CDs vs high-yield savings vs money market accounts

What is the difference, in one paragraph?

A CD locks a fixed rate for a fixed term and penalizes early withdrawal. A high-yield savings account pays a variable rate with no lock-up. A money market account is a variable-rate deposit account that adds check-writing or a debit card. All three are bank deposits, and at an FDIC-insured bank all three carry the same insurance: $250,000 per depositor, per insured bank, per ownership category. You are not choosing between different levels of safety. You are choosing where to sit on the trade-off between rate certainty and access.

What is a certificate of deposit?

A CD is a deposit you agree not to touch for a stated term, in exchange for a rate the bank fixes for that whole term. Terms typically run from three months to five years. When the CD matures you get principal plus interest, and you usually have a short grace period — commonly seven to ten days — to withdraw before the bank automatically renews it into a new term. Missing that window is one of the most common and most avoidable savings mistakes; set a calendar reminder the day you open it.

The thing you are actually buying is certainty. Whatever the market does, the rate on the paper does not move.

How do early-withdrawal penalties work?

A penalty is almost always expressed as a fixed number of months of interest on the amount you pull out, disclosed before you open the account. Shorter terms carry smaller penalties, longer terms carry larger ones. The arithmetic is simple:

• Penalty ≈ (annual interest on the withdrawn amount ÷ 12) × the number of penalty months.
• So a six-month-of-interest penalty costs roughly half a year’s earningson that money, and a twelve-month penalty costs roughly a full year’s.

Two details people miss:

• The penalty can eat principal.If you break a five-year CD three months in and the penalty is worth a year of interest, the CD has not earned that much yet — so the shortfall comes out of your deposit. Federal rules also require a minimum penalty of seven days’ simple interest if you withdraw within the first six days after the deposit.
• Partial withdrawals may not be allowed at all. Many CDs are all-or-nothing: to get at any of it, you close the whole thing.

What is rate-lock risk?

A fixed rate cuts both ways, and most people only think about one direction.

• Rates fall → the CD wins. Your locked rate keeps paying while savings accounts reprice downward within days. This is the scenario CDs exist for.
• Rates rise → the CD traps you.Your money is stuck at yesterday’s rate while new accounts pay more, and the only exit is a penalty. The longer the term, the bigger the trap.

High-yield savings and money market accounts have the mirror-image profile: they follow rates up quickly, and they follow rates down just as quickly. Their rate is variable and can change any day, without notice. A rate you saw when you opened the account is not a commitment.

What is a high-yield savings account?

A high-yield savings account is an ordinary savings account that pays a competitive variable rate, usually because the bank runs online and passes branch savings through to depositors. Money is available on demand, typically by transfer to a linked checking account, which can take a business day or two to land. There is no lock-up and no penalty.

The old federal six-transfer-per-month cap on savings accounts was suspended in 2020, but individual banks may still impose their own limits or fees, so read the schedule. Our high-yield savings guide covers what to check before moving an emergency fund.

What is a money market account?

A money market deposit account is a variable-rate savings product with checking-style access — often a debit card, check-writing, or both. Functionally it is a high-yield savings account with more payment convenience, sometimes in exchange for a higher minimum balance or a tiered rate that only pays well above a threshold.

Money market account vs money market fund — why this matters

A money market account at a bank is FDIC-insured. A money market fund at a brokerage is not. This is the single most important distinction on this page, and the names are close enough that people conflate them constantly.

• Money market deposit account (MMDA) — a bank deposit. Covered by FDIC insurance up to the standard limits. Principal does not fluctuate.
• Money market fund (MMF) — an SEC-registered mutual fund that holds short-term debt. Held at a brokerage, not FDIC-insured, and it can lose value. In 2008 one large fund “broke the buck,” falling below the $1.00 share price investors assumed was fixed.

Money market funds are not inherently bad — they are a widely used cash vehicle. But they are an investment, not a deposit, and if insurance is the reason you feel comfortable, you need the account and not the fund. Check what any given institution actually holds your cash in before you assume coverage, and use our FDIC insurance calculator to see how much of your deposit balance is protected.

How does a CD ladder work?

A ladder splits one lump sum across several CDs with staggered maturities, so part of the money comes free on a regular schedule instead of all of it being locked to one date.It removes the “what if rates move right after I commit” problem without forcing you to guess.

Worked example: $50,000 in five rungs. Split it into five $10,000 CDs at one, two, three, four, and five-year terms.

• End of year 1: the 1-year matures. Roll that $10,000 into a new 5-year CD.
• End of year 2: the original 2-year matures. Roll it into a new 5-year.
• End of year 3: the original 3-year matures. Roll it into a new 5-year.
• End of year 4: the original 4-year matures. Roll it into a new 5-year.
• End of year 5: the original 5-year matures. Roll it into a new 5-year.

From year five onward the ladder is at steady state: all $50,000 is earning five-year rates, and $10,000 becomes available every twelve months with no penalty. You have converted a single all-or-nothing timing bet into five smaller ones spread across the rate cycle.

Variations worth knowing: a short ladder (three, six, nine, twelve months) does the same thing for money you may need within a year. A barbell puts money only at the very short and very long ends, skipping the middle.

What are no-penalty and bump-up CDs?

They are CDs that give back some of the rigidity, and you usually pay for that flexibility with a lower rate.

• No-penalty CD(sometimes “liquid CD”): you can withdraw after a short initial lock-in, typically about a week after funding, with no penalty. It behaves like a savings account whose rate cannot be cut. Usually all-or-nothing on the withdrawal.
• Bump-up CD: you get the right to raise your rate to the bank’s then-current rate for that term, usually once, sometimes twice over the term. It is insurance against being locked in while rates climb.
• Add-on CD: lets you make additional deposits into an existing CD at the original rate, which is valuable when rates are falling.
• Callable CD: the bank can end it early, typically when rates drop. Read this one carefully — the option belongs to the bank, not to you.

APY vs APR: what am I actually comparing?

APY includes compounding; a plain annual rate does not. Interest paid monthly starts earning interest itself, so the effective yield exceeds the nominal rate.

The formula is APY = (1 + r/n)^n − 1, where r is the nominal annual rate and n is compounding periods per year. Using 5% purely as arithmetic, not as a quoted rate: a nominal 5% compounded monthly gives (1 + 0.05/12)¹²− 1 = about 5.12% APY. Compounded daily it is a shade higher still.

The Truth in Savings Act requires US banks to disclose deposit yields as APY, precisely so two products are comparable on one number. APR is the mirror concept on the borrowing side — the cost of credit including certain fees — and you should be suspicious of any savings pitch that quotes APR instead of APY. When comparing, also check the balance tier the advertised yield applies to, and whether it is a promotional rate that reverts later.

Which one should I use? A decision table by time horizon

A few rules that apply to all three

• Confirm the institution is insured first. The rate is irrelevant if the coverage is not there. Look up any institution in our bank directory to check its FDIC status.
• Insurance limits are per bank, not per account. Opening a CD and a savings account at the same bank in the same ownership category does not double your coverage. Spreading across institutions or ownership categories does.
• Read the fee schedule, not the headline. Monthly maintenance fees, minimum-balance requirements, and tiered rates can undo a yield advantage entirely.
• Deposit interest is taxable. Interest is generally reported to you and to the IRS on Form 1099-INT, including CD interest credited but not withdrawn.

When you are ready to compare specific products, start on our savings rates page. We deliberately do not print fixed rates in guides — they change constantly, and a stale number is worse than no number.