The balance sitting in your current account is money doing nothing

The points below about idle current account balances are ordered by how much difference they make, not by how often they get repeated.

Why the balance is larger than it needs to be

People hold a cushion in their current account because they do not know exactly what is due and when, so the cushion covers the uncertainty. That uncertainty is a data problem rather than a cash requirement, and the cost of solving it with cash is the interest forgone.

The larger the cushion, the less anyone thinks about the timing, which makes the cushion self-perpetuating. The fix is a list of scheduled payments and their dates, after which the required buffer becomes a calculable number.

Calculating the buffer you actually need

Add the payments due between now and the next income date, then add a margin for the variable ones. That total, not a round number chosen for comfort, is the balance the account needs to hold. For most households the calculated figure is noticeably smaller than the habitual one, and the difference is what can be moved.

Recalculating annually keeps it accurate as bills change.

Sweeping the excess

A standing order moving a fixed amount to savings the day after income arrives is the simplest implementation. Some banks offer automatic sweeping based on a target balance, which handles variation without intervention.

Over a full year, the savings account should be instant access, since this money is a buffer rather than a long-term holding. Sweeping into an account linked to the same card defeats the purpose, because the money remains casually spendable.

What it is worth

On a small excess the annual interest is negligible and the exercise is not worth the effort. On a larger one — several months of expenses left idle for years — the forgone interest becomes a real sum, and it compounds. The calculation is simple: multiply the average excess by the difference between your current account rate and a decent savings rate.

In numbers, if the answer is small, leave it; the point is to make the decision knowingly rather than by default.

Some current accounts do pay

A minority of accounts pay competitive interest on credit balances, usually capped at a modest amount and conditional on funding requirements or direct debits. Where such an account exists and the conditions are ones you already meet, it removes the need to sweep up to the cap.

For most households, the conditions are the catch, and an account whose interest depends on behaviour you have to remember is one that will eventually fail to pay. Reward accounts with monthly fees need the fee subtracted before comparing, which frequently reverses the ranking.

Rates, thresholds and rules differ by country and change often — check current figures before acting.

Do not sweep into an overdraft

Moving too much out and dipping into an authorised overdraft costs far more than the savings interest gained, since borrowing rates exceed deposit rates by a wide margin. This is why the buffer calculation should be generous rather than minimal, and why the sweep amount should be conservative. Where income timing is irregular, a larger buffer is cheaper than repeated overdraft use.

The arithmetic is straightforward: the aim is to stop leaving several months of expenses idle, not to run the account at zero.

Everything above, in order of what to do first

1. Why the balance is larger than it needs to be. People hold a cushion in their current account because they do not know exactly what is due and when, so the cushion covers the uncertainty.
2. Calculating the buffer you actually need. Add the payments due between now and the next income date, then add a margin for the variable ones.
3. Sweeping the excess. A standing order moving a fixed amount to savings the day after income arrives is the simplest implementation.
4. What it is worth. On a small excess the annual interest is negligible and the exercise is not worth the effort.
5. Some current accounts do pay. A minority of accounts pay competitive interest on credit balances, usually capped at a modest amount and conditional on funding requirements or direct debits.
6. Do not sweep into an overdraft. Moving too much out and dipping into an authorised overdraft costs far more than the savings interest gained, since borrowing rates exceed deposit rates by a wide margin.

The takeaway

Work out what the month actually needs, sweep the rest on payday, and keep well clear of the overdraft.

The decision is rarely about picking the best option — it is about avoiding the expensive one.