Invest Tools — twenty-seven calculators for investing and trading

Twenty-seven calculators for what money does over time

What a sum grows to and what a future sum is worth today, what a stream of deposits comes to and at what rate, how much of a return inflation took, and what compounding four times a year is actually worth over compounding once. Then the shares: what a dividend yields on the price and on what was paid for it, what a sale nets after both fees and the tax rate you set, and what averaging down does to the price and to the stake.

Before a trade: how large a position a fixed risk allows, what the reward is against it and how often that has to win, what a pip is worth and what the margin is — which is not the same as what can be lost. Across a portfolio: what is drifting from its weights, what a new deposit fixes without a single sale, what a fee of a fraction of a per cent takes over thirty years, and what buying the same amount every month actually paid.

Afterwards: the two ratios that disagree on purpose about whether a good month is risk, the deepest fall in a record and the gain it takes to undo it, what a bond costs at a yield and yields at a price. Nothing here fetches a quote, nothing knows your tax rules, and every rate of return you type is an assumption rather than a forecast — each tool says so on its own result.

Money and time

Compound annual growth
The one rate that makes two investments over different spans comparable

Future value
What a sum and a stream of deposits grow to, and what that is in today's money

Present value
What money in the future is worth now, and how much of it the discount takes

Annuity
A regular payment from either end: what it comes to, and what a pot would pay

Compounding frequency
What compounding more often is actually worth, which is less than everybody expects

Real rate of return
What is left of a return after fees, tax and inflation, in that order

Dividend yield
The yield, and the payout ratio that says whether it survives

Dividend reinvestment
What reinvesting does over decades, and how the yield on cost climbs

Stock profit
What a trade made once both fees and the tax are in it

Average purchase price
The weighted average after several buys, and the move needed to get back

Break-even price
The price at which a position has covered everything it cost

Trading

Position size
How much to put on, decided by the stop rather than by the conviction

Risk and reward
The ratio, and the win rate the plan needs before it makes money

Pip value and margin
What one pip is worth, what the position needs behind it, and the two decimal places that differ

Option payoff
The shape of a position at expiry, with its break-evens marked

Portfolio

Portfolio allocation
The gap between the weights wanted and the weights held, and the trades that close it

Rebalancing by deposit
A new deposit split so that nothing has to be sold — no fee and no taxable event

Fund fee impact
What a percentage point takes over thirty years, which is about a third of the pot

Regular investing
Buying at a series of prices against buying once, and the average each paid

Measuring a record

Sharpe and Sortino ratio
Return against risk, twice — because one of them counts a good month as risk

Maximum drawdown
The deepest fall from a peak, how long it lasted, and the gain that undoes it

Bond price and yield
Price from yield, yield from price, and the duration that says how far it moves

Tokens

Crypto profit
What a token trade made once both exchange fees are in it

Impermanent loss
What providing liquidity costs against simply holding, and why the name is wrong

Staking rewards
What staking pays after the validator's cut, which is not the advertised rate

Decisions

Capital gains tax
The gain, the allowance, the losses and what is left to be taxed — with every rule yours

Pay off a loan or invest
Both paths costed, and the sentence that decides it: one of the two is certain

Questions

Why is my annual return not the total return divided by the years?: Because growth compounds. A hundred that becomes two hundred over ten years did not grow ten per cent a year — it grew 7.18 per cent a year, and dividing the total by the years overstates it by nearly half. The compound annual growth rate is the constant rate that would have produced the same ending value, and it is the number worth comparing one investment against another with.
Why does a fee of one per cent take a quarter of the money?: Because it is charged every year on a balance that is growing, and the money it takes is money that does not compound afterwards. Over thirty years the difference between 0.2 and 1.2 per cent a year is not one per cent of the ending value; on the numbers the fee tool starts with it is a third of it. The tool shows both totals side by side.
Which is right, the Sharpe ratio or the Sortino ratio?: They answer different questions, and the tool shows both for that reason. The Sharpe ratio measures return against the spread of returns, counting an unusually good month as risk exactly as it counts a bad one. The Sortino ratio counts only the months below the target. On a record with a few large gains they disagree, and that disagreement is the information.
Is anything I type uploaded?: No. The tools are compiled to WebAssembly and run inside the browser tab. Nothing you type is sent to a server, and you can watch your browser's network panel while you use one to see that nothing leaves the page. That is worth more here than elsewhere: these are holdings, positions and what they are worth.

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