For backtesting specifically, this is not a close contest: MT5 is clearly better, and both are free. The interesting questions are how much the difference actually changes your results (measurably, it depends on your stop distance) and whether the migration cost is worth paying if your strategies are written in MQL4.
MT4 cannot use real tick data. It generates ticks by interpolating between one-minute bars — inventing a plausible path through each bar. MT5 can replay actual tick data recorded by your broker.
Everything else follows from that. Here is the full comparison, checked against MetaQuotes documentation on 17 August 2026:
| Capability | MT4 | MT5 |
|---|---|---|
| Real tick data | No | Yes |
| Tick generation modes | Interpolated only | 5 modes |
| Multi-core optimisation | No | Yes |
| Genetic optimisation | No | Yes |
| Built-in forward testing | No | Yes |
| Multi-currency testing | No | Yes |
| Manual bar-by-bar trading | No | No |
| Language | MQL4 | MQL5 |
| Price | Free | Free |
The single most valuable MT5 feature is the least discussed: built-in forward testing. It reserves a slice of history the optimiser never sees, so you can check whether optimised parameters survive on unseen data. That is the best defence against overfitting available in free software, and MT4 simply has nothing equivalent.
"More accurate" is not a decision criterion unless you know the size of the effect. It is measurable, and it depends almost entirely on how tight your stops are.
Across 1,911,141 EURUSD one-minute bars from 2021 to 2026, aggregated into 31,852 hourly bars, counting bars where the take-profit and stop were both touched — meaning the bar cannot say which came first:
| Bracket | Ambiguous bars | % of bars | Resolution matters? |
|---|---|---|---|
| ±5 pips | 5,239 | 16.45% | Decisively |
| ±10 pips | 959 | 3.01% | Somewhat |
| ±20 pips | 77 | 0.24% | Barely |
| ±40 pips | 3 | 0.01% | No |
When the underlying minute data resolves those ambiguous cases, the stop is hit first almost exactly half the time — 50.06% at a 5-pip bracket. A coin flip.
What that means for this comparison: if you scalp with tight stops, MT4's interpolated ticks are guessing on roughly one trade in six, and MT5's real ticks are a genuine upgrade. If your stops are 40 pips wide, the platforms will produce nearly identical results and MT5's advantage lies entirely in optimisation speed and forward testing instead. The full study is here, and the script is in the repository so you can re-run it.
MT5 is better at testing, and yet most retail forex traders are still on MT4. The reasons are real rather than inertia:
The honest recommendation: if you are starting fresh, use MT5. It is free, strictly better at testing, and there is no reason to adopt the older platform today. If you have a working MQL4 strategy and wide stops, porting it buys you optimisation speed and forward testing — worthwhile, but not urgent.
Whichever you use, the setting that decides whether your backtest means anything is the modelling mode. MT5's five modes, as MetaQuotes names them:
| Mode | Use it? |
|---|---|
| Every tick based on real ticks | Yes — the only mode to trust for short-term strategies |
| Every tick | Acceptable — accurate simulation, but the ticks are invented |
| 1 minute OHLC | Adequate for slow strategies only |
| Open prices only | Optimisation triage only. Never report a result from it |
| Math calculations | Not a backtest at all |
And the number that misleads everyone: the "modelling quality" percentage is a data-coverage score, not an accuracy score. It tells you whether the tester had enough history to build ticks. A curve-fitted strategy with unrealistic stops will happily report 99%. More on this in the MT5 Strategy Tester review.
A large share of people comparing MT4 and MT5 for "backtesting" want to step through history placing trades by hand. Neither platform does that, and no setting enables it.
Two ways out. Soft4FX adds manual trading to MetaTrader for $109 plus tax one-time, covering MT4 and MT5 both — the right answer if your indicators and workflow already live there. Or FXAbsolute does it in a browser for free: 28,412,683 one-minute bars across 15 instruments from 2021 to 2026, with drawing tools, limit orders and an automatic journal, and no account or install. It also runs on macOS and phones, which neither MetaTrader does.
Its limits, plainly: no spread modelling, no automation, and five years rather than twenty. For discretionary practice those rarely bind; for a coded scalping system they rule it out entirely, and MT5 with real ticks is the correct tool.
Yes, clearly. MT5 supports real broker tick data, five tick generation modes, multi-core and genetic optimisation, multi-currency testing and built-in forward testing. MT4 has none of these and models ticks by interpolating from one-minute bars. Both are free, so if you are starting fresh there is no reason to choose MT4.
It depends on your stop distance. Measured across 1,911,141 EURUSD one-minute bars, a 5-pip bracket left 16.45% of hourly bars ambiguous, where interpolated ticks are effectively guessing. At a 40-pip bracket only 0.01% of bars were ambiguous, so the two platforms would produce nearly identical results for wide-stop strategies.
Not directly. MQL4 and MQL5 differ enough that Expert Advisors need rewriting, and if you did not write the strategy yourself, porting may not be possible. This is the main reason many traders remain on MT4 despite MT5 being the better testing platform.
No. Both Strategy Testers run Expert Advisors, meaning coded strategies, and visual mode only lets you watch an EA trade rather than place trades yourself. For manual discretionary backtesting you need the Soft4FX add-on at $109 plus tax, which covers both platforms, or a browser tool such as FXAbsolute which is free.
Every tick based on real ticks, which replays actual broker tick data rather than simulating it. Plain "every tick" is a good simulation but the ticks are generated. "Open prices only" and "math calculations" should never be used to judge a strategy — only to triage parameters quickly during optimisation.
No. Modelling quality measures how completely the tester could build ticks from available history — it is a data-coverage score. A curve-fitted strategy with unrealistically tight stops and assumed spread can report 99% modelling quality. It answers whether the tester had enough data, not whether the result is trustworthy.
Neither MetaTrader lets you trade history by hand. FXAbsolute does — five years of real one-minute data, free, no account, no install.
Open FXAbsolute →