The scale of synthesis (25 nmol, 50 nmol, 200 nmol, 1 µmol, or 10 µmol) refers to the starting scale and not the guaranteed final amount. Oligonucleotide length, sequence, GC content, and coupling efficiencies can vary the oligo yield post-synthesis. In addition, further losses occur during processing, transfer of material, and quality control. Invitrogen guarantees the total yield of oligonucleotide as a minimum number of OD units. Purification by HPLC, PAGE, and Cartridge will also affect final oligo yield.

The table below shows minimum guarantee yields (OD260). Please note that OD guarantee is valid for unmodified oligos 20 to 100 bases in length. Yields for oligos under 20 bases are not guaranteed and in general they are about half of the values as shown in the table below. 
Number of bases Synthesis scale Purification
Desalted (OD) Cartridge (OD) HPLC (OD) PAGE (OD)
>20 25 nmol 2 n/a n/a n/a
50 nmol 4 2 1 0.5
200 nmol 16 10 3 1
1 μmole 50 25 5 5
10 μmole 500 n/a 15 50