How our calculators work

Where does the data come from?

Prices, dividends and splits come from EODHD, a market data provider. We store them in our own database and refresh them once a month. History goes back to January 1990, or to the fund’s first trading day if it launched later.

Today the calculators cover US-listed ETFs and funds priced in US dollars. You can see the full list on our All ETFs page.

Why monthly prices?

We use one price per fund per month: the month’s closing price. Every transaction in a month (your initial investment, a contribution, a withdrawal or a reinvested dividend) happens at that price. Monthly data is a good fit for long-term plans built around monthly contributions, and it lets funds from different exchanges line up month by month.

The trade-off: we don’t model the exact day you would have bought. Over years of investing, that difference is small.

How are dividends and splits handled?

We start from the fund’s actual traded price, unadjusted, and then apply the real dividends and splits ourselves. For each holding, every month, in this order:

1. Splits. If the fund split its shares that month, your share count is multiplied by the split ratio, so a split never looks like a gain or a loss.
2. Dividends. Your shares × the dividend per share actually paid at the time. With dividends reinvested (the default), that cash buys more shares at the month’s price. With dividends taken as cash, it’s added to a running total and stays out of your balance.
3. Your money in or out. Then your initial investment, contribution or withdrawal for that month is applied.

Both dividend options use the same price and dividend data, so the gap between them is purely the effect of reinvesting.

When do contributions happen?

• Your initial investment is made in the first month of your date range.
• Regular contributions or withdrawals start in the second month. They follow the calendar: monthly is every month, quarterly is January, April, July and October, and annually is January.
• An annual increase (a percentage or a fixed amount) is applied every January, starting with the first January after your start month.
• A withdrawal can never take more than the holdings are worth that month. If you ask for more, you withdraw what’s left and the balance stops at zero.

How does the portfolio calculator work?

• Your money is split across holdings by the weights you set, which must add up to 100%.
• It’s buy-and-hold: we never rebalance. Holdings that grow faster become a bigger share of the portfolio over time.
• Funds launched at different times are only compared over the months they all have data for. The date range actually used is always shown with your results.
• All holdings must be priced in the same currency, since we don’t convert between currencies.

What do the results leave out?

• Taxes. No tax on dividends or gains.
• Broker costs. No trading commissions, platform fees or currency conversion fees.
• Inflation. Every figure is in nominal dollars.

The fund’s own annual fee (its expense ratio, also called TER or OCF) is already inside its historical price, because the fund takes it from its assets day by day. We don’t subtract it again.

What a backtest can’t tell you

A backtest shows how a plan would have done in the past. Past performance doesn’t guarantee future results, and a period that went well may not repeat. Use the results to understand how regular investing, time and dividends work together, and see our Disclaimer for the full terms.

We take care with the data, but we can’t check every figure against every fund’s official records. Found a mistake? Email us at contact@steadyetf.com.