Two different kinds of interest rate
A CD's advertised rate is locked in for its full term the moment you open it — the rate you see today is the rate you'll earn for the entire term, regardless of what happens to broader interest rates afterward. A high-yield savings account's rate is variable and can change at any time, typically moving in response to broader interest rate conditions. Comparing the two rates as of today treats them as equivalent when they carry structurally different risk profiles.
Why the comparison depends on your rate expectation
If you expect rates broadly to decline over a CD's term, locking in today's HYSA-comparable or slightly higher CD rate becomes more attractive, since a HYSA's variable rate would likely decline alongside broader rates while the CD rate stays fixed. If you expect rates to rise, the opposite consideration applies — a flexible HYSA rate could end up earning more than a rate locked in today.
What a static day-one comparison misses
A comparison based solely on today's two rates implicitly assumes the HYSA rate will remain unchanged for the entire comparison period — an assumption that's rarely true over a CD term of 6-12+ months, given how frequently high-yield savings rates move in response to central bank rate decisions and competitive market pressure among providers.
The penalty for early CD withdrawal is a real, separate consideration
A CD's rate lock is also a liquidity tradeoff — funds are generally not accessible without penalty before the term ends, unlike a HYSA which typically allows withdrawal at any time. This flexibility difference matters independently of which option produces higher expected earnings, particularly for funds that might be needed unexpectedly before the CD term completes.
What running a rate-drift scenario adds to the decision
Modeling a specific rate-direction expectation, rather than assuming today's numbers hold static, produces a more realistic earnings comparison — while still being explicit that it's a scenario based on your own rate expectation, not a guarantee of what will actually happen to rates over the term.
Frequently Asked Questions
A CD's rate is locked for its full term the moment you open it, while a HYSA's rate is variable and can change at any time — a same-day comparison implicitly assumes the HYSA rate stays static for the entire period, which is rarely a realistic assumption over a CD term of 6-12+ months.
If you expect rates to decline over the term, locking in a CD rate today becomes more attractive since a HYSA's variable rate would likely decline too — if you expect rates to rise, a flexible HYSA rate could end up outearning a rate locked in today.
It applies a simple linear drift to the HYSA rate over the term based on your selected expectation (flat, up, or down), producing a more realistic earnings scenario than assuming today's rate holds static — clearly presented as a modeled scenario, not a guaranteed forecast.
Early CD withdrawal typically carries a penalty, unlike a HYSA which generally allows withdrawal at any time — this liquidity difference matters independently of which option produces higher expected earnings, especially for funds that might be needed unexpectedly.
No. All calculation happens locally in your browser — your savings amount and rate inputs are never uploaded or logged.