isn't a workaround to avoid giving, it's the actual halachic framework, and building a sustainable practice starts with getting this order right.
In practice, this might look like someone who normally gives ten percent scaling back to five percent for a year after a job loss, then returning to the full amount once their income stabilizes. The obligation flexes with real circumstances rather than staying fixed regardless of what's happening in a person's life, which is part of why consulting a rabbinic authority during a genuine hardship is encouraged rather than treated as a sign of falling short.
Maaser Kesafim Guidelines: What It Does Not Cover
Volunteering your time or donating goods are real, valuable forms of tzedakah, and tzedakah's broader definition includes exactly this kind of non-financial giving. But none of it counts toward your ma'aser calculation, which is strictly a financial tithe measured against your net income. The two obligations run in parallel rather than substituting for one another, so a busy volunteer schedule doesn't reduce what you owe financially, and a large financial gift doesn't replace the value of showing up in person. The same logic applies to in-kind donations like furniture, food, or clothing, they matter, but they're valued and treated separately from the cash tithe rather than folded into the same ten percent figure.
Building a Sustainable Giving System
A giving habit that survives past the first few months usually has two things behind it: a record-keeping system and a clear sense of where the money is actually going.
Keeping Records and Setting a Rhythm
A simple spreadsheet or budgeting app that tracks income alongside contributions makes the yearly math far less stressful than trying to reconstruct it from memory. Reviewing it on a set schedule, monthly or quarterly, makes it a normal part of your finances instead of a once-a-year scramble. Automating the transfer, whether through a recurring donation or a standing transfer into a separate giving account, removes the habit from willpower entirely, so the ma'aser gets set aside the same way a retirement contribution or a bill payment would, before it has a chance to get absorbed into everyday spending.
Choosing How to Direct Your Ma'aser Once You've Calculated It
Once the number is set, the next decision is where it goes, whether that's Torah education, a family member facing hardship, a synagogue, or a broader organization doing this work at scale. Some donors also prefer that their identity stay hidden from whoever receives the support, which is its own well-established practice worth understanding on its own terms.
Our guide to giving in secret and why it ranks so highly covers exactly how that works in practice.
Rambam's eight-level framework for ranking how you give is a useful next step here too, since knowing your number is only half the equation, the other half is making sure the method behind the gift protects the dignity of whoever receives it.
Turning the Ten Percent Principle Into a Habit
Knowing the difference between tzedakah and ma'aser is only useful once it changes how you actually give. The percentage isn't meant to be a one-time calculation you do and forget, it's meant to become a rhythm that adjusts as your income does, year after year.
That rhythm looks different for everyone. For some, it's a fixed monthly transfer tied to a salary. For others, especially those with variable or business income, it's a quarterly review that keeps the number honest as circumstances change. What matters more than the exact system is that there is one, since a percentage without a routine behind it tends to disappear into everyday spending quietly.
18.fund, in collaboration with the Shabata Demalkata Foundation, makes it simple to turn that rhythm into consistent action, whether through a structured monthly gift sized to your own ma'aser calculation or a one-time contribution that reflects where your finances stand right now.
Calculate Your Ma'aser and Set Up Your Monthly Giving →
Frequently Asked Questions
Do I calculate ma'aser before or after taxes?
After taxes. Ma'aser is calculated on net income, the amount you actually have available, not your gross pay before deductions.
Does ma'aser apply to money I received as a gift or inheritance?
It depends on the size of the gift and the giver's intent behind it. This is one of the more situational areas of the calculation, so it's worth checking with a knowledgeable rabbinic authority rather than assuming either way.
Can I count money I've already given to family members in need toward my ma'aser?
Generally, yes, as long as the support meets the standard of genuine charitable assistance rather than an ordinary gift or expected family expense.
What if my income varies each month, as with a business?
Calculate against your average income over a set period, such as a quarter or a year, rather than trying to tithe each month separately. This keeps the obligation consistent even when the income behind it isn't.
Is there a specific formula for ma'aser if I'm self-employed?
Self-employed income is calculated the same way as any other net income, revenue minus legitimate business expenses, before the ten percent is applied. The main difference is that self-employed givers usually need to track this more actively themselves, since no employer is withholding for reference.
Can I give more than twenty percent of my income?
Yes. Twenty percent is treated as a ceiling meant to protect the giver, not a hard legal limit, and Jewish tradition has always encouraged generosity beyond it once your own financial needs are genuinely secure.
Does ma'aser have to be given all at once, or can I split it up over the year?
It can be split up. Many people find it easier to sustain the habit by setting aside a portion with each paycheck rather than calculating and giving the full amount once a year.
Do minors or students need to give ma'aser?
Not unless they have their own independent income. That said, many families use small amounts of a child's allowance to introduce the habit early, even before it becomes a formal obligation.
Can secular charitable donations count toward my ma'aser calculation?
Opinions vary here, and it often depends on whether the organization's work genuinely supports people in need in a way consistent with the values behind tzedakah. This is worth a direct conversation with a rabbinic authority rather than a blanket assumption.
What happens if I fall behind on setting aside ma'aser for a period of time?
Jewish tradition treats this as something to catch up on rather than something to write off. Calculating the total shortfall and setting a realistic plan to close the gap over time is the standard approach.