We present an isochrone server for semi-empirical pre-main-sequence modelisochrones in the following systems: Johnson-Cousins, Sloan Digital Sky Survey,Two-Micron All-Sky Survey, Isaac Newton Telescope (INT) Wide-Field Camera, andINT Photometric H$\alpha$ Survey (IPHAS)/UV-Excess Survey (UVEX). The servercan be accessed via the Cluster Collaboration webpage{http://www.astro.ex.ac.uk/people/timn/isochrones/}. To achieve this we haveused the observed colours of member stars in young clusters withwell-established age, distance and reddening to create fiducial loci in thecolour-magnitude diagram. These empirical sequences have been used to quantifythe discrepancy between the models and data arising from uncertainties in boththe interior and atmospheric models, resulting in tables of semi-empiricalbolometric corrections (BCs) in the various photometric systems. The modelisochrones made available through the server are based on existing stellarinterior models coupled with our newly derived semi-empirical BCs. As part of this analysis we also present new cluster parameters for both thePleiades and Praesepe, yielding ages of $135^{+20}_{-11}$ and$665^{+14}_{-7}\,\rm{Myr}$ as well as distances of $132 \pm 2$ and $184 \pm2\,\rm{pc}$ respectively (statistical uncertainty only).
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