To determine ages of individual (field) stars, composition, mass and distance should be known accurately, which is usually not the case. An alternative way is to use turn-off colours of field star populations. This method led in the past to ages significantly higher than those of globular clusters of the same metallicity. We show that colour-based relative ages between the field and cluster population indicate that they have similar if not equal ages. First steps using large samples of stars from SDSS are presented.