MT5 expert advisor settings for beginners: inputs, lot size and permissions explained

MT5 expert advisor settings for beginners: the short answer

MT5 expert advisor settings fall into two groups: the inputs inside the EA (lot size, stop loss, magic number, trading hours) and the permissions in the platform (Algo Trading button, allowed imports, per-EA options). Understand both groups before you test anything. A wrong lot size or a blocked permission is the most common reason a beginner thinks an EA is broken or, worse, behaves in an unexpected way.

This guide explains what each common field does and how to read it. It does not recommend any setting as profitable, because no setting is. Treat every value here as an example to understand, not a configuration to copy.

Where EA settings live in MT5

There are three places to look, and beginners often confuse them.

1. The Inputs tab in the EA properties window, which opens when you drag an EA onto a chart or press F7 on a chart with an EA attached. These are the strategy parameters set by the developer.
2. The Common tab in the same window, which holds per-EA permissions such as Allow Algo Trading and trade direction limits.
3. Tools > Options > Expert Advisors, which holds platform-wide rules, such as whether automated trading is allowed at all and whether DLL or WebRequest access is permitted.

The official MetaTrader 5 documentation describes each of these windows. Check it if your build looks different, since broker versions can vary slightly.

Common EA inputs and what they mean

Input names differ between developers, but most EAs share a familiar set. Hover over or read the developer's documentation for exact meaning, since the same name can behave differently in different code.

Lot size and risk mode

Lot size is the trade volume. On many forex symbols, 1.00 lot equals 100,000 units of the base currency, 0.10 is a mini lot and 0.01 is a micro lot. Contract specifications differ by broker and symbol, so check the Market Watch specification window for each instrument.

Some EAs offer a fixed lot input. Others offer a risk-percent mode that calculates volume from account equity and stop distance. If an EA has both, confirm which one is active. A typical mistake is leaving a risk-percent field at a default meant for a larger account.

A worked example on EURUSD: with a standard contract of 100,000 units, a 0.10 lot position moves roughly 1 dollar per pip for a USD-denominated account (0.10 lot is 10,000 units, and a pip of 0.0001 times 10,000 is 1 dollar). A 1.00 lot position moves roughly 10 dollars per pip. Always verify against your own broker specification rather than trusting this approximation.

For futures-style symbols such as ES or NQ offered on some MT5 brokers as CFDs, the contract size and tick value differ again. For the real exchange contract, consult the CME Group contract specifications. An ES tick is 0.25 index points worth 12.50 dollars, which shows why volume units cannot be assumed equal across markets.

Stop loss, take profit and trailing

These are usually expressed in points, not pips. On a five-digit EURUSD quote, 10 pips equals 100 points. Misreading points as pips can make a stop ten times tighter or wider than intended. Check how many digits your symbol has before entering values.

Trailing stop inputs usually include a trigger distance and a step. Read the description so you know when the stop begins to move.

Magic number and comment

The magic number is an ID that lets the EA recognize its own orders. If you run two EAs or the same EA on two charts, give each a different magic number. Otherwise one may manage or close the other's trades. The comment field is only a label.

Time filters and session inputs

Many EAs let you restrict trading to certain hours. These hours normally follow server time, not your local time. A broker server may run on GMT+2 or GMT+3, so a start hour of 9 may not mean 9 a.m. where you live. Confirm the server clock in Market Watch before trusting any time filter.

Spread, slippage and max trades

Maximum spread blocks entries when the spread is wide. Maximum slippage (deviation) sets how far from the requested price a fill can occur. Max open trades caps exposure. These are protective settings and worth understanding early. On CL or news-sensitive pairs, spreads can widen sharply around releases, so a spread filter that is too loose may let trades through at poor prices.

Automated trading permissions explained

Even perfect inputs do nothing if permissions block the EA.

The Algo Trading button

The toolbar button labeled Algo Trading is the global switch. When it is off, no EA can send orders. When on, EAs with permission can trade. A small icon in the top-right corner of the chart shows whether that specific EA is active, typically a smiley or a hat-like icon, depending on build.

Allow Algo Trading in the Common tab

Each EA also needs Allow Algo Trading ticked in its own properties. If the global button is on but this box is off, the EA will run its logic without sending orders.

Allow DLL imports and WebRequest

Some EAs call external libraries or web addresses, for example for licensing or news data. Enable these only if you understand why the EA needs them. DLL access lets external code run on your computer, so be cautious and only allow it for software from a source you trust. WebRequest requires you to add specific URLs in Tools > Options > Expert Advisors, which is safer than a blanket permission.

Allow live trading and trade direction

The Common tab may also let you limit direction to long only, short only or both. Use this deliberately, since a leftover restriction can explain why an EA never opens one type of trade.

A beginner pre-run checklist

1. Open the Inputs tab and read every field before pressing OK.
2. Confirm lot size mode and the exact volume against the symbol specification.
3. Check whether stops are in points or pips and how many digits the symbol uses.
4. Assign a unique magic number.
5. Verify the time filter against server time.
6. Confirm the global Algo Trading button and the per-EA permission.
7. Decline DLL access unless there is a clear, trusted reason.
8. Run it first on a demo account, never straight on live funds.

If you are still deciding whether an EA deserves your time, the due-diligence checklist for buying an MT5 expert advisor covers vendor and documentation checks. Once the settings are understood, the next step is testing an expert advisor in the MT5 Strategy Tester, where inputs are loaded from a preset and results are read from the report.

Saving and reusing presets

In the Inputs tab, the Save button writes a .set file containing your values, and Load restores it. Save a preset before changing anything, so you can return to a known configuration. Note that the Strategy Tester has its own inputs tab, and values there do not automatically match the ones on your live chart. Compare them if results look different from what you expected.

Common beginner mistakes

• Leaving default lot sizes without checking against account size.
• Confusing points with pips.
• Running two EAs with the same magic number.
• Assuming time filters use local time.
• Enabling DLL imports without knowing what the library does.
• Changing several inputs at once, which makes it impossible to see what caused a different result.

Change one input at a time and record what you changed. Past test results do not predict future performance, and any EA can lose money.

Conclusion

MT5 expert advisor settings are easier once you separate strategy inputs from platform permissions. Read each input, verify lot size and units against the symbol specification, check the time basis, and confirm the Algo Trading switches at both the global and per-EA level. Then test on a demo account before any live use. For explore-first learners, SierraOnShop offers MT5 expert advisors, robots and Sierra Chart order flow tools you can study alongside your own testing.

FAQ

Why is my EA attached but not placing trades?

The usual causes are the global Algo Trading button being off, Allow Algo Trading unchecked in the EA's Common tab, a time or spread filter blocking entries, or the market being closed. Check the Experts and Journal tabs in the Toolbox for error messages.

What lot size should a beginner use?

There is no universal answer. Use the smallest volume your broker allows, often 0.01 lot, while you learn how the EA behaves on a demo account. Then choose a size based on your own risk limits, not on a number from a seller.

Can I use the same settings on different symbols?

Not safely without checking. Digits, contract size, spread and volatility differ between EURUSD, NQ-based CFDs and CL, so stop distances and lot values may mean very different things.

Do I need to keep MT5 open for an EA to run?

Yes. The EA runs inside the terminal, so MT5 must stay open and connected. Many traders use a VPS for continuous operation, but that is optional and adds its own setup and cost.