[bookie]

I'd like to use a Kelly criteria calculator that will allow me to see how fast a bankroll deteriorates when over-betting an edge.

There are a ton of them online, many seem to be copies of the one SBR put up first, but none that I have found do anything but calculate the optimal fraction first and then kick out the bankroll growth over X plays.

If you know of one that's more flexible I'd appreciate a link.

[HeeeHAWWWW]

Perhaps it's not what you're asking, but you can see the effect of overbetting in the SBR calc - just set Kelly multiplier to 1.5, 2.0 etc.

There's a fairly brutal falloff: betting at 1.5xKelly is the same EG as 0.5xKelly (but with wildly more variance), but betting 2.0x has an EG of ..... zero :-)

Edit: added a nice chart visualising this from https://www.drbobsports.com/essays.cfm?p=5:

[bookie]

When fooling with the multiplier the median bankroll will decline (show a result less than 100%), but I couldn't get the expected bankroll to do so. So I didn't know whether to trust those results.

[HeeeHAWWWW]

When fooling with the multiplier the median bankroll will decline (show a result less than 100%), but I couldn't get the expected bankroll to do so. So I didn't know whether to trust those results.

Looks ok to me - if I'm reading it right, the one labelled "expected bankroll" is a mean of outcomes, so it's always going to be a lot higher than the median (because the mean includes a small number of outcomes where the bankroll skyrockets, skewing the average upwards).

[bookie]

The difference confuses me. I thought that in a progression of bets using a fixed percentage the bankroll would be the same no matter what order the bets won or lost--just like if you multiply numbers together it doesn't matter what order.

I guess I don't know what the different outcomes you refer to (and are on the calculator) could mean if it's not the order of wins in losses for a specified series and strike rate.