System for filling containers, comprising: an empty container feeder via which the system can be fed with crates of empty containers, preferably on pallets, in order to refill said containers, an unpacker which removes the containers from the crates, at least one treatment station (6, 7, 8) for the containers, in particular for cleaning and filling the containers, at least one treatment station, in particular a crate washer for the crates, a packer to which the treated containers and the empty crates can be fed for packing the containers into the crates, and a crate flow divider which can feed the empty crates to the packer or can discharge them from the system, characterised in that the system also comprises the following components: a first counting device (12a-d, 13) for determining the number of containers fed to the system, a second counting device (15a-e) for determining a number of crates directed to the packer, a calculating device which, based on signals from the first and the second counting device (12a-d, 13, 15a-e), can calculate how many crates still have to be fed for the determined number of fed containers, wherein the system is configured so that, when production is switched from first containers in first crates to the production of second containers in second crates, feeding of the second containers in the second crates starts when there are still first containers and first crates in the system. an empty container feeder via which the system can be fed with crates of empty containers, preferably on pallets, in order to refill said containers, an unpacker which removes the containers from the crates, at least one treatment station (6, 7, 8) for the containers, in particular for cleaning and filling the containers, at least one treatment station, in particular a crate washer for the crates, a packer to which the treated containers and the empty crates can be fed for packing the containers into the crates, and a crate flow divider which can feed the empty crates to the packer or can discharge them from the system, characterised in that the system also comprises the following components: a first counting device (12a-d, 13) for determining the number of containers fed to the system, a second counting device (15a-e) for determining a number of crates directed to the packer, a calculating device which, based on signals from the first and the second counting device (12a-d, 13, 15a-e), can calculate how many crates still have to be fed for the determined number of fed containers, wherein the system is configured so that, when production is switched from first containers in first crates to the production of second containers in second crates, feeding of the second containers in the second crates starts when there are still first containers and first crates in the system. a first counting device (12a-d, 13) for determining the number of containers fed to the system, a second counting device (15a-e) for determining a number of crates directed to the packer, a calculating device which, based on signals from the first and the second counting device (12a-d, 13, 15a-e), can calculate how many crates still have to be fed for the determined number of fed containers, wherein the system is configured so that, when production is switched from first containers in first crates to the production of second containers in second crates, feeding of the second containers in the second crates starts when there are still first containers and first crates in the system.