Even small charities can have big complexities when it comes to choosing and using accounting systems.
There are two issues in particular which can be hard for charities to deal with on many accounting systems. The first is VAT partial exemption. Charities may have a mix of exempt income (grants, donations) and taxable income (eg selling goods or running a cafe). This means that they cannot reclaim all of their VAT and have to do “partial exemption” calculations.