How Does a Trade Copier Work? (MT5 Explained)

By Rise Together FX team · 11 min read

Master trading terminal sending a trade ticket through a copier box to three follower terminals

A trade copier is software that watches one trading account and repeats its trades in one or more other accounts. It's the plumbing behind most copy-trading setups on MetaTrader 5 (MT5). This guide explains, in neutral technical terms, how copiers work, the settings that change what ends up in your account, and the ways copying can go wrong. It doesn't review or compare any particular product.

Trading forex and CFDs is high risk and you can lose all the money you put in. Most retail CFD accounts lose money. This article is general education, not financial advice.

What a trade copier does

At its simplest, a copier does three jobs:

Detects when a trade is opened, changed or closed on a source account.
Translates that trade for each receiving account: working out the size, matching the instrument name, and applying any settings.
Sends the matching order to each receiving account's broker.

It repeats this for every change: new trades, stop loss or take profit changes, partial closes and full closes. A copier doesn't decide what to trade. It only repeats what happens on the source account, within the rules it's given.

Master and follower accounts

Copiers usually use two roles:

Master (also called provider, source or sender): the account whose trades are copied.
Follower (also called receiver, slave or copier account): the account that receives the copied trades.

One master can feed many followers, and the followers don't have to be at the same broker as the master.

What access each account needs

To copy, the software needs to see the master's trades and to place trades on the follower account.

To place trades on the follower account, a copier needs trading access to it. That means giving a third party a lot of control. It's worth knowing exactly what access you're giving, to whom, and how to remove it. Changing your password, for example, removes access granted with the old one, but any trades already open stay open, and nothing is then managing them.

Local (EA-based) vs cloud copiers

Local copiers

A local copier runs inside the MT5 platform as an Expert Advisor (EA), a program that can trade automatically. You typically run one copy of the platform for the master and one for each follower, on the same computer, and the EAs pass trades between them.

It depends on that computer. If the computer is switched off, sleeps, loses its internet connection or crashes, copying stops. MT5's own help notes that trading robots and signal subscriptions need a constant connection to the trade server and an uninterrupted power supply.
Many people run it on a VPS. A virtual private server is a remote computer that runs all the time. It reduces the risk of a home computer going off but adds its own points of failure.
You control the software and settings, which also means you're responsible for them.

For more on EAs, see What is an Expert Advisor in MT5?

Cloud copiers

A cloud copier runs on the provider's servers. It connects to the master and follower accounts using their login details, so nothing needs to be running on your own computer.

Nothing to keep switched on at home, but you're relying on the provider's servers, its connection to each broker, and its security.
You're giving a third party your login details. As above, that includes trading access to the follower account.
Settings are controlled through the provider's website or app, and may be set by you, by the service or by both.

Neither type is automatically better. Both can stop working, both can copy incorrectly if set up wrongly, and neither changes the risk of the strategy being copied.

Lot scaling and risk multipliers

The setting that most affects your account is how trade size is worked out. Follower accounts are rarely the same size as the master, so copiers offer ways to scale the size. Common options are:

Fixed lot: every copied trade uses the same size you set, whatever the master trades.
Lot multiplier: the follower trades a set multiple of the master's size (for example 0.5×, 1× or 2×).
Balance or equity ratio: the follower's size is scaled by the ratio of the follower's account to the master's, so the follower carries roughly the same risk in proportion to its size.
Risk multiplier on top: some copiers let you increase or decrease the proportional size, for example "1.5× proportional".

Illustrative example (made-up numbers to show the mechanics; not based on any real account or on our strategy):

Master account equity: £10,000. It opens a trade of 0.50 lots.
Follower account equity: £2,000, one-fifth the size of the master.

Setting	Follower trade size	Risk relative to the master, as a share of the account
Equity ratio	0.50 × (2,000 ÷ 10,000) = 0.10 lots	About the same
Equity ratio with 2× risk multiplier	0.20 lots	About twice as much
Lot multiplier 1× (same as master)	0.50 lots	About five times as much
Fixed lot 0.05	0.05 lots	About half

A setting that looks harmless, such as "copy the same size", can carry far more risk in a smaller account. A small account copying a large one at the same lot size can be wiped out by a move the master account handles comfortably.

Equity-ratio sizing also changes as accounts grow or shrink. If the follower's equity falls, later trades get smaller. If you add or withdraw money, sizes change too. For a refresher on lots, see Forex lot size explained.

Minimum lot size and rounding

Brokers set a minimum trade size and a size step. On MT5, these are set by the broker for each instrument, often 0.01 lots minimum with a 0.01 step. When scaling gives a size the broker doesn't allow, the copier has to round it.

