length gives the number of characters, you need to use $content->advancewidth($text). Here is a demo 
#!perl
use strict;
use PDF::API2;
my $pdf = new PDF::API2(-file => "align.pdf");
$pdf->mediabox(842, 595); #A4 Landscape 
my $page = $pdf->page();
my $font = $pdf->corefont('helvetica');

my $gfx = $page->gfx();
$gfx->move(600,595);$gfx->vline;
$gfx->move(200,595);$gfx->vline;
$gfx->stroke;

my $content = $page->text();
$content->font($font,24);

my $y = 500;
for my $text (1,1.2,1.23,12.34,123.45,12345.67,123456.78){
  my $len = length $text;
  my $width = $content->advancewidth($text);

  $content->translate(200,$y);
  $content->text("$text ($len)($width) left align");
  $y -= 30;;
  $content->translate(600,$y);  
  $content->text_right("right align $text");
  $y -= 30;;
}
$pdf->saveas();

[download]
poj

In reply to Re: Dynamic text (amount in decimal) not aligned on PDF by poj
in thread Dynamic text (amount in decimal) not aligned on PDF by osexplorer

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