CD Ladder Calculator
A certificate-of-deposit ladder splits one lump sum across several CDs with staggered maturity dates, so part of your money comes due at regular intervals instead of being locked away all at once. Enter your total principal, how many rungs you want, and the APY of the shortest rung plus a step-up for each longer term, and this calculator splits the principal equally, applies each rung's rate, and shows your first-year interest and blended APY. It is an illustrative estimate, not a rate quote or financial advice.
Ladder setup
Rate model
Each rung earns base APY plus one step, so a longer term pays more: rung i = base + (i − 1) × step.
Blended APY
4.40%
across 5 rungs of $2,000.00 each
Year-1 interest
$440.00
Per rung
$2,000.00
Maturity schedule
Year-1 interest by rung
Compare scenarios
Run the same calculation with two or three input sets side by side. Differences are highlighted; every number comes from the same tested formula as the calculator above.
| Input | Scenario A | Scenario B |
|---|---|---|
| Principal | ||
| Rungs | ||
| Base Apy | ||
| Step |
How it works
The tool divides your total principal equally across the number of rungs you choose, so each rung receives principal ÷ rungs. A five-rung ladder funded with $10,000 places $2,000 in each CD. Equal splitting keeps the math transparent and mirrors the most common way ladders are built, though nothing stops you from weighting rungs differently in practice.
Each rung is assigned an APY. Using the base-plus-step model, the shortest rung earns the base APY and every longer rung adds one step: apy for rung i is baseApy + (i − 1) × step. Longer terms usually pay more, so a base of 4.0% with a 0.2% step gives rungs of 4.0, 4.2, 4.4, 4.6, and 4.8%. First-year interest for each rung is its amount × its APY ÷ 100.
Total year-one interest is the sum of every rung's interest, and the blended APY is that total divided by your principal, times 100 — the single rate that would produce the same interest if applied to the whole balance. In the $10,000 example the rungs generate $440, so the blended APY is 4.4%. The maturity table lists each rung's amount, APY, and interest so you can see exactly where the return comes from.
Frequently asked questions
Why ladder CDs instead of putting everything in one CD?+
A ladder is a trade-off between liquidity and yield. Putting the whole sum in a single long-term CD usually earns the highest advertised rate but locks every dollar away until one distant maturity, and cashing out early triggers penalties. A ladder staggers maturities so a portion becomes available at regular intervals — giving you access to cash and the chance to reinvest — at the cost of a slightly lower blended return than the longest rung alone. This calculator shows that blended APY so you can weigh the two against each other; it does not recommend a specific strategy.
Is APY the same as the interest rate?+
Not quite. The nominal interest rate is the base rate a CD pays, while APY (annual percentage yield) folds in how often that interest compounds over a year, so APY is what you actually earn and is the figure banks are required to disclose for comparison. This tool works directly in APY: each rung's first-year interest is simply amount × APY ÷ 100, which already reflects a full year of compounding. If a bank quotes you a nominal rate and a compounding frequency instead, convert it to APY before entering it here so the comparison is apples-to-apples.
Does this account for reinvestment and changing rates?+
No. The calculator is a first-year snapshot: it assumes every rung holds its stated APY for the full year and does not model what happens when a rung matures and you reinvest it at whatever rates prevail then. In a real ladder you typically roll each maturing CD into a new long-term rung, and the rate it earns depends on where interest rates sit at that future date — which nobody can know in advance. Treat the blended APY here as a starting-year estimate, and re-run the numbers with current rates each time a rung comes due.