Savings account comparison
Enter up to four savings options — your own rates, fees, and compounding — and see which earns the most over the horizon. No bank names, just the maths.
Calculator compareLogic updated April 2026
This calculator compares up to four savings accounts side by side over a chosen horizon. Each account compounds at its own frequency (daily, monthly, quarterly, annually) and incurs any monthly fees. The output shows the projected end balance for each account, a year-by-year schedule, and the dollar gap between the best and worst options.
How this is calculated
Formula
Each compounding period: balance = balance × (1 + annualRate / 100 / periodsPerYear) ; each month: balance −= monthlyFeesStep-by-step
- For each account, convert the annual rate to a periodic rate by dividing by the compounding frequency (365, 12, 4, or 1)
- Step month by month — when a compounding event falls within a month, multiply balance by (1 + periodic rate)
- Each month, deduct any monthly fees from the balance
- Continue for the comparison horizon (in years × 12 months)
- Track year-end balances for the schedule
- Compare end balances; the highest balance wins, by the gap shown in the output
- Rounding mode
- ROUND_HALF_UP
- Precision
- 20-digit internal precision (Decimal.js), rounded to 2 decimal places for display
- Logic last reviewed
Assumptions & limitations
What this calculator assumes
- Interest rate and fees are held constant for the comparison horizon
- Daily compounding uses 365 days per year (no leap-year adjustment)
- Fees are deducted at the end of each month
- No additional deposits or withdrawals beyond the initial balance
- Taxes on interest are not modelled
What this calculator doesn’t account for
- Doesn't model introductory or promotional rates that expire after a set period
- Doesn't include any account-opening bonuses
- Doesn't factor in conditions like minimum balance or transaction limits that may forfeit the headline rate
- Doesn't account for tax on interest (which can vary by jurisdiction)
- Doesn't model variable rates that change with the central bank rate
Worked example
An initial $20,000 deposit compared across three accounts over 5 years: Account A (4.5% daily compounding, $0 fees), Account B (4.7% monthly, $5/month fee), Account C (4.6% annually, $0 fees).
| Input | Value |
|---|---|
| Initial deposit | $20,000 |
| Account A | 4.5% daily / $0 fees |
| Account B | 4.7% monthly / $5/month fees |
| Account C | 4.6% annually / $0 fees |
| Horizon | 5 years |
Account A: ~$25,065. Account B: ~$24,929. Account C: ~$25,024. Best (A) beats worst (B) by ~$136.
Account A: $20,000 × (1 + 0.045/365)^(365×5) ≈ $25,065. Account B: $20,000 × (1 + 0.047/12)^(12×5) − ($5 × 60) ≈ $25,229 − $300 = $24,929. Account C: $20,000 × 1.046^5 ≈ $25,024. Account A wins despite a lower headline rate because daily compounding edges out monthly compounding at zero fees. The headline rate isn't the whole story — fees and compounding cadence both matter.
Frequently asked questions
How do I compare savings accounts fairly?
Run them all through the same balance, horizon, and assumed-no-additional-deposits scenario. The calculator handles this by simulating each account month by month with the same starting conditions. The honest comparison is the projected end balance — that already accounts for the rate, fees, and compounding cadence. Headline-rate comparisons miss fees and compounding effects that can flip the winner.
What is the effective annual rate?
The annualised rate that produces the same return as a given headline rate at a given compounding frequency. A 5% nominal rate compounded daily has an effective annual rate of about 5.13%; compounded monthly, it's about 5.12%; annually, it's exactly 5%. Effective annual rate is the apples-to-apples comparison number across accounts with different compounding frequencies.
Introductory vs ongoing rates?
Many savings products offer a high introductory rate (often 4-12 months) that drops to a much lower ongoing rate. Over a 5-year horizon, the ongoing rate dominates — a 6% intro rate falling to 2% afterward is much worse than a flat 4% account. This calculator uses a flat rate; for products with intro+ongoing pricing, use the average effective rate over your horizon as the input.
How does compounding frequency matter?
More frequent compounding produces marginally higher returns at the same headline rate. The differences are small at typical rates (about 0.1–0.2 percentage points between annual and daily compounding at 5%) but compound over long horizons. Below 1% rates, compounding frequency barely matters. Above 8% rates, daily compounding can add several percentage points of effective return over a decade.
Should I prioritise the highest rate or no fees?
Run both through the calculator with your actual balance and horizon. Fees become significant on small balances — a $5/month fee on $5,000 is 1.2% of balance per year, often eating most of any rate advantage. On larger balances ($50,000+), the rate matters more than typical monthly fees. The calculator's projected end balance is the unambiguous answer for your situation.
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