NMR chemical shift prediction of carbonyl carbons in aldehydes/ketones

The chemical shifts of carbonyl carbons in aldehydes and ketones, as well as some carboxylic acid derivatives, can be estimated using substituent chemical shifts (SCS) for the substituents.
The SCS values used for the calculations are taken from [1].
Better estimations are available for the chemical shifts of carboxylic acids and esters and amides.

Literature

[1] "Parameter set for the prediction of the ¹³C-NMR chemical shifts of sp²- and sp-hybridized carbon atoms in organic compounds"
Pretsch E, Fürst A, Robien W Anal. Chim. Acta 248 (1991) 415-428