Illustrative example (made-up numbers): the master opens 0.03 lots, and the follower's ratio is 0.2. The scaled size is 0.006 lots, below a 0.01 minimum.

If the copier rounds up to 0.01 lots, the follower carries about 1.7 times the proportional risk on that trade.
If the copier rounds down to zero, the trade is skipped, and the follower's results will drift from the master's.

For strategies that open several small trades, such as grid strategies, rounding can make a small follower account carry noticeably more risk than its size suggests. It's worth checking how a copier handles this before relying on it.

Symbol mapping between brokers

Different brokers can name the same instrument differently: for example EURUSD, EURUSD.a, EURUSDm or EURUSD.pro. A copier needs a symbol map that tells it which name on the follower's broker matches each name on the master's.

Mapping problems can cause:

Missed trades: the copier can't find the instrument and doesn't copy.
Wrong instrument: a mistake in the map copies a trade to the wrong market.
Wrong size: instruments with the same name can have a different contract size at different brokers (MT5 shows this in each symbol's specification). If one broker's "1 lot" is a different amount from another's, a copier that copies lot-for-lot can open a position of a very different real size.

Prices also differ slightly between brokers, as do spreads and trading hours, so even a correctly mapped trade can open and close at different prices.

Latency, slippage and missed copies

Latency is the delay between the master trade and the follower trade. It includes the time to detect the trade, process it and send the order to the follower's broker. It's often a fraction of a second, but it can be longer, especially if a server is far from the broker or a connection is slow.

During that delay, the price can move:

Slippage: a market order is filled at the price available when it reaches the broker, which can be worse than the master's price. In fast markets, such as around major news, the difference can be large.
Requotes and rejections: some brokers may reject an order or offer a new price if the price has moved, which can mean a trade isn't copied.
Not enough free margin: if the follower account doesn't have enough margin, the broker refuses the trade.

Each of these makes the follower's results different from the master's. Over many trades, small differences add up, and they can be larger for strategies that trade often.

What happens when you disconnect

Copying only works while every link is up: the master account, the copier and the follower account. When one part drops out, what happens depends on the copier and its settings, so it's worth finding out in advance.

Typical situations:

The follower side goes offline (computer off, VPS down, connection lost). New master trades aren't copied. If the master closes a trade while the follower is offline, the follower's trade stays open with nobody managing it, unless it has its own stop loss or take profit at the broker.
The copier reconnects. Some copiers then try to match the master, for example by closing trades that the master has closed. Others don't, and leave you to sort it out. Prices may have moved a long way by then.
The master side goes offline. No new trades or closes are sent. Follower trades remain open.
Partial closes. If the master closes part of a trade, the copier has to work out the matching part for each follower. Rounding to the minimum size can leave a small part open, or close all of it.
Weekends and gaps. Markets close over the weekend, and prices can open on Monday a long way from Friday's close. A copier can't act while the market is closed.

Your broker's margin close-out (stop out) works on your account regardless of the copier. If losses use up your margin, the broker can close positions whether the copier is connected or not. See What is copy trading? for how this fits together.

What a copier can't do

A copier is a delivery mechanism. It's worth being clear about its limits:

It doesn't make a strategy less risky. Copying a high-risk strategy gives you a high-risk account. If the strategy loses heavily, so do you, and you could lose all the money in your account.
It won't give identical results. Prices, timing, sizes and costs differ.
It can add risk. Wrong settings, rounding, mapping errors and disconnections can all make outcomes worse than the master's.
It doesn't protect you from scams. A legitimate-looking copier can be connected to a strategy that isn't what it claims.
It doesn't replace checking who you're dealing with. The FCA treats copy trading with automatic execution and no manual input from you as portfolio management, which needs authorisation. See Copy trading risks.

Glossary

Trade copier: software that repeats trades from one account in other accounts.
Master account: the account whose trades are copied.
Follower account: the account that receives copied trades.
Expert Advisor (EA): a program that runs inside MetaTrader and can trade automatically.
VPS (virtual private server): a remote computer that runs all the time, often used to keep trading software online.
Lot: a standard unit of trade size. 0.01 lots is a micro lot.
Lot scaling: the rule a copier uses to work out each follower's trade size.
Symbol mapping: matching instrument names between different brokers.
Contract size: how much of an instrument one lot represents at a given broker.
Latency: the delay between a trade on the master and the copied trade on the follower.
Slippage: the difference between the expected price and the price a trade is actually filled at.
Stop out: when the broker starts closing positions because the account doesn't have enough margin.

More terms in our glossary.