How to check what your cash is actually earning

A savings account that grows from €10,000 to €10,518 hasn't necessarily earned €518. If you added €1,000 and withdrew €500, most of that growth came from your own money. The remaining €18 still needs checking for interest, fees, and other entries.

There is a timely reason to review those details. The ECB's July 2026 bank-rate release, published September 2, reported 0.28% for household overnight deposits and 2.14% for new agreed-maturity deposits. These are weighted aggregates for different products and statistical bases. They aren't offers you can necessarily obtain, or a reason to lock away money you need soon.

The useful question is narrower: what did this account earn, what did keeping it cost, and can you reach the money when needed?

What information do you need from each savings account?

Write down the account's purpose and terms before comparing its rate. Cash for next month's bills has a different job from cash reserved for a later purchase.

• Starting and ending balances for the same statement period.
• Deposits, withdrawals, interest entries, fees, bonuses, and any tax withheld.
• The rate definition, effective dates, balance tiers, and bonus expiry.
• How interest accrues, when it is credited, and whether it stays in this account.
• Withdrawal restrictions, notice periods, maturity, and early-access penalties.

Use the account's own currency for the first calculation. Exchange-rate changes can alter the value shown in your home currency without changing the interest the bank paid.

A personal balance sheet helps separate accessible cash from assets that take longer to reach. Keep that distinction when judging a rate.

How do you reconcile credited interest with balance growth?

Start with statement entries, then check that they explain the ending balance. A residual difference is something to investigate; it is not automatically gross interest.

This fictional account has no tax withholding, bonuses, currency conversion, or interest paid elsewhere. Its statement shows €20 of gross interest and a €2 fee.

Ending balance = starting balance + deposits − withdrawals + credited interest − fees, under the assumptions above.

If the bank pays interest into another account, follow that payment separately. If it withholds tax or applies an adjustment, add those entries to the reconciliation. Check the statement's definition of interest earned versus interest credited: accrued interest may not have been paid yet.

How can you estimate interest when the balance changes?

Split the period whenever the interest-bearing balance or rate changes. Calculate each part under the account's rules and add the results.

For a simple example, assume a 3% nominal annual rate, an actual/365 day count, and interest credited only at period end. There are no fees or taxes. The first 15 days have a €10,000 balance; a deposit raises it to €12,000 for the next 15 days.

Applying the rate to €12,000 for all 30 days would produce about €29.59. That overstates earnings because €2,000 wasn't present during the first half.

This is illustrative arithmetic, not a universal bank calculation. Value dates, rate tiers, leap-year conventions, rounding, and compounding can change the result. Use the bank's interest breakdown to resolve a difference. Don't divide one month's interest by the closing balance and describe the result as an annual yield.

What is the difference between a nominal rate and an effective yield?

A nominal annual rate needs a compounding convention to tell you the annual result. An effective annual yield expresses the result after the stated compounding assumptions.

For example, a fictional 3.6% nominal rate compounded monthly gives an effective annual yield of about 3.66%. The calculation is (1 + 0.036 ÷ 12)¹² − 1. It assumes the rate stays unchanged and interest remains invested, with no fees or taxes.

Labels vary by country. Ireland's CCPC explains AER as an annual savings comparison that accounts for compounding. Banco de España's English savings APR explanation uses APR for Spain's TAE, including compounding and charges. Read the local definition before comparing the letters.

APY is another effective-yield label. The US CFPB's APY rules distinguish advertised yield assumptions from the yield earned during a statement period. Those are US disclosure rules, not a rulebook for every European account.

An annualised figure doesn't mean you receive that percentage every month. Nor does it promise that a variable rate will remain available for a year.

How do you compare the useful return from two accounts?

Compare the same amount over the same holding period, with access conditions you can actually meet. Then account for costs and conditions the headline rate leaves unresolved.

1. Choose the amount and date when you expect to need it.
2. Check which balance earns the stated rate, including caps and introductory periods.
3. Estimate interest using the provider's calculation method.
4. Deduct applicable fees or early-withdrawal costs, and identify any tax treatment still to check.
5. Confirm access, provider eligibility, currency, and applicable deposit protection.

Protection belongs to the legal product and institution. The Central Bank of Ireland's digital-provider guidance distinguishes bank deposits from money held by payment or e-money providers. Check the named institution and relevant national scheme rather than assuming every cash balance has the same protection.

If cash is earmarked for a purchase, give the date as much attention as the rate. The guide to keeping savings goals visible can help connect the account with its purpose.

How can you keep the review visible in Nethaven?

Use portfolio tracking to keep an interest account alongside your other assets. Supported interest-account details include institution, APR/APY fields, maturity, and contribution records. Enter rates according to the provider's definitions.

The native interest-account detail view shows current value minus recorded net contributions as interest earned. That calculation depends on complete records. Fees, paid-out interest, or balance adjustments can make it differ from gross interest on a bank statement. Reconcile those differences before using the number as a return measure.

Recording a deposit or withdrawal does not move money at your bank. Keep the bank statement as the reference for what actually happened. Use the savings-goal guide to record the purpose separately, and compare interest with changes in your household costs without confusing the two measurements.

Save one review note per account: credited interest, net costs, access date, and next rate review. Revisit it when a bonus expires, the rate changes, or the goal date moves.

Sources checked September 7, 2026. ECB figures describe July 2026. All account balances, rates used in calculations, and earnings examples are fictional.