Lot size calculator for forex and gold
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A lot size is a risk budget divided by a stop distance. Put in your balance, the risk you have decided on, and the stop from the signal or your own plan, and the calculator solves the rest, including the pip-value conversion people skip at 3am. It rounds down to your broker's lot step, never up, so the position cannot cost more than the risk you set.
Your position size
0.08
lots on EUR/USD, rounded down to your 0.01 lot step.
Rounding always goes down, so the position never risks more than you asked for. Spreads, commission, swap, and slippage sit on top of the number above.
How the calculation works
One equation runs the whole page, and it is worth being able to do it on paper when you are away from a screen.
lots = risk amount ÷ (stop distance in pips × pip value per 1.00 lot)
A position size calculator runs the same line. The only difference is whether the answer comes out in units of the instrument or in lots, and MetaTrader wants lots.
The risk amount is your balance times your risk percentage, or a figure in money you set yourself and keep whatever the balance does. The stop distance belongs to the trade rather than to you: read it in pips, or take the gap between entry and stop and divide by the pip size. That pip size is 0.0001 on most pairs and 0.01 on anything quoted in yen.
Pip value is the input that causes the trouble, because it has to end up in the currency your account is denominated in. One pip on one lot is the pip size times the contract size, and that figure starts life in the quote currency of the pair. From there:
- The quote currency is your account currency. Nothing to convert. On EUR/USD with a dollar account, 0.0001 × 100,000 is $10 a pip on one lot.
- Your account currency is the base currency. Divide by the price. On USD/JPY, 0.01 × 100,000 is ¥1,000 a pip, and at 157.00 that is $6.37.
- Neither one matches. Multiply by the rate from the quote currency into your account currency. EUR/GBP pays out in pounds, so a dollar account converts £10 a pip at the GBP to USD rate.
EUR/USD on a dollar account
Balance $5,000, risking 1%, so $50. The stop is 60 pips away. A pip on one lot is $10, no conversion needed. 50 ÷ (60 × 10) = 0.0833 lots, which rounds down to 0.08. A stop-out costs $48, or 0.96% of the account. The $2 left over is what the lot step costs you, and it is the right direction to miss by.
USD/JPY on a dollar account
Risking $100 flat this time, with a 25-pip stop. A pip on one lot is 0.01 × 100,000 = ¥1,000, and the dollar is the base currency here, so divide by the price: ¥1,000 ÷ 157.00 = $6.37. Then 100 ÷ (25 × 6.37) = 0.628 lots, so 0.62 after the step, and a stop-out costs $98.73. Skip the conversion and use $10 a pip instead, and you get 0.40 lots: a position a third smaller than the one you decided to take.
Gold on a dollar account
Balance $20,000, risking 1%, so $200. Entry 2,400.00, stop 2,385.50, which is 14.50 of price. At the common convention of 100 ounces a lot priced in increments of 0.01, that stop is 1,450 increments and each one is worth $1.00 on a lot. 200 ÷ (1,450 × 1) = 0.1379, so 0.13 lots and a real risk of $188.50. Your broker may run 10-ounce contracts or call 0.10 a pip, which is why both numbers are editable above.
Where the number goes wrong
Three mistakes produce most of the wrong-sized positions I see, and none of them look like mistakes at the time. The trade opens, the platform accepts it, and the damage only shows up in the size of the losses.
A yen pair read at 0.0001
USD/JPY, EUR/JPY, and GBP/JPY quote to two or three decimals, and a pip is 0.01. Read a 45-pip stop at 0.0001 and it becomes 4,500 pips, which hands you a position a hundred times smaller than the one you wanted. The instrument picker above sets the pip size for you. The case to watch is a custom symbol name from your broker, where you are setting it yourself.
A pip value that never reaches your account currency
Pip value starts in the quote currency of the pair, and most calculators quietly assume you hold a dollar account. Trade GBP/USD from a euro account and the pip pays out in dollars, so it has to be multiplied by the dollar-to-euro rate before it means anything to your balance. Leaving that rate at 1.00 when it is really 0.90 moves the position by 10%, and the error repeats on every trade in that pair until you notice it.
