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We present non-local thermodynamic equilibrium (NLTE) line formationcalculations for Ca I and Ca II in B-F stars. The sign and the magnitude ofNLTE abundance corrections depend on line and stellar parameters. We determinecalcium abundances for nine stars with reliable stellar parameters. For allstars, where the lines of both species could be measured, the NLTE abundancesare found to be consistent within the error bars. We obtain consistent NLTEabundances from Ca II lines in the visible and near infra-red (IR, 8912-27,9890 A) spectrum range, in contrast with LTE, where the discrepancy between thetwo groups of lines ranges from -0.5 dex to 0.6 dex for different stars. OurNLTE method reproduces the Ca II 8912-27, 9890 A lines observed in emission inthe late B-type star HD 160762 with the classical plane-parallel and LTE modelatmosphere. NLTE abundance corrections for lines of Ca I and Ca II werecalculated in a grid of model atmospheres with 7000 K < Teff < 13000 K, 3.2 <log g < 5.0, -0.5 < [Fe/H] < 0.5, Vt = 2.0 km/s. Our NLTE results can beapplied for calcium NLTE abundance determination from Gaia spectra, given thataccurate continuum normalisation and proper treatment of the hydrogen Paschenlines are provided. The NLTE method can be useful to refine calciumunderabundances in Am stars and to provide accurate observational constraintson the models of diffusion.

A NLTE line formation for neutral and singly-ionised calcium in model atmospheres of B-F stars