Education

Glossary

Plain-language definitions for the terms that show up across NestPilot Foundation wedges, calculators, and education materials. Anchor links per term — link directly to a single definition from anywhere on the site.

Delayed Retirement Credits (DRC): An 8% per year increase in your Social Security benefit for each year you delay claiming past Full Retirement Age, up to age 70.; Delayed Retirement Credits add 2/3 of 1% per month — 8% per year — to your Social Security retirement benefit for every month you delay claiming past Full Retirement Age, up to age 70. For someone with FRA of 67, claiming at 70 yields a permanent 24% increase over PIA. After age 70 there is no further increase for delay; this is the cap. DRCs do not apply to spousal or survivor benefits — those have their own rules.; See also:Social Security Claiming Ages Social Security Claiming
Five-Year Rule: Two separate Roth IRA rules often conflated — one applies to earnings being qualified, one applies per-conversion to penalty-free principal access.; The "five-year rule" for Roth IRAs is two separate rules. **Rule one** applies to earnings: a Roth IRA must be open for at least five tax years (and the owner must be over 59½ or meet another qualifying condition) before earnings are qualified — that is, withdrawable tax-free. The clock starts with the first contribution or conversion to any Roth IRA. **Rule two** applies per conversion: each conversion has its own five- year clock before the converted principal can be withdrawn without the 10% early-withdrawal penalty, if the owner is under 59½. For owners over 59½ rule two is generally moot. For early retirees considering the Roth conversion ladder, the per-conversion clock is the binding constraint.; See also:Roth Conversion Basics Roth Basics
Full Retirement Age (FRA): The age at which you receive your full Social Security retirement benefit (PIA) — 67 for anyone born in 1960 or later.; Full Retirement Age is the age at which Social Security pays your unreduced retirement benefit, equal to your Primary Insurance Amount. For anyone born in 1960 or later, FRA is 67. For earlier birth years, FRA scales gradually down to 66 for those born 1943–1954. Claiming before FRA reduces your benefit (5/9 of 1% per month for the first 36 months, 5/12 of 1% per month thereafter); claiming after FRA earns Delayed Retirement Credits at 8% per year up to age 70.; See also:Social Security Claiming Ages Social Security Claiming
General Enrollment Period (GEP): January 1 through March 31 every year — the fallback window if you missed your IEP and don't qualify for an SEP.; The General Enrollment Period runs January 1 through March 31 every year. It's the fallback window for anyone who missed their Initial Enrollment Period and doesn't qualify for a Special Enrollment Period. Coverage typically begins the month after enrollment. By the time you fall back to the GEP, the Part B late-enrollment penalty has already been accruing — once activated, it stays with you for life.; See also:Medicare Enrollment Deadlines Medicare Deadlines
Health Savings Account (HSA): A tax-advantaged account paired with a High-Deductible Health Plan; contributions deductible, growth tax-free, withdrawals for qualified medical expenses tax-free.; A Health Savings Account is a tax-advantaged account paired with a High-Deductible Health Plan. Contributions are tax-deductible (or pretax through payroll), growth is tax-free, and withdrawals for qualified medical expenses are tax-free at any age. After 65, non- medical withdrawals are taxed as ordinary income (no penalty), which makes the HSA functionally a "Traditional IRA + medical wildcard" post-65. Critical rule: **Medicare enrollment of any kind disqualifies you from contributing to an HSA**. The six-month retroactive Part A backdating creates a trap for HSA contributors who delay Medicare past 65.; See also:Hsa Pre Medicare
High-Deductible Health Plan (HDHP): A health plan with deductibles and out-of-pocket maxima above IRS-set thresholds, which is the prerequisite for HSA contributions.; A High-Deductible Health Plan is a health insurance plan with deductibles and out-of-pocket maximums above IRS-set thresholds (the thresholds adjust annually). HDHPs are the prerequisite for Health Savings Account contributions — you can only contribute to an HSA in months you're enrolled in an HDHP and have no other disqualifying coverage (including Medicare). Many employers' default plans are HDHPs precisely so employees can build an HSA, which is why coordination between employer coverage, HDHP enrollment, and Medicare timing is the central HSA pre-Medicare planning problem.; See also:Hsa Pre Medicare
