What MetaTrader 4 is
MT4 is a broker-installed trading platform: the broker hosts the server, the trader installs the client. The platform handles charting, order entry, position management, and (via the Expert Advisor system) automated trading. It does not handle deposits, withdrawals, or KYC — those happen in the broker's separate web portal.
The platform was designed for forex trading as it existed in 2005: spot FX, CFDs on metals, and limited equity index exposure. It does not natively support stocks, futures, or options as exchange-cleared products. Its architecture is broker-bilateral by design — every order routes through the broker as counterparty, and the broker decides whether to internalise the order or hedge it through their own liquidity provider.
MT4 is offered by approximately 200 retail forex brokers globally. It dominates retail forex because of network effects: the EA ecosystem (tens of thousands of automated strategies coded in MQL4), the third-party indicator and tool library, and the trader familiarity built over two decades. Brokers continue to offer it because retail traders demand it. Its successor MT5 has not displaced it.
How MT4 handles margin, pip values, and lot sizing
MT4 displays Margin, free margin, equity, and margin level in the Trade tab of the Terminal panel. The figures update in real time as positions move. Margin is calculated from the broker's contract specifications and the account's leverage setting — MT4 displays whatever the broker sends; the platform does not enforce caps independently.
Lot sizing on MT4 uses the standard forex convention: 1.00 = 1 standard Lot size (100,000 units of base currency), 0.10 = mini lot (10,000 units), 0.01 = micro lot (1,000 units). Most retail brokers configure MT4 to accept 0.01 minimum increments; some configure 0.001 (cent accounts) for very small positions.
Pip values are not displayed prominently in the standard MT4 interface. The trader either calculates pip value externally — pip × position size in base currency, converted to account currency — or uses a third-party indicator that computes it on the chart. MT4's contract specifications dialog (right-click symbol → Specifications) shows the tick size and tick value, from which pip value can be derived.
Worked example: opening 1 standard lot of EUR/USD at 1.0850 on MT4 with 1:30 broker leverage holds $3,617 in margin (visible in the Trade tab). Pip value is $10 per pip — not displayed by MT4 directly, but inferable from contract specifications and lot size. A 50-pip move produces $500 P&L, displayed in the position's unrealised P&L column.
Placing, modifying, and closing orders
Order entry on MT4 happens through the New Order dialog (F9, or right-click chart → Trading → New Order). The dialog accepts: symbol (forex pair or CFD), volume (in lots), Stop-loss price, take-profit price, comment, and Order types type (Market Execution, Buy Limit, Sell Limit, Buy Stop, Sell Stop).
Market Execution submits an immediate order at the broker's current quote. The trader does not see the fill price before clicking; slippage during volatile conditions is accepted by the order type. Pending orders (limits and stops) submit a conditional order that activates when the market reaches the specified price. Stop-loss and take-profit can be set at order open or modified later via right-click on the open position.
Modifying an open position: right-click the position in the Trade tab → Modify or Delete Order. The dialog allows changing the stop-loss and take-profit levels. The position itself cannot be repriced (the entry is fixed at the historical fill).
Closing positions: right-click the position → Close Order. The dialog accepts a partial close (specify volume less than the open position). MT4 also supports Close-By: closing two opposing positions on the same symbol against each other, useful for hedging strategies that net out without paying double spread on close.
One-Click Trading is a toggle in MT4 settings that removes the confirmation dialog from market orders. Faster execution for active traders; higher chance of accidental orders for less-experienced users.
Broker variations on MT4
Although MT4 is the same platform, brokers configure many parameters that change the trader's experience. Lot minimums vary: 0.01 lots is standard, but cent accounts at some brokers go to 0.001 lots, and some brokers cap minimums at 0.10 lots on exotic instruments.
Spread structure differs by account type. Standard accounts typically quote 1.0–2.0 pip spreads on EUR/USD with no per-trade commission. Raw-spread (ECN) accounts quote 0.1–0.3 pip spreads with $5–10 per round-turn lot commission. The all-in cost is comparable but the breakdown differs — standard accounts pay through spread, raw accounts pay through commission.
Symbol naming conventions vary by broker. EUR/USD might appear as EURUSD, EURUSDm (mini-lot account), EURUSD.raw (raw-spread account), or EURUSD-MT4 — same underlying instrument, broker-specific suffixes. Expert Advisors written for one broker's symbol naming require adjustment to run on another.
Server time displayed on MT4 charts is broker-set. Most use a GMT+2 or GMT+3 server time aligned with the New York close at 17:00 ET. Trader confusion about session boundaries (London open, US open, market close) frequently traces back to server time vs local time mismatch.
Common mistakes on MT4
Volume field misread as units rather than lots: a trader who types 100 intending 100 units actually opens 100 standard lots — 10 million units of base currency. The position notional on EUR/USD at 1.0850 would be $108,500,000, requiring $3.6M in margin at 1:30. The broker rejects the order for insufficient margin, but the underlying confusion persists. Volume = lots, not units. Always.
One-Click Trading enabled without conscious choice: brokers often ship MT4 with One-Click Trading on by default. A trader who clicks the buy or sell button on the chart submits an immediate order with no confirmation. Disable One-Click Trading until familiarity with the order flow is established.
Stop-loss in pips vs price level: the New Order dialog accepts the stop-loss as a price level (e.g. 1.0820 for a long EUR/USD entered at 1.0850), not as a pip distance. Entering 30 in the stop-loss field would be interpreted as 30.0000 — far below the current price — and either rejected or accepted as an invalid level depending on broker validation. Always enter the absolute price level.
EA failures during fast markets: Expert Advisors rely on tick-by-tick processing. During news releases when ticks arrive in bursts, an EA may miss tick events, fail to fire stop-loss adjustments, or place orders out of intended sequence. EAs designed for normal-volatility conditions often misbehave during the seconds around major data releases.
Demo vs live account confusion: running the same EA on a demo account first, then attaching it to a live account without realising the same EA is now placing real orders. MT4 supports multiple account login profiles but the visual difference between demo and live charts is minimal. Always verify the account profile before enabling a new EA on live.