Printed Circuits should have their construction thickness stated including Soldermask and additional plating, which will typically add another 0.10mm ( 100microns) to the bonded pcb.
A PCB is made of Prepregs and Cores
Prepregs come in the following main styles
106 – Nominal Pressed thickness = 50um
1080 – Nominal Pressed thickness = 66um
2116 – Nominal Pressed thickness = 110um
7628 – Nominal Pressed thickness = 180um
7630 – Nominal Pressed thickness = 200um
The Core thickness stated does not include the copper weight ( it is the Dielectric)
Cores come in thicknesses from 0.05mm to 1.20mm ( Rigid FR4 can also be used as cores on thicker constructions, however Rigid FR4 thickness includes the copper thickness), and is available from 18um to 210um, 1/2oz to 6oz.
This is then build together as shown to make the board in the required thickness
Please note that the copper on the layers affect the final thickness, for instance if all layers were planes, the board would be thicker as there is less for the prepreg to encapsulate.
If the layers were all sparse signals the pressed board would be thinner as the resin from the prepreg try’s to encapsulate the tracking, please note if there is sparse tracking, consider using supplementary patterns, see DFM section.