Plain version: every plan starts with the core; the letters differ in which extra gaps they fill. Learn the few extras that set the plans apart.
Three extras to sort the plans:
Part A deductible: Plans B, C, D, F, G and N pay it; Plan M pays 50%; Plan K pays 50% and Plan L 75%.
Part B excess charges (what a doctor who does not accept assignment may bill above the approved amount, within the legal limit): Plans F, high deductible F and G pay 100%. Plans D, M and N do not.
Part B deductible: a policy that covers it cannot be sold to anyone newly eligible for Medicare on or after January 1, 2020, so Plans C, F and high deductible F are closed to them. Plan G and high deductible Plan G remain available. People eligible before 2020 can still buy C and F if offered.
Plans K and L (cost-sharing plans): they pay 50% (K) or 75% (L) of the Part A deductible and of several other cost-sharing items until a yearly out-of-pocket limit is reached. After that, the plan pays 100% of Part A and Part B cost sharing for the rest of the year. Plan L's limit is lower than Plan K's, and both limits are indexed each year.
Plan N copayments: the insured pays the lesser of $20 or the Part B coinsurance for each office visit, and the lesser of $50 or the Part B coinsurance for each emergency room visit. The emergency room copayment is waived if the insured is admitted and the visit is covered as a Part A expense. Plan N has no excess charge benefit.
Foreign travel emergency (in plans such as G): covers care that begins during the first 60 consecutive days of each trip outside the United States, paying 80% after a $250 deductible, up to a $50,000 lifetime maximum. Care that begins after day 60 of a trip is not covered.