Weekly vs monthly travelcards, London

[Jonny69]

Ugh, I'm struggling with the TFL website... someone please explain...

I'm currently getting a weekly travelcard, commuting for a week, then work from home one day and get another weekly travelcard.

So in a long 31 day month I buy 4 weekly travelcards and roll a day over to the next month, shorter months I roll more days over to the next month.

How do monthly travelcards work with the varying month length? Are they pro-rated or do they just work out more expensive on a shorter month? Or do you get 31 days travel whatever the length of the month?

I'm trying to work out if it would work out more expensive for me to get a monthly, based on working from home one day a week which I don't currently pay to travel on.