Initial Enrollment Period (IEP): A seven-month window centered on your 65th birthday — three months before, your birth month, and three months after — to enroll in Medicare without a late penalty.; The Initial Enrollment Period is the seven-month window for enrolling in Medicare around your 65th birthday: the three months before, the month you turn 65, and the three months after. Enroll during this window and you avoid the late-enrollment penalties for Part A and Part B. Miss the IEP without qualifying for a Special Enrollment Period and you typically wait for the General Enrollment Period (January 1 through March 31), with the Part B penalty already counting from when you first became eligible.; See also:Medicare Enrollment Deadlines Medicare Deadlines
IRMAA: Income-Related Monthly Adjustment Amount — a Medicare Part B + Part D premium surcharge for higher-income beneficiaries, based on MAGI from two years prior.; The Income-Related Monthly Adjustment Amount is a surcharge added to Medicare Part B and Part D premiums for beneficiaries whose Modified Adjusted Gross Income exceeds set thresholds. Tiers are cliffs, not smooth slopes: a single dollar over a threshold puts a household fully into the next tier for the entire year. The income that determines IRMAA is your MAGI from two years prior — so 2026 IRMAA is based on your 2024 tax return, with limited exceptions for life-changing events filed via SSA-44.; See also:Irmaa Brackets 2026 Roth Conversion Basics Irmaa Roth Basics
Medicare Advantage: Private health plans (Part C) that bundle Part A + Part B and usually Part D, in exchange for network restrictions and prior-authorization rules.; Medicare Advantage (sometimes called Part C) is the umbrella for private-insurer plans approved to provide Medicare benefits. A Medicare Advantage plan typically bundles Part A and Part B together, often includes Part D drug coverage, and frequently advertises extras (vision, dental, gym memberships). The trade-off is network restrictions, prior- authorization rules, and an annual out-of-pocket maximum that's still tens of thousands of dollars in a bad year. Switching from a Medicare Advantage plan back to original Medicare + Medigap can be difficult after the initial guaranteed-issue window — Medigap underwriting may decline.
Medicare Part A: Hospital insurance — covers inpatient hospital care, skilled nursing, hospice, and some home health.; Medicare Part A is the hospital-insurance portion of Medicare. It covers inpatient hospital stays, skilled-nursing facility care after a qualifying hospital stay, hospice, and some home-health services. Most people qualify for premium-free Part A at age 65 because they (or their spouse) paid Medicare payroll taxes for at least 40 quarters of covered employment. Even when premium-free, enrolling in Part A is the trigger that ends HSA eligibility — the rule that catches HSA contributors who keep working past 65.; See also:Medicare Enrollment Deadlines Medicare Deadlines Hsa Pre Medicare
Medicare Part B: Medical insurance — covers physician services, outpatient care, preventive services, and durable medical equipment.; Medicare Part B covers most physician services, outpatient care, preventive screenings, and durable medical equipment. Unlike Part A, Part B has a monthly premium that everyone pays, and the late-enrollment penalty is the one that bites: 10% of the standard premium, permanent, for every full 12-month period you were eligible but didn't enroll. The premium also carries IRMAA surcharges if your MAGI from two years ago exceeds the income thresholds.; See also:Medicare Enrollment Deadlines Medicare Deadlines Irmaa
Medicare Part D: Prescription drug coverage — sold by private insurers under Medicare guidelines.; Medicare Part D is prescription drug coverage offered by private insurers under Medicare's regulatory framework. Part D has its own late-enrollment penalty separate from Part B: 1% of the national base beneficiary premium for every full month without "creditable" drug coverage after you were first eligible. Like Part B, the penalty is permanent. Active employer plans, TRICARE, and VA benefits typically count as creditable; ACA Marketplace plans usually do not.; See also:Medicare Enrollment Deadlines Medicare Deadlines Irmaa
Medigap (Medicare Supplement): Standardized private insurance plans (Plan A through Plan N) that pay some or all of original Medicare's out-of-pocket costs.; Medigap is the umbrella term for Medicare Supplement Insurance — standardized private plans (lettered A through N) that pay some or all of the cost-sharing amounts (deductibles, coinsurance, copays) that original Medicare leaves to the beneficiary. Medigap policies pair with original Medicare (Part A + Part B), not with Medicare Advantage. Critically, the one-time guaranteed-issue underwriting window during the six months after Part B starts is the only period most beneficiaries can buy Medigap without medical underwriting. Miss it, and a future Medigap purchase may be denied or priced punitively based on health status.
