What is a donation carryforward?

Donations and, if applicable, membership fees to promote tax-privileged purposes can be deducted as special expenses up to 20 percent of the total income. If your donation exceeds this maximum amount, the excess amount is carried forward to the next year and considered within the maximum amount. This is known as a donation carryforward. The donation carryforward is unlimited in time and continues until the entire donation amount has been offset.

The tax office issues you with an assessment notice each year for the amount not yet taken into account.