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Financial Math

CD Ladder Calculator | Multi-Rung Certificate of Deposit Strategy

Build a certificate of deposit ladder with 2 to 6 rungs, each with its own APY and term. See a complete maturity schedule, rolling reinvestment projections, total interest earned per rung, and how the ladder compares against putting everything in one CD.

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Total to ladder across all CDs

Rate when rolling maturing CDs

CD Rungs (3 of 6)

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What Is the CD Ladder Calculator | Multi-Rung Certificate of Deposit Strategy?

A CD ladder staggers your money across multiple certificates of deposit with different maturity dates. As each CD matures, you reinvest it at whatever rate is current — which gives you the benefits of higher long-term rates while maintaining predictable liquidity at regular intervals. It is the primary strategy for squeezing maximum yield from FDIC-insured savings without locking all your money away for years.

  • Liquidity at regular intervals. If you build a 5-rung ladder with terms of 1–5 years, one CD matures every year. You can reinvest or access that capital without penalty.
  • Capture rising rates. If interest rates rise, your shorter-term CDs mature quickly and can be reinvested at the higher rate — unlike a single long-term CD that locks you in.
  • Reduce reinvestment risk. If rates fall, only the portion maturing at that time is reinvested at lower rates; the rest continues earning the originally locked-in higher rate.
  • FDIC protection. Up to $250,000 per depositor per institution. Spreading across institutions can increase coverage. The laddering strategy is independent of how many banks you use.

Formula

CD Maturity Value (Daily Compounding)

FV = Principal × (1 + APY / 365)^(days)

where days = (termMonths / 12) × 365

Blended APY (weighted average)

Blended APY = Σ(APY_i × Principal_i) / Total Principal

Interest Earned per Rung

Interest = Maturity Value − Principal

How to Use

  1. 1

    Enter the total amount to invest across the ladder.

  2. 2

    Choose the number of rungs (2–6) and assign a term to each.

  3. 3

    Enter the APY for each rung from current bank or brokerage quotes.

  4. 4

    Toggle off equal splitting to set custom amounts if rungs are unequal.

  5. 5

    Click Build CD Ladder to see maturity schedule and total interest earned.

  6. 6

    Compare total yield against putting everything in a single CD at blended APY.

  1. 1
    Set total investment: Enter the total amount to distribute across your CD ladder, or toggle off equal splitting to set custom amounts per rung.
  2. 2
    Choose number of rungs: Add 2–6 rungs. Classic strategies use 3–5 rungs. More rungs provide more liquidity intervals but add complexity.
  3. 3
    Set term per rung: Assign different maturity dates to each CD — e.g., 1 year, 2 years, 3 years. Shop different banks for the best APY on each term.
  4. 4
    Enter APY per rung: Each rung can have a different APY. Longer-term CDs typically (but not always) pay more. Enter the actual rate you were quoted.
  5. 5
    Set reinvestment APY: When CDs mature, this is the estimated rate for rolling them over. A conservative assumption is to use the current short-term rate.
  6. 6
    Review the maturity schedule: The timeline shows exactly when each CD matures, how much interest it earns, and the total yield versus a single CD.

Example Calculation

Example: 3-rung ladder with $30,000

CD 1: $10,000 @ 4.50% APY, 12 months → matures in 1 year

CD 2: $10,000 @ 4.80% APY, 24 months → matures in 2 years

CD 3: $10,000 @ 5.00% APY, 36 months → matures in 3 years

CD 1 interest: $10,000 × ((1 + 0.045/365)^365 − 1) = $459.07

CD 2 interest: $10,000 × ((1 + 0.048/365)^730 − 1) = $984.79

CD 3 interest: $10,000 × ((1 + 0.050/365)^1095 − 1) = $1,618.22

Total interest: $3,062 | Blended APY: 4.77%

Year 1 liquidity: $10,459 becomes available for reinvestment or use

Understanding CD Ladder | Multi-Rung Certificate of Deposit Strategy

Classic 5-Rung Ladder: The Most Common Structure

The traditional 5-rung CD ladder divides savings equally across 1-year, 2-year, 3-year, 4-year, and 5-year CDs. Each year, the shortest-term CD matures and is reinvested into a new 5-year CD at whatever rate is then available. After 5 years, every CD is a 5-year CD maturing at annual intervals — capturing long-term rates with annual liquidity.

Short-Term Ladder for Near-Term Goals

If you have a known expense in 1–2 years (down payment, tuition), a short-rung ladder across 3-month, 6-month, and 12-month CDs keeps the money working at higher rates than a savings account while giving quarterly or semi-annual access to a portion of the funds. This is the approach for money you cannot afford to lock away for years.

  • Match rungs to your spending timeline. Money needed in 6 months goes in a 6-month CD; money not needed for 3 years goes in a 3-year CD.
  • Compare brokered CDs vs bank CDs. Brokered CDs sold through brokerages (Fidelity, Schwab) often have better rates and can be sold on a secondary market before maturity — though at market value, not par.
  • Callable CDs carry issuer risk. Some CDs allow the bank to redeem them early if rates fall. Avoid callable CDs in a laddering strategy — they defeat the purpose of locking in a rate.

Frequently Asked Questions

How does a CD ladder compare to a high-yield savings account?

HYSA: fully liquid, rate changes with market. CD: locked rate, penalty for early withdrawal.

Laddering gives you the rate-lock benefit while maintaining annual (or more frequent) liquidity.

What happens if I need to withdraw before a CD matures?

Typical penalties: 90 days interest (short-term CDs), 6–12 months interest (long-term). No-penalty CDs exist at slightly lower rates.

Should I spread my CD ladder across multiple banks?

If total savings exceed $250,000, use multiple banks for full FDIC coverage. Multiple banks also let you shop the best rate at each term independently.

How should I handle the reinvestment rate assumption?

Use the current short-term CD rate as a conservative reinvestment assumption. If the ladder math works at that rate, rising rates only make it better.

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