Saving
In the early years the amount saved does more work than the rate earned
Returns act on a balance, so when the balance is small the return is small too — which puts the contribution in charge for longer than most people expect.
By Aditya Ramaswamy3 min read
Two levers of very unequal size
There are only two ways a pot of money grows: something gets added to it, or what is already there earns something. Those are the only levers, and almost all the attention goes to the second one — which rate, which account, which fund. That attention is misallocated at the beginning, and the reason is arithmetic rather than philosophy.
A return is a percentage of a balance. When the balance is small, a percentage of it is smaller still, and no achievable difference in rate can compensate for that. A contribution, by contrast, is an absolute amount that does not care how much is already there.
This is not an argument that rates are unimportant. It is an argument about sequence: which lever is worth working on first, and for roughly how long.
The arithmetic of a small balance
Suppose, purely as an illustration, a balance of 1,000 and a rate of 5% a year. The year produces 50. Now suppose the same person adds 100 a month, which is 1,200 over the year. The contribution has done twenty-four times as much work as the return, and it would still be doing more if the rate were doubled.
Push the rate to an implausible 10% and the return becomes 100 — still less than one month of contributions. That is the shape of the early years, and it holds regardless of what is available in your market, because the imbalance comes from the size of the balance rather than from the level of rates.
The practical consequence is that time spent hunting for a marginally better rate on a small balance is time spent optimising the smaller of two numbers. The same hour spent finding another 50 a month to contribute has a larger effect, and a certain one.
Where the two lines cross
The crossover point can be calculated exactly, and it is a genuinely useful number to know. Annual return equals annual contribution when the balance multiplied by the rate equals the amount added per year, which rearranges to: crossover balance equals annual contribution divided by the rate.
Run it on the illustration. Contributions of 1,200 a year at a rate of 5% cross over at 1,200 divided by 0.05, which is 24,000. Below that balance the contributions matter more; above it, the returns do. At a rate of 8% the crossover falls to 15,000, and at 3% it rises to 40,000.
That single formula explains a lot of otherwise confusing advice. It is why the same commentator can say contributions are what matter and, elsewhere, that returns are everything. Both are true, on different sides of a line whose position depends on how much is going in and what the money earns.
Costs deserve the attention that rate-chasing usually gets
There is one exception to the argument that percentages matter little at the start, and it works in the other direction. Charges are also a percentage, and they are deducted whether or not anything was earned. Where a rate is uncertain and variable, a cost is contractual and known in advance.
That asymmetry makes charges worth understanding early even though returns are not yet doing much. The effect of a percentage charge on a small balance is likewise small in absolute terms, but the habit of knowing what is being deducted, and the choice made at the outset, tends to persist for many years after the balance has stopped being small.
It is also the one percentage a saver can influence with certainty. Nobody can choose a return in advance. What something costs to hold is written down before the money is committed.
The relationship reverses, which is the whole point
None of this means returns are unimportant. It means their turn comes later. Past the crossover the balance is producing more each year than the household is adding, and eventually the gap becomes wide enough that contributions are a minor contributor to growth — which is the outcome the entire exercise is aimed at.
Getting there is mostly a function of the early years being consistent and boring. A high contribution rate against a small balance is what builds the balance that returns can then act on, and no rate can do that work in its absence.
What rate is realistic, what risks come attached to it and what any of this means for a particular household are questions with no general answer. Returns are not guaranteed, invested money can fall in value, and anyone making a decision of consequence should be taking it to a regulated adviser rather than to a formula.
Common questions
Does this mean the choice of account does not matter early on?
It matters less than the amount going in, which is a different claim. Making a sensible choice once and then leaving it alone is reasonable; spending months comparing options while contributing nothing is the failure this arithmetic describes. The choice becomes more consequential as the balance grows.
How do I work out my own crossover point?
Divide what you expect to contribute in a year by the rate expressed as a decimal. At 1,800 a year and 4%, that is 1,800 divided by 0.04, or 45,000. It is a rough marker rather than a threshold, since real rates vary and contributions change, but it locates the region.
Is it worth saving small amounts at all?
Yes, for a reason that is not primarily arithmetic. Small amounts build the balance that later growth acts on, and they establish the habit while the stakes are low. The absolute figures early on are always underwhelming, which is exactly why so many people stop before the interesting part.
Aditya covers spending, saving, debt and the questions readers actually send in and thinks most subjects are more interesting once you know how they work.