A gold contract that is not the one you assumed
Gold has no settled convention. One lot is usually 100 ounces, some brokers offer 10-ounce contracts, and whether a pip means 0.01 or 0.10 of price varies by broker. Get either one wrong by a factor of ten and your position is ten times the size you meant to take. One test settles it in thirty seconds: open a 0.01-lot trade and watch what a one-dollar move does to the profit and loss. On a 100-ounce contract, 0.01 lots is one ounce, so a dollar of price is a dollar of P&L. Anything else, and your contract size is not what you thought.
Why a signal copier has to size every order from the stop
This arithmetic is fine once. The problem is doing it at 3am, half awake, while the price moves, several times a week. That is the case where a copier earns its keep, and also where a bad one does the most damage: a tool that mirrors the lot size in the message is copying a number that was chosen against somebody else's balance, if it was chosen at all.
TTMT ignores the lot size a signal posts. It reads the stop distance out of that specific message and solves the volume from your own setting: a fixed lot, a percentage of balance between 0.1% and 10%, or a fixed amount of money. The amount is in your account's own currency rather than dollars, so 200 means €200 on a euro account, and one setting broadcast to several accounts risks €200 on the euro one and $200 on the dollar one.
Two details matter more than the mode you pick. The first is that a trade is not one order. An entry is split into 1 to 6 layers, and the engine works out how many orders each layer holds from your lot size and your broker's minimum lot and step, up to 6 per layer and 36 in total. Each layer carries part of the volume, so the sizing has to be solved per layer rather than once for the whole trade.
The second is that it never rounds up. If the smallest lot your broker accepts would risk meaningfully more than your percentage implies, TTMT rejects the trade and tells you, instead of opening a position that costs more than you agreed to. That is the same rule the calculator above follows, for the same reason.
More on the reasoning in why we replaced lot numbers with percentage sizing, the mechanics in the position sizing documentation, and the arithmetic itself in what lot size is and why the math goes wrong at 3am.
Questions traders ask
What lot size should I use on a small account?
Whatever your stop distance allows, which on a small account is often less than your broker will accept. A 60-pip stop on EUR/USD at the 0.01 minimum lot risks about $6. On a $200 account that is 3% of the balance on one trade, so the minimum lot is already too big for a 1% rule. The calculator says so rather than rounding you up into a position you did not choose.
How do I calculate lot size for gold?
Gold is usually 100 ounces per lot and priced in increments of 0.01, which makes one increment worth $1.00 on one lot for a dollar account. Divide your risk by the stop distance in those increments: $200 of risk over a $14.50 stop, which is 1,450 increments, gives 0.1379 lots, so 0.13 after rounding down. Check your own contract specification first, because 10-ounce gold contracts exist and some brokers count a pip as 0.10 rather than 0.01.
What is the difference between lot size and position size?
Position size is the amount of the instrument you hold. Lots are the unit MetaTrader uses to express it: 1.00 lot is 100,000 units of the base currency on a forex pair, 0.10 is a mini lot, and 0.01 is a micro lot. A position size calculator and a lot size calculator solve the same equation and print the answer in different units.
Is fixed lots or a percentage of balance better?
A fixed lot keeps the position constant and lets your dollar risk swing with the stop distance. An 80-pip stop costs four times what a 20-pip stop costs at the same lot, and wide stops usually arrive in volatile conditions, so a fixed lot quietly puts the most money at risk when the market is least predictable. Sizing from risk keeps the loss steady and moves the lot instead.
Why does my broker reject the lot size I calculated?
Usually the lot step or the minimum lot. A broker with a 0.10 step will not take 0.17, and one with a 0.10 minimum cannot open 0.03 at all. Both values sit in the contract specification: in MetaTrader, right-click the symbol in Market Watch and open Specification. Margin is the other common reason, and that one is about the size of the position rather than the size of the risk.
Can a signal copier size the trade for me?
That is what TTMT does with the signals you already follow. It ignores any lot size the provider posts, reads the stop distance from that specific signal, and solves the volume from your own setting: a fixed lot, a percentage of balance, or a fixed amount of money in your account's currency. If the broker's minimum lot would risk meaningfully more than you asked for, it rejects the trade rather than rounding up into it.
Where to go next
- Telegram to MT5 covers how signals reach a MetaTrader 5 account, sized to your rules.
- Telegram to MT4 is the same path for a MetaTrader 4 account.
- The channel directory shows what the signals being sized here actually look like.
This calculator is a tool for arithmetic, not advice. It does not know your broker's contract specification, your margin requirement, or what the spread will be when your order fills. Check the numbers against your own platform before you trade them.