Share of cost is a monthly amount you must pay toward your own medical expenses before Medicaid begins covering your care. It applies to people whose income is too high for free Medicaid but who still qualify under what’s called the “medically needy” pathway. Think of it as a monthly deductible: once you’ve spent enough on healthcare to meet your share of cost, Medicaid kicks in and pays for the rest of that period’s covered services.
The term is most commonly associated with California’s Medi-Cal program, but 34 states offer some version of medically needy coverage with a similar spend-down requirement as of 2025.
How Share of Cost Is Calculated
Your share of cost is based on the gap between your monthly income and what your state considers your “maintenance need,” which is the minimum amount a person needs to cover basic living expenses like food and housing. Your county welfare or social services department takes your countable monthly income, subtracts the maintenance need allowance, and the leftover amount becomes your share of cost.
For example, if your state’s maintenance need level is $600 per month and your countable income is $1,400, your share of cost would be $800. That means you’d need to rack up $800 in medical expenses each month before Medicaid starts paying. The maintenance need levels vary by state. In 2025, the median income limit across states with medically needy programs is $511 per month, though individual states set their own figures. Married couples may also receive a spousal income allowance that adjusts the calculation.
What “Spending Down” Means
Meeting your share of cost is often called “spending down.” You don’t literally hand money to the state. Instead, you accumulate qualifying medical expenses until they equal your share of cost amount for that period. Once those expenses are verified, you become eligible for Medicaid coverage for the remainder of the budget period.
States use different budget periods for the spend-down. Some reset the clock every month, meaning you start over on the first of each month. Others use three-month or six-month windows, which is the longest federal law allows. Connecticut, for instance, uses a six-month period. A longer budget period can work in your favor because you have more time to accumulate enough expenses to clear the threshold.
What Counts Toward Your Share of Cost
The range of expenses that can count toward your share of cost is broad. In California’s Medi-Cal program, all medically necessary health services qualify, including doctor visits, hospital care, medical supplies, devices, and prescription drugs. Notably, even services that Medicaid itself doesn’t cover can count toward your share of cost, as long as they’re medically necessary. Health insurance premiums you pay out of pocket may also count in some states.
This flexibility matters in practice. If you have a $500 share of cost and fill a $200 prescription, see a specialist for $250, and pay a $50 copay somewhere else in the same budget period, those expenses together clear your share of cost. Medicaid then covers the rest of your care for that period.
How Share of Cost Gets Cleared
You don’t just tell the state you’ve spent enough. The share of cost has to be formally certified, meaning the state’s eligibility system must confirm that you’ve paid or committed to pay the full amount. In California, providers log into an online system to clear a patient’s share of cost in real time. Until that certification happens, you aren’t eligible to receive Medicaid-covered services.
You don’t always have to pay the full amount upfront. Providers can accept an “obligation agreement,” which is essentially a written promise that you’ll pay your share of cost over time or in installments. That written agreement, signed by both you and the provider, counts as meeting your obligation for certification purposes. This is especially important for months when your share of cost is high and you can’t pay it all at once before receiving care.
How It Differs From a Deductible
Share of cost resembles a private insurance deductible in some ways, but the mechanics are different. With a standard health insurance deductible, you pay a set annual amount before your plan covers most services, and that threshold resets once a year. Share of cost resets far more frequently, as often as every month, depending on your state. That means you could face the same spend-down requirement twelve times a year rather than once.
Another key difference: private insurance deductibles exist alongside monthly premiums that you pay regardless of whether you use care. Share of cost has no separate premium. You only owe anything when you actually need medical services. In months when you don’t seek care, you don’t pay your share of cost, but you also don’t have Medicaid coverage that month.
Private plans also cap your total yearly spending with an out-of-pocket maximum. After hitting that ceiling, your insurer pays 100% of covered services. Share of cost programs don’t have an equivalent annual cap because the obligation resets each budget period.
Why Some Months You Won’t Clear It
One of the most frustrating aspects of share of cost is that in months when you’re relatively healthy, you may not have enough medical expenses to meet the threshold. If your share of cost is $800 and you only need a $50 prescription that month, you’re responsible for the full cost of that prescription and don’t receive any Medicaid help. The program only activates in months when your medical expenses are high enough to push past the spend-down amount.
This creates a pattern where share of cost Medicaid functions more like catastrophic coverage. It protects you in months with significant medical needs (surgeries, hospitalizations, expensive medications) but offers little help during routine care months. People with chronic conditions that require ongoing treatment tend to clear their share of cost regularly, while those with occasional healthcare needs may rarely benefit.
How to Reduce Your Share of Cost
Because the calculation hinges on your income relative to the maintenance need level, anything that lowers your countable income can reduce your share of cost. Some states allow deductions for work-related expenses, certain disability-related costs, or dependent care. Reporting changes in income promptly to your county social services office is important, since a drop in earnings should lower your share of cost for future months.
If your income changes significantly, you may also qualify for a different Medicaid category with no share of cost at all. It’s worth asking your county eligibility worker whether other pathways apply to your situation, particularly if your income has decreased or your household size has changed.