Why do the 2 bitcoin halving clocks have dates that are 3 weeks different?

[jasonjm]

Which is the correct date?

[Amph]

you mean this http://www.bitcoinblockhalf.com/ and this http://bitcoinclock.com/?

it is probably because of the diff retarget(due to some time the possibility of more coins are mined per day) that can accelerate the halving

and keep in mind that these are only estimations...

[jasonjm]

Yes exactly

But with the date getting close one of those sites has terrible math

3 weeks is way too large a margin

[RyNinDaCleM]

I would imagine that they both get more accurate as the time approaches. bitcoinclock.com has been around since the first halving and was right on at the time of halving. I would also guess they are closer than the other right now considering 20-7-2016 was the date a few weeks ago and I doubt we've shaved a whole month off already. One other thing that may influence the bitcoinblockhalf site is they may take a more extreme estimate of diff increases assumed over the coming months rather than the current increase with a worst case scenario that blocks will continue to be found at the predetermined rate of 6/hr and not try to guesstimate what increases will happen in the future.

tldr; as halving approaches, they should both be very close to one another so don't worry about today's premature estimated date

[croato]

It is because block time. Average block time is around 10min (8min and 40ishs sec i think) so you can only count approximate time till next halving. We know exactly after which block miners prize will be halved but not exact time when that will happen.

[Nimbulan]

Maybe because miners mined diffrent ammount of blocks, so time to halving will be diffrent from what it was 4 years ago

[European Central Bank]

One site is paying attention and the other ain't? Maybe the other one isn't being maintained right. I'll go for the more dynamic one.

[BitcoinHodler]

One site is paying attention and the other ain't? Maybe the other one isn't being maintained right. I'll go for the more dynamic one.

nah, i think they are just using different code to calculate the estimated time for the halving happening. and since there is not correct answer both can have a shot at being the right guess.

[European Central Bank]

But that's a crazy big gap. One or the other isn't paying attention or doing their math right. If they both were then they'd be a lot closer together surely.

[takingthis4]

i think one of sites just forgot to update to correct date of halving, or miners started to mine more bitcoins(faster) and one site didn't notice that, so they forgot it