The honest short answer: if you are starting today and your broker offers both, run your Expert Advisors on MT5. The longer answer matters because a lot of traders have working MT4 setups, a lot of brokers still run MT4 servers, and a lot of excellent robots were written in MQL4 and never ported. Here is what actually differs for someone who wants to run automated strategies, not write them.
They are not compatible with each other
An MT4 EA is an .ex4 file compiled from MQL4; an MT5 EA is an .ex5 compiled from MQL5. Neither runs on the other platform, and there is no converter that works for anything non-trivial. If a robot you want is MT4-only, you run MT4 — and vice versa. Sellers who support both ship two separate builds (Quantora EA is one example: same strategy, two products).
Where MT5 is clearly better for EAs
- Strategy Tester: multi-currency testing, real-tick history from the broker, forward testing on an out-of-sample period, and much faster execution on a 64-bit engine. Backtesting a Gold grid over five years takes minutes on MT5 and can take hours on MT4.
- Timeframes: 21 versus 9. M2, M3, H2, H6, H8, H12 exist natively — useful for EAs whose logic was built on them.
- Netting or hedging accounts: the broker chooses per account type. Hedging mode behaves like MT4 (separate positions per order); netting merges everything on a symbol into one position. Grid and basket EAs need hedging mode — check before opening an account.
- Depth of market, economic calendar and more order types (buy stop limit, sell stop limit) built in.
- Active development. MetaQuotes has focused new features on MT5 for years; MT4 receives maintenance updates.
Where MT4 still wins
- Broker coverage: nearly every broker runs MT4, and some regional brokers offer Gold and index CFDs only on MT4.
- Existing robots and indicators: the MQL4 library is enormous, and many traders' custom tools were never ported.
- Simplicity: one account model (hedging), a smaller settings surface, and a tester that, while slow, is familiar.
- Lighter on resources — relevant on the cheapest VPS plans.
Backtest quality is the deciding factor
For an EA buyer the tester is the thing that matters most, because it is how you check a seller's claims before risking money. MT5's "Every tick based on real ticks" mode replays the broker's actual tick stream, spreads included. MT4's best mode generates ticks from one-minute bars and uses a fixed spread, which flatters grid and scalping strategies in particular. A strategy that looks the same in both is robust; one that only looks good on MT4 modelling deserves suspicion.
Hedging vs netting: the trap for grid EAs
On an MT5 netting account, buying 0.01 lots three times gives you one 0.03-lot position with an averaged entry — the individual grid levels, and their individual take-profits, no longer exist. Grid, basket and averaging EAs assume hedging mode. If your broker's MT5 account is netting (common with exchange-style brokers), either open a hedging account type or use MT4. Most retail forex and CFD brokers default to hedging on MT5; the account specification page says which.
Migrating from MT4 to MT5
- Open the MT5 account with the same broker first and confirm the symbol names, contract sizes and swap rates match what you were trading.
- Buy or re-download the MT5 build of each EA — an MT4 purchase on the MQL5 Market does not include the MT5 version unless the seller lists them as one product.
- Backtest on MT5 with real ticks before going live; expect slightly worse numbers than your MT4 tests showed. That is the more honest picture, not a worse robot.
- Run both platforms in parallel on demo for a couple of weeks; the MT5 build of a ported EA may have inputs with different names or defaults.
Bottom line
Choose MT5 unless something specific forces MT4: the broker, an account type, or a robot that only exists there. If you are stuck on MT4, it still works fine for live trading — just be more sceptical of MT4 backtests and lean on live Myfxbook records instead.