Modified Adjusted Gross Income (MAGI): Adjusted Gross Income plus a small set of add-backs — different definitions for different purposes (IRMAA MAGI, ACA MAGI, Roth MAGI).; Modified Adjusted Gross Income is your IRS Adjusted Gross Income plus a small set of add-backs that vary by purpose. **IRMAA MAGI** = AGI + tax-exempt interest + certain foreign-earned income exclusions; this is what determines Medicare premium surcharges two years later. **ACA MAGI** adds back tax-exempt Social Security benefits and is used for premium tax credits before age 65. **Roth contribution MAGI** has its own formula. Always check which MAGI definition applies to the decision you're modeling — they differ by tens of thousands of dollars in some cases.; See also:Irmaa Brackets 2026 Irmaa Roth Basics
Primary Insurance Amount (PIA): The Social Security retirement benefit you'd receive if you claimed exactly at Full Retirement Age, calculated from your 35 highest-earning years.; Your Primary Insurance Amount is the Social Security retirement benefit you'd receive if you claimed exactly at Full Retirement Age. It's calculated from your top 35 years of inflation-adjusted covered earnings, with a progressive bend-point formula that replaces a higher percentage of low earnings than high earnings. Every claiming-age adjustment — early-claim reductions, Delayed Retirement Credits — is expressed as a percentage of PIA, so PIA is the benchmark against which "claim early or delay" decisions are calculated.; See also:Social Security Claiming Ages Social Security Claiming
Required Minimum Distribution (RMD): The minimum amount you must withdraw each year from pretax retirement accounts starting at age 73 (under current law).; Required Minimum Distributions are the IRS-mandated withdrawals from pretax retirement accounts (Traditional IRAs, 401(k)s, 403(b)s, etc.) that begin at age 73 under SECURE 2.0 (and rise to 75 for those born in 1960 or later under current law). The RMD amount is calculated by dividing the account balance on December 31 of the prior year by an IRS life-expectancy factor. RMDs are taxed as ordinary income and counted in MAGI for both IRMAA and Social Security taxability — which is why deferring withdrawals into the RMD years often increases lifetime tax cost relative to a Roth-conversion strategy in the gap years.; See also:Roth Conversion Basics Roth Basics
Roth Conversion: A taxable transfer of money from a pretax retirement account to a Roth IRA — taxed at your marginal rate this year, tax-free withdrawals forever after.; A Roth conversion is a taxable transfer of money from a Traditional IRA or other pretax account to a Roth IRA. The converted amount is added to your taxable income for the year and taxed at your ordinary marginal rate. In exchange, the money grows tax-free going forward and qualified withdrawals are tax-free. Conversions have no income limit and no dollar limit, so they're the workhorse of tax-aware retirement planning during the low-income gap years between retirement and either Social Security claiming or RMDs. Watch IRMAA and tax-bracket cliffs when sizing.; See also:Roth Conversion Basics Roth Basics
Roth IRA: A retirement account funded with after-tax dollars; qualified withdrawals (earnings + principal) are tax-free for life.; A Roth IRA is a retirement account funded with after-tax contributions or with conversions from pretax accounts. The money grows tax-free inside the account, and qualified withdrawals — both contributed principal and earnings — are tax-free for life. Direct contributions phase out above income thresholds, but conversions have no income limit. Roth IRAs have no required minimum distributions during the original owner's life, which makes them disproportionately valuable as estate- planning vehicles.; See also:Roth Conversion Basics Roth Basics
Special Enrollment Period (SEP): An 8-month window after qualifying employer coverage ends, allowing penalty-free Part B enrollment past 65.; The Special Enrollment Period is an eight-month window that opens when qualifying employer health coverage ends after age 65. During the SEP, you can enroll in Part B without the late-enrollment penalty even if you missed your Initial Enrollment Period. The SEP starts the month after employment ends or coverage ends (whichever comes first). Miss the SEP and you fall back to the General Enrollment Period — and the penalty clock is already running.; See also:Medicare Enrollment Deadlines Medicare Deadlines
Traditional IRA: A retirement account funded with (typically deductible) pretax dollars; withdrawals are taxed as ordinary income, RMDs apply starting at 73.; A Traditional IRA is a retirement account funded with deductible pretax dollars (subject to income limits if the contributor or spouse has a workplace plan). Money grows tax-deferred inside the account; withdrawals in retirement are taxed as ordinary income. Required Minimum Distributions begin at age 73 (under SECURE 2.0; 75 for cohorts born 1960 or later under current law). Traditional IRAs are the most common source of money for Roth conversions during the gap-year window.; See also:Roth Conversion Basics Roth Basics