Simulations at fixed topology: fixed topology versus ordinary finite volume corrections

Lattice QCD simulations tend to get stuck in a single topological sector at fine lattice spacing, or when using chirally symmetric quarks. In such cases computed observables differ from their full QCD counterparts by finite volume corrections, which need to be understood on a quantitative level. We extend a known relation from the literature between hadron masses at fixed and at unfixed topology by incorporating in addition to topological finite volume effects, also ordinary finite volume effects. We present numerical results for SU(2) Yang-Mills theory.