Custom MT4 indicator

Build an MQL4 VWAP indicator with explicit volume assumptions

MQL4 has no universal one-call VWAP function. A custom indicator can accumulate typical price times volume and divide by cumulative volume, but MT4’s standard Volume series contains tick volume. Label the result as tick-volume-weighted unless the broker supplies another verified volume source.

Open MQL4 Coding Agent Review the code example

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

DailyTickVWAP.mq4MQL4

#property strict
#property indicator_chart_window
#property indicator_buffers 1

double VwapBuffer[];

int OnInit()
  {
   if(!SetIndexBuffer(0, VwapBuffer))
      return(INIT_FAILED);
   ArraySetAsSeries(VwapBuffer, true);
   SetIndexStyle(0, DRAW_LINE, STYLE_SOLID, 2, clrBlue);
   SetIndexLabel(0, "Daily Tick VWAP");
   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[])
  {
   ArraySetAsSeries(time, true);
   ArraySetAsSeries(high, true);
   ArraySetAsSeries(low, true);
   ArraySetAsSeries(close, true);
   ArraySetAsSeries(tick_volume, true);

   double cumulative_pv = 0.0;
   double cumulative_volume = 0.0;

   for(int i = rates_total - 1; i >= 0; i--)
     {
      bool new_day = (i == rates_total - 1);
      if(!new_day)
         new_day = (TimeDay(time[i]) != TimeDay(time[i + 1]) ||
                    TimeMonth(time[i]) != TimeMonth(time[i + 1]) ||
                    TimeYear(time[i]) != TimeYear(time[i + 1]));

      if(new_day)
        {
         cumulative_pv = 0.0;
         cumulative_volume = 0.0;
        }

      double bar_volume = (double)tick_volume[i];
      double typical_price = (high[i] + low[i] + close[i]) / 3.0;
      cumulative_pv += typical_price * bar_volume;
      cumulative_volume += bar_volume;

      VwapBuffer[i] = (cumulative_volume > 0.0)
                      ? cumulative_pv / cumulative_volume
                      : EMPTY_VALUE;
     }

   return(rates_total);
  }

Typical price is an explicit choice
MT4 Volume is tick volume
Session reset defines the anchor
Zero-volume bars need a guard

VWAP is a formula plus an anchor

The numerator accumulates price multiplied by volume. The denominator accumulates volume. The anchor decides when both totals reset. A daily indicator, a broker session, a week, and an event-anchored calculation can produce different lines from the same bars.

Typical price using high, low, and close is one common source, but close-only or another defined source is also possible. The page or indicator name should state that choice.

Use this daily reset example on intraday charts. Daily or higher bars do not reconstruct intraday VWAP. If the oldest loaded history starts partway through a day, that first day is only a partial accumulation; load earlier bars before comparing it with a complete session.

Decision	Example in this code	Alternative
Price source	(high + low + close) / 3	Close or another defined price
Weight	tick_volume	Verified broker-provided real volume
Anchor	Calendar day in server timestamps	Session, week, or event
Zero denominator	EMPTY_VALUE	Carry-forward only if explicitly intended

Tick volume is not exchange trade volume

The official MQL4 predefined Volume array contains tick volumes for bars on the current chart. That is a count of price updates, not a guaranteed count of contracts or shares traded on a centralized venue.

Broker feeds and server sessions can differ. A VWAP-style line from one MT4 feed should not be presented as identical to exchange VWAP without evidence about the source.

Name the indicator Daily Tick VWAP or disclose the weight source
Use server timestamps when defining daily boundaries
Test Sunday candles and broker session gaps
Recalculate after deeper history loads or chart changes

Verify the plotted line before using it as a signal

Compare several bars with a hand calculation and check where the daily reset occurs. Reload the chart and change timeframe to confirm the line rebuilds consistently from available data.

A price crossing this line is not automatically a profitable rule. Define confirmation, bar timing, costs, stops, and invalidation before testing any strategy interpretation.

Review the complete example

The indicator explicitly sets its output buffer and all accessed input arrays to series indexing, then walks from the oldest loaded bar toward the current bar. It resets at server calendar-day boundaries, uses typical price weighted by tick_volume, and avoids division by zero. It recalculates loaded history on every call for clarity.

This is a tick-volume-weighted reference indicator, not an exchange-volume claim or a trading recommendation. Verify feed, session, and history behavior in the target MT4 installation.

DailyTickVWAP.mq4MQL4

#property strict
#property indicator_chart_window
#property indicator_buffers 1

double VwapBuffer[];

int OnInit()
  {
   if(!SetIndexBuffer(0, VwapBuffer))
      return(INIT_FAILED);
   ArraySetAsSeries(VwapBuffer, true);
   SetIndexStyle(0, DRAW_LINE, STYLE_SOLID, 2, clrBlue);
   SetIndexLabel(0, "Daily Tick VWAP");
   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[])
  {
   ArraySetAsSeries(time, true);
   ArraySetAsSeries(high, true);
   ArraySetAsSeries(low, true);
   ArraySetAsSeries(close, true);
   ArraySetAsSeries(tick_volume, true);

   double cumulative_pv = 0.0;
   double cumulative_volume = 0.0;

   for(int i = rates_total - 1; i >= 0; i--)
     {
      bool new_day = (i == rates_total - 1);
      if(!new_day)
         new_day = (TimeDay(time[i]) != TimeDay(time[i + 1]) ||
                    TimeMonth(time[i]) != TimeMonth(time[i + 1]) ||
                    TimeYear(time[i]) != TimeYear(time[i + 1]));

      if(new_day)
        {
         cumulative_pv = 0.0;
         cumulative_volume = 0.0;
        }

      double bar_volume = (double)tick_volume[i];
      double typical_price = (high[i] + low[i] + close[i]) / 3.0;
      cumulative_pv += typical_price * bar_volume;
      cumulative_volume += bar_volume;

      VwapBuffer[i] = (cumulative_volume > 0.0)
                      ? cumulative_pv / cumulative_volume
                      : EMPTY_VALUE;
     }

   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.

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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
Choose price and volume sources
Document the price formula and whether the weight is tick or verified real volume.
2
Define the anchor
Select calendar day, broker session, week, or another reset event.
3
Accumulate with guards
Reset both totals together and avoid division when cumulative volume is zero.
4
Compare plotted values
Check hand-calculated bars, session boundaries, reloads, and timeframe changes.

Frequently asked questions

Does MQL4 have a built-in VWAP function?

MQL4 does not provide a universal one-call VWAP function in its standard technical indicator list. A custom calculation must define price, volume, and anchor.

What volume does MT4 use for VWAP?

The standard MQL4 Volume series contains tick volume. Do not label it exchange trade volume without another verified source.

When should an MQL4 VWAP reset?

The reset depends on the intended anchor. This example resets by calendar day using server-time bar timestamps.

Why does VWAP differ between MT4 brokers?

Tick feeds, server sessions, history, symbols, and available volume sources can differ between brokers.

Can a VWAP crossover guarantee a trade outcome?

No. The line is a calculation. A trading rule still needs defined timing, execution assumptions, risk controls, and validation.

Official references

Related MQL4 resources

MT4 indicators MQL4 event handlers MQL4 AI Coding Agent

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.

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