About Sizelot
Sizelot is a set of free calculators for managing risk when trading: how many lots to open, how many futures contracts fit your risk and how much you can lose today on a prop firm account. No sign-up, no downloads, in English and Spanish.
What it calculates
- Lot size calculator: 27 forex, metals, index and crypto instruments, with the pip value, the margin and a diagram of the trade.
- Futures contracts: 12 CME Group contracts (NQ, ES, YM, RTY, GC, CL and their micros).
- Prop firm accounts: daily and maximum loss limits for 10 firms, with their rules summarized.
How it calculates
- Lots = money you risk ÷ (stop distance × contract size). The result is always rounded down to the lot step, so it never goes over your risk.
- If not even the minimum lot fits your risk, the calculator gives you that minimum lot and shows in red what you would really risk.
- Losses in another currency are converted to your account currency at the ECB reference rate. When your currency is the base of the pair (EURUSD in a euro account), the pair’s own price at the stop is used, as MT4 and MT5 do.
- Futures contracts = risk ÷ (stop in points × point value), rounded down.
- On prop firm accounts, today’s floor is the higher of the daily limit and the maximum loss; with a trailing maximum loss, the floor rises with your highest balance up to where each firm locks it.
Every calculator shows the working step by step in “How it is calculated”, so you can check it.
Where the data comes from
| Data | Source |
|---|---|
| Exchange rates | Daily reference rates of the European Central Bank |
| Contract sizes and minimum lot | Standard MT4/MT5 specifications. For 15 instruments they vary by broker: the calculator starts from Vantage’s and says what to enter for Axi. |
| Maximum leverage | ESMA limits for retail clients in the EU |
| Futures | CME Group contract specifications |
| Live prices | Binance (crypto) and TradingView’s free chart |
| Prop firm rules | Each firm’s official website and help center |
How it is kept up to date
Prop firm rules change often, so every card shows the date they were checked and links to the official source. These are the dates of the latest review:
- FTMO: September 27, 2026
- FundedNext: September 27, 2026
- The5ers: September 27, 2026
- FundingPips: September 27, 2026
- Alpha Capital: September 27, 2026
- E8 Markets: September 27, 2026
- Topstep: September 27, 2026
- Apex Trader Funding: September 27, 2026
- Lucid Trading: September 27, 2026
- Tradeify: September 27, 2026
If you see a rule or a contract size that no longer matches, write to us with the link to the official specification and we will correct it after checking.
Independence
Sizelot doesn’t belong to any broker or prop firm and currently receives no payment from any of them. It is funded by advertising. If a link ever became an affiliate link, it would be marked next to it, and that would change neither the calculations nor the order in which firms appear.
What it doesn’t do
- It doesn’t give signals or investment advice: it only does the math with your figures.
- It doesn’t store your figures on any server: the calculations run in your browser.
- It doesn’t ask for sign-up or personal data.
Trading with leverage is risky: read the risk warning.
Contact
To report a mistake or suggest an improvement: sizelotcalculator@gmail.com.