Scale-in calculator

You already hold a position and want to add at a new price, with one stop for all of it. The calculator works out how much to add so the total loss at the stop, fees included, equals your risk. Sometimes the answer is to cut instead.

Use a negative number for a short, for example -2. Enter 0 if you have no position yet.

The most you are willing to lose if the stop is hit, fees included, in your account currency.

Use the maker fee for a limit order and the taker fee for a market order. A stop usually fills as a market order.

A fixed charge per order, like 1 or 2 dollars, if your broker has one. Most crypto exchanges do not, so leave these at 0.

How many units one contract stands for. Leave it at 1 when your size is in coins or shares.

Long

Buy 1.60996 more

Position after the order
3.60996
Fees if the stop is hit
0.51

If the stop is hit the whole position loses 25.00, fees included.

How it works

The formula

If the stop is hit, you lose on the position you already hold, you lose on the part you add, and you pay fees: the entry fee on the new part and the exit fee on everything.

The calculator sets that total equal to your risk and solves for the size of the new order. When the position you hold already loses more than your risk at the stop, the answer is negative, and the page tells you how much to cut.

risk = size × (average − stop) × multiplier + added × (new entry − stop) × multiplier + exit fee on everything + entry fee on the added part + flat fees

Worked example

Adding to a long

You are long 2 units from an average of 100. Price is now 104 and you want to add, with the stop for everything at 95. You can lose 25, and fees are 0.1% each way.

The 2 units you hold lose 10 at the stop. Each unit added at 104 loses 9 more, plus fees. The calculator says buy 1.60996 more, for a position of 3.60996. At the stop that is 10 + 14.49 of price loss plus 0.51 of fees, which is 25.

FAQ

Questions

Why does it tell me to reduce?

Because the position you already hold would lose more than your risk at that stop. Say you are long 10 units from 100, price is 98 and the stop is 95. Those 10 units alone would lose 50, so to keep the loss at 25 you sell 8.12715 now and keep 1.87285.

Does it work for shorts?

Yes. Enter the current size as a negative number, for example -2, and put the stop above the new entry price. Buy and sell are swapped in the result.

What is the contract multiplier?

Some contracts stand for more than one unit of what they track, for example a contract worth 100 of the underlying. The price loss and the fees are both multiplied by this number, because a contract of 100 units is 100 times the notional. Leave it at 1 if you size in coins or shares.

What if I have no position yet?

Enter 0 as the current size. The answer is then the same as the position size calculator gives without flat fees.

Also try: Position size calculator

Sized it right? Now see if it paid.

Viktury imports your trades and shows each one in R, with fees and funding taken out.

Start free →

No card · 14 days of Edge from first trades