If you used a monthly parking permit please divide this cost by 20.
For example driving to a train station, before getting the train to work.
For example, after-work drinks, gym memberships, shopping.
Increase in energy spend
While charging your laptop for 8 hours a day isn't going to break the bank, you will see an increase in your energy costs while working from home.
Running the heating, leaving lights on and cooking the extra home-made meal will add a few pounds to your energy bill PER DAY.