Prime Rate Savings Calculator
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Prime Rate Savings Calculator
How Rate Changes Affect What You Earn
Savings rates do not move 1:1 with prime. Banks adjust deposit rates gradually. Estimates assume a proportional APY shift equal to 60%–80% of the prime rate change.
Key Takeaways
- A $10,000 high-yield savings account at 4.50% APY currently earns about $450 per year, or $37.50 per month in interest.
- Savings rates do not move 1:1 with the prime rate. Banks typically pass through 60%–80% of each Fed rate change to deposit products, often with a delay of several weeks.
- If the Fed cuts rates by 0.50%, your HYSA yield might drop from 4.50% to about 4.15% — reducing your annual earnings by roughly $35 on a $10,000 deposit.
- CDs lock in a rate for the full term, protecting you from rate cuts. If you expect rates to decline, locking in today’s CD rate preserves your current yield.
- The “Where to Put Your Money” comparison below shows earnings across a high-yield savings account, 12-month CD, and money market account at both current and projected rates.
How to Use This Calculator
This calculator shows how prime rate changes affect what you earn on savings deposits. Unlike the borrowing calculators elsewhere in this series, here a rate increase is good news (you earn more) and a rate cut is the risk (you earn less).
Step 1 — Choose your account type. Toggle between High-Yield Savings and Certificate of Deposit. HYSA rates adjust when the Fed moves, so they are directly affected by prime rate changes. CD rates lock in at purchase, meaning the calculator shows what rate you would get if you opened a new CD after the rate change.
Step 2 — Enter your deposit amount. This is the balance in your savings account or the amount you plan to deposit into a CD.
Step 3 — Set your current APY. Check your bank’s current rate. Top high-yield savings accounts offer 4.25%–5.00% as of March 2026. CD rates vary by term but top 12-month CDs are in the 4.25%–4.75% range.
Step 4 — Select a rate scenario. Choose a prime rate change to model. The calculator estimates your new APY by applying approximately 70% of the prime rate change — this “passthrough rate” reflects how banks historically adjust deposit yields relative to the Fed’s moves.
Understanding the Results
The headline number shows the change in your annual interest earnings. For savers, the direction is flipped from borrowers: a prime rate increase means banks pay you more, while a cut means your earnings decline. The “Estimated New APY” reflects the passthrough discount — when the Fed cuts 0.25%, your HYSA typically drops by about 0.175% (70% of the cut), not the full 0.25%.
The growth timeline shows your balance trajectory month by month, including the interest earned. The bar length and color indicate whether the new rate scenario results in faster growth (green) or slower growth (gold) compared to the current rate.
The “Where to Put Your Money” comparison is the decision-making tool. It shows estimated earnings across three deposit products at both the current and projected rate. When rates are falling, CDs often show the highest return because they lock in the pre-cut rate for the full term. When rates are rising, high-yield savings accounts capture the increases more quickly since their rates adjust continuously.
Keep in mind that actual bank rate adjustments vary by institution. Online-only banks tend to adjust faster and pass through a higher percentage of rate changes than traditional brick-and-mortar banks. The 70% passthrough rate used here is a conservative national average.
Current Top Savings Rates (March 2026)
| Product | Top APY Range | Annual Earnings on $10K | Rate Adjusts With Prime? |
|---|---|---|---|
| High-Yield Savings | 4.25%–5.00% | $425–$500 | Yes — variable |
| 12-Month CD | 4.25%–4.75% | $425–$475 | No — locked at purchase |
| Money Market Account | 4.00%–4.50% | $400–$450 | Yes — variable |
| Traditional Savings | 0.01%–0.50% | $1–$50 | Rarely |
Rates reflect national top-tier offers from FDIC-insured institutions, March 2026. Individual bank rates vary.
Frequently Asked Questions
Do savings rates move exactly with the prime rate?
No. Banks adjust deposit rates based on their own funding needs and competitive positioning. Historically, high-yield savings accounts pass through about 60%–80% of each Fed rate change, often with a lag of several weeks. CD rates for new purchases adjust more promptly because they compete directly with Treasury yields.
Should I lock in a CD before rates drop?
If you believe the Fed will continue cutting rates, locking in a CD at today’s rate preserves your yield for the full term. The trade-off is liquidity — early withdrawal typically incurs a penalty of 3–6 months of interest. If you might need the money, a high-yield savings account keeps it accessible even though the rate will decline.
What is APY versus APR?
APY (annual percentage yield) reflects the total interest earned on a deposit including compounding. APR (annual percentage rate) reflects the cost of borrowing. For savings, APY is the relevant metric. A 4.50% APY means you earn $450 on a $10,000 deposit over one year, with interest compounding monthly.
How much should I keep in savings versus investing?
Financial advisors generally recommend keeping 3–6 months of essential expenses in a high-yield savings account as an emergency fund. Beyond that, long-term savings may earn higher returns in diversified investments, though with greater risk. This calculator focuses on the guaranteed-return portion of your financial plan.
Are my savings deposits insured?
Yes. Deposits at FDIC-insured banks are protected up to $250,000 per depositor, per institution. Credit union deposits are similarly insured by the NCUA. This insurance covers high-yield savings accounts, CDs, and money market accounts. Always confirm your bank’s FDIC or NCUA membership before depositing.
Why do online banks pay higher savings rates?
Online banks have lower overhead — no branches, fewer staff, lower real estate costs. They pass those savings to customers through higher deposit rates. This is why the top high-yield savings accounts consistently offer 4%+ while traditional bank savings accounts pay under 0.50%.
References & Further Reading
- FDIC — Weekly National Rates and Rate Caps
- Federal Reserve H.15 — Selected Interest Rates
- CFPB — What Is a Certificate of Deposit?
Keep Reading
- Prime Rate Impact Calculator — See the borrowing cost side of rate changes
- Prime Rate History & Forecast — 25 years of rate data
- Credit Card Interest Calculator — See how rates affect your card
- Best Personal Loans — Compare fixed-rate offers
- All PrimeRates Calculators