Fixed or variable? Compare side by side with a full amortization schedule. See how rate changes affect your monthly payment.
A fixed-rate loan keeps the same interest rate — and therefore the same payment — for the entire term. A variable-rate (or adjustable-rate) loan starts with a rate that is usually lower than the fixed option, but it can rise or fall over time as a benchmark rate changes. The choice comes down to how long you plan to hold the loan, where interest rates are headed, and how much payment uncertainty you can tolerate.
| Feature | Fixed Rate | Variable Rate |
|---|---|---|
| Initial rate | Usually higher | Usually lower (introductory discount) |
| Monthly payment | Stays the same for the whole term | Can change at each adjustment period |
| Predictability | High — you always know your payment | Low — payments can increase |
| Interest rate risk | Lender bears it | Borrower bears it |
| Best when | Rates are low or rising; you value certainty | Rates are high or falling; you will sell/refinance early |
| Typical products | Most mortgages, personal loans, auto loans | ARMs, HELOCs, some student loans, credit cards |
| Risk if rates spike | None — your rate is locked | Payments can become unaffordable |
Choose a fixed rate when interest rates are historically low or you expect them to rise, when you plan to keep the loan for its full term, or when a stable payment is important for your budget. Choose a variable rate when rates are high and expected to fall, when the introductory discount is large, or when you are confident you will sell or refinance before the rate adjusts. As a rule of thumb, only take a variable rate if you could still afford the payment at its maximum cap.
Amortization is the process of spreading out a loan into fixed payments over time. Early in the loan term, a larger portion of each payment goes toward interest rather than principal. This table shows how the split changes over the life of a $30,000 loan at 6% APR over 5 years.
| Year | Annual Payment | Paid to Interest | Paid to Principal | Remaining Balance | Interest % of Payment |
|---|---|---|---|---|---|
| Year 1 | $6,960 | $1,740 | $5,220 | $24,780 | 25% |
| Year 2 | $6,960 | $1,430 | $5,530 | $19,250 | 20.5% |
| Year 3 | $6,960 | $1,100 | $5,860 | $13,390 | 15.8% |
| Year 4 | $6,960 | $750 | $6,210 | $7,180 | 10.8% |
| Year 5 | $6,960 | $380 | $6,580 | $0 | 5.5% |
In the first year of this loan, 25% of your payment goes to interest. By the final year, only 5.5% does. This front-loaded interest structure is why making extra principal payments early in the loan saves the most in total interest. An extra $50/month in Year 1 saves more than $100/month in Year 4. Use this loan calculator to see your personalized amortization schedule.
Lenders compute your payment from a single amortization formula. Walking through it once by hand makes it obvious why early payments are mostly interest — and why extra principal payments hit so hard:
The reason an early-payment-heavy interest split hurts: at month one only $358 of your $483 built equity, but by month 55 it is over $470. This is also why one extra principal payment in year one saves far more interest than the same payment in year four — it removes balance that would otherwise have compounded for the entire remaining term.
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