Term deposit or savings account: the after-tax maths

Comparing the rate on a term deposit with the rate on a savings account is like comparing a price with VAT to a price without. Interest on a Belgian term deposit (compte à terme) carries 30% withholding tax from the first euro. That tax is called précompte mobilier in Belgium. Interest on a compte d'épargne réglementé, a regulated savings account, is exempt up to €1,020 per person in 2026. The difference in treatment weighs more than the difference in rates.

A term deposit needs 1.43 times the rate to break even

The calculation is a single division. A term deposit leaves you 70% of its interest. A regulated savings account leaves you 100%, as long as you stay under the exemption ceiling. To match a regulated account, a term deposit therefore has to advertise 1 / 0.70 of the rate, or 1.43 times more.

Wikifin, the website of the FSMA, Belgium's Financial Services and Markets Authority, states it plainly: the exemption and the reduced 15% rate are reserved for regulated savings accounts. On a term deposit the withholding tax is 30%, with no threshold and no allowance.

Let us apply the coefficient to the savings accounts on the Belgian market.

The best Belgian term deposit recorded on 25 September 2026 advertises 3.58% gross, over six months. None comes close to the 4.29% on the fifth line. Against a boosted savings account, the contest is over before it starts.

One line changes everything: Keytrade, at 1.90%. There the threshold drops to 2.71% gross, and several term deposits move ahead.

How does a term deposit work in Belgium?

You deposit a sum for a period fixed in advance, from one month to ten years, at a rate guaranteed for the whole term. At maturity the bank returns the capital and the interest. On durations longer than a year, interest is usually paid out annually.

The minimum amount ranges from zero at Beobank to €25,000 at Nagelmackers, according to the sheets recorded by Guide-Epargne, which listed 141 Belgian term deposits on 24 September 2026. MeDirect caps its offer at €100,000 per client.

The money is locked. Early exit requires the bank's agreement and a contractual break penalty, when it is allowed at all.

What does €20,000 return over twelve months, after tax?

Between €350 and €448 depending on the formula, and the ranking does not follow the gross rates. Here is the full calculation, with rates recorded on 25 September 2026.

Term deposits: net rates published by Test-Achats on 6 July 2026 and 13 August 2026, gross rates reconstructed by dividing by 0.70. Keytrade: key information sheet dated 24 March 2026.

The MeDirect term deposit wins, by €68. For that gap you accept not touching €20,000 for a year, on an offer the bank itself describes as temporary. The Keytrade account, by contrast, is still there the next morning.

Look at the third line. A regulated savings account whose gross rate is almost a quarter lower than the Argenta term deposit still collects €30 more over the year, stays accessible without notice, and exposes its holder to no penalty if they change their mind after two months. Tax alone is enough to overturn a rate gap of that size.

A savings account at 1.90% beats a term deposit at 2.50%. Nothing but the withholding tax explains it.

Which term deposit duration pays best?

Test-Achats, the Belgian consumer organisation, recorded the net returns of fourteen institutions on 6 July 2026. Three durations, and a hierarchy that does not reward patience.

MeDirect: rates recorded by Test-Achats on 13 August 2026, temporary offer. Other durations: Test-Achats, 6 July 2026.

Over three years, eight banks sit within a hair of each other between 1.75% and 1.82% net: Beobank, Crelan, vdk bank, Argenta, Izola, Europabank, MeDirect and Santander. The bottom of the table is far more interesting. Nagelmackers offers 0.11% net over eight years with a €25,000 minimum, which works out at €27.50 a year for eight years of immobilisation.

Why do eight years locked away pay less than twelve months?

Because the Belgian yield curve is flat, and banks no longer need to pay for duration. Beobank pays 2.14% net over eight years. MeDirect pays 2.24% over twelve months.

On €20,000, the gap is €20 a year, so €160 handed over for the privilege of being tied down.

The counter-argument is serious: a fixed rate over eight years protects you from a general fall in rates, where a savings account can see its base rate cut overnight. That is the one good reason to sign long. The long rate would still have to be paid.

