If you’re worried about paying for your health care in retirement, get ready to worry more. A healthy couple retiring this year at age 65 will pay $266,589 for health care in retirement, according to the 2015 Retirement Healthcare Costs Data Report by health data provider HealthView Services. That’s a 6.5% jump from HealthView’s projections a year ago. If medical costs continue their rapid rise, the tab will be even larger in the near future: Expected lifetime health care expenses will rise to $320,996 for a couple retiring in 10 years at age 65, the study found. And that’s just what you’ll pay for Medicare Parts B and D, which cover routine medical care and prescription drugs, and a Medicare supplemental insurance policy, which most Medicare recipients buy to help with co-pays and deductibles. It doesn’t include all the out-of-pocket costs that traditional Medicare doesn’t cover, including dental, vision, and hearing services, and co-pays. When you factor in those expenses, projected retirement health care costs rise to $394,954 for a couple retiring this year at age 65 and $463,849 for a couple retiring in 10 years. And those numbers don’t even count long-term care, which can add tens of thousands of dollars if you need extensive help at home or in a nursing home. To put those costs in perspective, HealthViews estimates that a couple retiring today will spend 67% of their Social Security benefits on health care costs over their lifetimes. For a couple retiring in 10 years at age 65, medical care will suck up 90% of their Social Security income. That’s troubling considering that for many, Social Security makes up the majority of their retirement income. Even for middle income and wealthier families, Social Security accounts for about one-third of retirement income. But Social Security benefits won’t be able to keep up with health care inflation. Social Security benefits have averaged a 2.6% annual cost of living increase over the past decade (and just 1.4% the past four years), while health care costs have risen more sharply. According to the Centers for Medicare and Medicaid, health care costs will rise 5% to 7% over the next eight years. HealthView numbers are higher than other surveys on health care retirement costs. In Fidelity Benefits Consulting’s annual retirement health care costs report for 2014, a 65-year-old couple retiring today will need an average of $220,000 to cover medical expenses throughout retirement. Counterintuitively, estimates of total lifetime health care costs are lower for people in poor health at retirement. HealthView’s estimates show that total retirement health care costs will be lower on average for someone with diabetes because of a shorter life expectancy. The total health care costs for a typical 55-year-old male with Type II diabetes will be approximately $118,000, compared to $223,000 for his healthy counterpart, primarily because the 55-year-old with diabetes has an expected longevity of 76, vs. 86 for a healthy male. Of course, these are just averages. You can’t know exactly what your health will be after you retire, how much medical treatments will cost you, or how long you will live. That said, even a rough guide can be a useful planning tool. So take a look at your insurance coverage. Consider the likelihood for each type of expense, as well as the average Medicare costs by age, to come up with an estimate of the savings you’ll need to fund these costs. Kaiser recently published a study on Medicare costs by age, which breaks down Medicare spending into its main components—hospitals, doctors, and drugs—and measures how much Americans spend on these services at different ages. To prepare for that spending in advance, take a look at your sources of your retirement income. If you have a health savings account, do everything you can not to touch it now but let it grow tax free. It is an excellent vehicle for funding future medical expenses. Ditto for a Roth IRA, which lets your money grow tax free. For more tips on planning for retirement health care costs, check out MONEY’s stories here, here, and here.