Trying to figure out how much to load on Oyster card.
Arriving in London Sunday morning, leaving Tuesday at 1 p.m. Will also use card to travel from King's Cross to Heathrow a week later. We'll probably use the bus and Tube a lot Sunday and Monday. How much should we load on the card to cover this usage? (Somewhere at some point in my research I found a table showing what the maximum would be in zones 1-2 for a day, but of course I failed to bookmark that page and now can't find it.)
After we return to LHR using the card, can we get a refund there for the deposit and unused portion?
It's been many, many years since I have been to London and I feel like a complete newbie here.
Always grateful for helpful Fodorites.

The cap for zones 1-2 is £6.80. A single bus ride is £1.50 and a single tube ride within zone 1 is £2.40
Single ride from zone 1 to 6 (LHR) is £5.10 peak, £3.10 off peak
The cap for zones 1-6 is £12.50

Estimate how many rides you think you'll take and calculate the amount to load up. Since I think you load up in increments of £5, you will probably have money left over and you can get a refund at the machines for any leftover money + your deposit. But be prepared to receive that as coins.

I gave up trying to calculate to the final decimal place the best amount and have come to rely on the advice of the agent at the window. Just tell him or her what you plan to do over what days and s/he will recommend the best way to go.

>>have come to rely on the advice of the agent at the window. <<

That used to be my fall back position . . . however, now most stations don't have window agents. There is usually someone there to help at the machines though.

But it really isn't that big a deal -- make a conservative guesstimate of what you'll need, and you can alway top up if needed.

Thanks for the numbers, lolfn. They will help us make a sensible guesstimate as janisj suggests.

By the way, I just came across the web page I was looking for:
https://www.toptiplondon.com/transpo...s/oyster-card/

Dead easy to reload it if it's getting low - in fact it won't let you use it if it won't cover the cost of the most expensive journey you can do, as I discovered one day when all I wanted to do was to go one stop on the tube. But topping it up meant I'd got credit for my next journey so it didn't matter.

The authority on fares is London Transport. Start here: https://tfl.gov.uk/fares-and-payments/fares

There is a new hopper fare for the bus/tram. WIth-in 1 hour of first touch-in on bus, you can use other bus/tram routes without paying another £1.50. If you download the TFL app, you can top-up your cards, too

" After we return to LHR using the card, can we get a refund there for the deposit and unused portion?"

If you have the card over 48 hours, yes.