An answer, not a spreadsheet
Two figures is all it asks for: what you have saved, and what you put away each month. From those it tells you in plain words how long your savings will last. "You are on track", or "your savings run out at age 79", is the first thing on the page, before any chart.
Underneath runs a single track from today to the end of your plan: the years you are still earning, the years your savings cover you, and the years they do not. Where there is a gap, the calculator says exactly what closes it, in rand a month.
Every assumption is yours to change
A projection is only as good as what it assumes, so the calculator shows its working. Five settings sit behind a disclosure: the age you retire, how long the money must last, how much of your income you will need, the return you expect after fees, and inflation. Move any of them and the answer moves with you.
Everything is worked out in today's rand, so a figure forty years out means what it sounds like rather than a large number that inflation has flattered. One tap switches to what it will say on the day, if you would rather see that.
Where MyBento does not know your salary, the figures that depend on it say so instead of filling in a guess.
What it actually costs you
Contributions to a retirement annuity are tax-deductible, so the amount leaving your pocket is smaller than the amount going into your fund. The calculator shows both: the contribution, and what it costs you once SARS has given the relief back.
That is a useful number to have before you decide. Raising a contribution from R1 900 a month to R3 251 sounds like R1 351 more. After relief it is closer to R845.
Right where you choose the amount
The same projection sits inside the retirement application, folded under the contribution step until you want it. There is one place to set the amount, and the projection follows it, so you can watch what another percentage point does to your retirement before you commit to it.
Whatever you type is kept, so coming back does not mean entering your savings again, and the figures carry into the application on the same device.
One control sets the amount; everything below it follows.