Pine Script to MetaTrader 4

Convert Pine Script to MQL4 without literal translation

Pine Script and MQL4 use different execution and trading models, so reliable conversion is a behavioral rewrite rather than token replacement. Define the source behavior, map series and bar-close rules, choose an MQL4 EA or indicator, then compile and compare outputs on the same data.

Open MQL4 Coding Agent Review the code example

Open the Coding Agent, then choose MQL4 from the language menu.

ConvertedMovingAverage.mq4.mq4

#property strict
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 clrDodgerBlue

input int Length = 20;
double AverageBuffer[];

int OnInit()
  {
   if(Length < 1)
      return(INIT_PARAMETERS_INCORRECT);

   SetIndexBuffer(0, AverageBuffer);
   SetIndexStyle(0, DRAW_LINE);
   SetIndexLabel(0, "SMA");
   return(INIT_SUCCEEDED);
  }

int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
   if(rates_total < Length)
      return(0);

   int limit = rates_total - prev_calculated;
   if(prev_calculated > 0)
      limit++;
   if(limit > rates_total - Length)
      limit = rates_total - Length;

   for(int shift = limit; shift >= 0; shift--)
      AverageBuffer[shift] = iMA(NULL, 0, Length, 0,
                                 MODE_SMA, PRICE_CLOSE, shift);

   return(rates_total);
  }

Map behavior, not syntax alone
Choose EA or custom indicator
Preserve bar and session semantics
Compile and compare outputs

Map the execution model first

Pine evaluates a script across dataset bars and re-executes the realtime bar as updates arrive. MQL4 dispatches terminal events to an EA, custom indicator, or script. The conversion must state when each signal becomes final and which event owns it.

A Pine indicator usually maps to an MQL4 custom indicator with buffers and OnCalculate. A Pine strategy usually maps to an Expert Advisor, but TradingView simulated orders do not map one-to-one to broker OrderSend, OrderModify, and OrderClose calls.

Pine concept	MQL4 target	Conversion question
indicator() and plot()	Custom indicator and buffers	Which values and styles are drawn?
strategy.entry / exit	EA trade state machine	How are fills, stops, and ownership modeled?
Series history operator	Timeseries shift	Is current or closed bar intended?
request.security	Cross-symbol/timeframe functions	How are gaps and alignment handled?

Preserve semantics that syntax cannot express

Inputs, sessions, timezone, warmup length, missing data, lookahead behavior, pyramiding, commission, slippage, order timing, and repaint behavior all affect output. Record them before rewriting the formula.

Built-in functions with similar names can use different initialization or missing-value behavior. Compare known bars and intermediate series rather than trusting visual similarity on one chart.

Freeze the Pine version and complete source
List every external symbol, timeframe, and session dependency
Define shift 0 and bar-close behavior explicitly
Separate indicator parity from broker execution parity

Use both language toolchains

Pineify provides a dedicated Pine Script Coding Agent for the source side and an MQL4 Coding Agent for the target side. The converter workflow can use each language context while keeping the behavioral specification between them.

A generated MQL4 file still needs MetaEditor compilation, MT4 chart comparison, Strategy Tester checks for an EA, and demo validation for broker operations.

Review the complete example

This MQL4 custom indicator represents a plotted simple moving average. The main conversion decision is not the formula but the target program type, buffer lifecycle, shift direction, and recalculation boundary.

Generated conversion requires side-by-side value comparison. An EA also needs Strategy Tester and demo-account verification because platform fill models and broker execution differ.

ConvertedMovingAverage.mq4.mq4

#property strict
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 clrDodgerBlue

input int Length = 20;
double AverageBuffer[];

int OnInit()
  {
   if(Length < 1)
      return(INIT_PARAMETERS_INCORRECT);

   SetIndexBuffer(0, AverageBuffer);
   SetIndexStyle(0, DRAW_LINE);
   SetIndexLabel(0, "SMA");
   return(INIT_SUCCEEDED);
  }

int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
   if(rates_total < Length)
      return(0);

   int limit = rates_total - prev_calculated;
   if(prev_calculated > 0)
      limit++;
   if(limit > rates_total - Length)
      limit = rates_total - Length;

   for(int shift = limit; shift >= 0; shift--)
      AverageBuffer[shift] = iMA(NULL, 0, Length, 0,
                                 MODE_SMA, PRICE_CLOSE, shift);

   return(rates_total);
  }

Where Pineify fits

Move from the rule to editable MQL4 source

Pineify can generate or revise one self-contained .mq4 file with MQL4-specific reference context. Its independent static checker returns MetaEditor diagnostics so you can repair source issues before testing in your own MT4 environment.

Also relevant: Pine Script AI Coding Agent. Use the Pine Script agent to explain and stabilize the source behavior before rewriting it for MQL4.

Open MQL4 Coding Agent

Static diagnostics do not prove runtime behavior, backtest results, broker compatibility, or live-trading safety.

Pineify MQL4 Coding Agent with MQL4 selected and an editable MetaTrader 4 code artifact

A practical workflow

1
Specify Pine behavior
Capture version, inputs, outputs, sessions, bar timing, external data, and strategy settings.
2
Choose the MQL4 program type
Use a custom indicator for chart output or an EA for broker-order behavior.
3
Rewrite the state model
Map series history, persistent variables, recalculation, and order ownership explicitly.
4
Compare and validate
Compile, compare values on matching bars, then test trading behavior separately.

Frequently asked questions

Can Pine Script be converted automatically to MQL4?

Simple indicators can be assisted heavily, but reliable conversion still requires decisions about runtime, bars, sessions, state, and trading behavior.

Does a Pine strategy become an MQL4 indicator?

Usually not. A strategy that places simulated orders normally requires an MQL4 Expert Advisor, while its visual calculations may also need indicator buffers or chart objects.

What is the MQL4 equivalent of plot?

A custom indicator commonly uses an indicator buffer with SetIndexBuffer and a drawing style.

Why do converted signals differ by one bar?

The source and target may disagree about the current bar, closed bars, update timing, lookahead, or cross-timeframe alignment.

Does successful compilation prove conversion parity?

No. It proves source validity. Compare intermediate and final values on the same market data and test order behavior independently.

Official references

Related MQL4 resources

MQL4 AI Coding Agent Pine Script AI Coding Agent MT4 to MT5 EA converter

Last verified against the linked official references on August 9, 2026. Compile and test the final source in the MetaTrader 4 build, broker, symbol, and account environment you plan to use.

Continue with one reviewable MQL4 file

Define the requirement, inspect the generated source, repair diagnostics, and test the behavior in your own MT4 environment.

Open Coding Agent