Confusion about counting incubation days

[HeidiGetsChicks]

Someone on here mentioned that if I put the eggs in the incubator on a Tuesday at 5pm, then day 21 of incubation is 3 Tuesdays later.

I thought day 1 is counted 24 hours after first placing the eggs in the incubator? So that if I put them in on a Tuesday at 5pm then day 1 is complete the next day on Wednesday at 5pm?

I'm still new to this and counted incorrectly my first hatch because I counted the day I put them in as day 1. So this time I didn't and seems I did lockdown too late because a chick had already pipped internally. It's driving me a little bonkers that I cannot find clarity on counting days.

 

[SilverBirds]

You are right. Day 1 is 24 hours after the eggs have been set.

 

[Hedgeland Farms]

I believe that is correct.
Say you set Tuesday the 9th at 5pm. Then Wednesday (the 10th at 5pm) would be day 1. Count 21 days...leaves you on the 30th...which is a Tuesday ...likely to hatch that evening into the next day I would guess...
But I don't really know as I am just getting into incubating

 

[HeidiGetsChicks]

Okay I think I see my mistake.

I was counting weeks instead of days.

So if Wednesday is day 1, then I counted the next Wednesday as day 7.

When in fact the next Wednesday is day 8.

I had to physically count the days to convince myself of this.

 

[Hedgeland Farms]

Okay I think I see my mistake.

I was counting weeks instead of days.

So if Wednesday is day 1, then I counted the next Wednesday as day 7.

When in fact the next Wednesday is day 8.

I had to physically count the days to convince myself of this.

...same....
It's how I figured out my hatch day lol