Above €53,700, the ranking reverses

The €1,020 exemption is a fixed amount, not a percentage. The larger the capital, the more the tax advantage of the regulated savings account dilutes.

On a regulated account paying 1.90% with no monthly deposit cap, the ceiling is reached at around €53,700 of deposit. Beyond that, the share of interest above the exemption carries 15% withholding tax, and the effective return on the account starts falling.

Take the same two formulas again, this time on €100,000, the deposit guarantee ceiling per bank per person.

• Keytrade High Fidelity: €1,900 of gross interest, of which €1,020 exempt and €880 taxed at 15%, so €132 of tax. Net: €1,768, effective return 1.77%.
• MeDirect term deposit, 12 months: €3,200 gross, €960 of withholding tax. Net: €2,240, effective return 2.24%.

The gap widens from €68 to €472 a year. The term deposit has not changed its nature; the tax advantage on the other side has simply run out.

Four lines to read before signing

The conditions matter as much as the rate, and three of them never appear in comparison tables.

• The exact duration and maturity date, with any mention of automatic renewal. Many term deposits roll over on their own, at the rate of the day, which can be far lower.
• The early break penalty, and simply whether exit is allowed at all. Some banks refuse it on short durations.
• The competent guarantee fund. The €100,000 guarantee covers term deposits, but a Belgian branch of a foreign bank falls under its home country's fund, not the Belgian one.
• Whether the rate is temporary. MeDirect states that it reserves the right to end its offer at any time, which changes nothing for a contract already signed, but a great deal for anyone comparing today and subscribing in three weeks.

Two formulas, two distinct situations

One clarification that is not a formality: this site compares fees, rates and conditions. It recommends no investment and gives no personalised advice. The choice between availability and return depends on your situation, and on nothing else.

The monthly deposit cap deserves a last word, because it often cancels out the reasoning above. A Belfius Flow at 3.10% accepts only €600 a month, a KBC Start2Save €500. For capital already in hand, these accounts are not competitors to a term deposit: they only accept a fraction of it. On €20,000 to place, a Flow opened today will have absorbed just €7,200 a year from now, and the rest will have to wait its turn elsewhere. The 1.43 coefficient therefore applies only to the share of money the regulated account is willing to take. We covered that mechanism in why the advertised savings rate is not your yield, and the case of a savings account without a cap in our article on Keytrade Keypack.

For the full picture of the market, savings rates set against current account costs, our ranking of Belgian banks covers the data institution by institution, and the bank comparator lets you sort it. If you disagree with your bank about an interest calculation or a break penalty, Ombudsfin, the Belgian ombudsman for financial disputes, handles complaints free of charge once the bank's own complaints service has been through.

Sources

• Wikifin (FSMA), How is interest on your savings account taxed?: the €1,020 exemption reserved for regulated accounts, 15% withholding tax above it, 30% on other investment income. Accessed 25 September 2026.
• Wikifin (FSMA), What is a term deposit?: durations, capital lock-up, interest payment. Accessed 25 September 2026.
• FPS Finance, Movable income: withholding tax rates and exempt amount for the 2026 assessment year. Accessed 25 September 2026.
• Test-Achats, A fixed rate, but at what price? The real return on term deposits: 6 July 2026, net rates at 3, 5 and 8 years for fourteen Belgian institutions, minimum deposits.
• Test-Achats, MeDirect strikes hard with a term deposit at 2.24% net: 13 August 2026, 3.20% gross over twelve months, €100,000 cap.
• La Libre, MeDirect offers 2.5% on its six-month term deposit: 12 August 2026, 3.58% gross over six months, temporary nature of the offer.
• Guide-Epargne, Compare term deposits (Belgium): 141 term deposits listed, minimum deposits, last verified 24 September 2026.
• Keytrade Bank, Key information for savers, High Fidelity account: 0.40% base rate and 1.50% loyalty bonus, no maximum deposit, sheet dated 24 March 2026.
• Ombudsfin, Filing a complaint: free mediation in the event of a banking dispute. Accessed 25 September 2026.