i What this calculator does
The time machine takes an amount, an asset and a start year and shows what the position would be worth at the end of the latest year in the data, in rand or in dollars, together with the multiple and the compound annual growth rate. The series are year-end closing values for Bitcoin, gold, the S&P 500, the JSE All Share and the dollar-rand rate.
It is a price-return tool: dividends on the indices and interest on cash are not included, and it uses one value per year, so the result for a year you pick is the value on 31 December of that year. Use it to put a number on the hindsight everyone has about Bitcoin or gold, and then read the limitations before drawing a lesson from it.
This calculator is for educational purposes only. Results are estimates and may vary depending on market conditions, spreads, commissions, platform settings, and exchange rates. It should not be considered financial advice.
How to use it
Choose the amount, whether you are thinking in rand or in dollars, the asset, and the two year-ends. The result is the value of the position on 31 December of the end year. For dollar assets held by a rand investor, the position is converted at the year-end dollar-rand rate at both ends, so the rand weakness of the period is included in the rand result. The chart shows the value at every year-end in between, which is where the real lesson usually sits: the path, not the endpoint.
What the data is and is not
The series are year-end closing values from the sources listed in the data file: CoinMarketCap for Bitcoin, the LBMA afternoon price for gold, S&P Dow Jones Indices and the JSE for the two indices, and the SARB reference rate for the dollar. The two indices are price indices, so dividends, which added roughly 2% a year to the S&P 500 and 3% to 4% a year to the JSE over this period, are not in the result. Nothing is deducted for brokerage, custody, spreads or tax. Bitcoin before 2013 is left out because there was no liquid market at scale.
Why this is not a forecast
Picking a start year after the fact is the purest form of hindsight: you already know which years were good. The same series shows Bitcoin losing 73% in 2018 and 64% in 2022, gold spending eight years below its 2012 level, and the JSE going nowhere in dollar terms for most of the 2010s. Use the table to find the worst stretch inside your window before you decide what the multiple means. For a position you could actually have held, the rand cost averaging calculator models buying a fixed amount every month instead of one lump sum.
Spotted an outdated figure? If a rate, limit or formula in this calculator no longer matches its source, email us the page and the source. A material correction is dated on the Updates Log.
Frequently asked questions
Why does the rand result differ so much from the dollar result?
Because the rand lost roughly half its dollar value between 2013 and 2024. A dollar asset held by a rand investor gains that currency move on top of the asset return, which is why gold looks far better in rand than in dollars over the same window.
Are dividends included?
No. The S&P 500 and JSE All Share series are price indices. A total-return version would be higher by about 2% a year for the S&P 500 and 3% to 4% a year for the JSE over this period.
Why does the data stop at a year-end instead of today?
One value per year keeps the series small enough to embed and verifiable against a single published close. The series is extended every January; the end date shown in the breakdown is the last year available.
Can I use it for a monthly investment instead of a lump sum?
Not here. The rand cost averaging calculator does that, and the two together are a useful comparison: the lump-sum result depends almost entirely on the entry year, the monthly result far less so.
Why is Bitcoin only available from 2013?
Before 2013 the market was too small and too thinly traded for a year-end close to mean much, and the exchanges that published prices then no longer exist.
Does a big multiple mean I should buy that asset now?
No. It means that one particular start date was favourable. The same tool with a start of 2017 for Bitcoin or 2012 for gold shows years of losses before any gain, which is what holding the position would actually have felt like.
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