Gestational sac sizes and ages

[damprye]

When you had your first ultrasound for each bub, how far along were you and what were the measurement
I need to go look up the others but my latest one I calculated at about 6w4d but haven't been told age via u/s as we weren't there to do a dating scan, sac measured 5x3x5mm giving a 4.3mm mean sac size. I know that with every pregnancy early on, I've measured roughly 2 weeks behind and am guessing that it'd date as around 4w5d but was just wondering about others experiences

[LysnDan]

At 4w5d gestation with my DD, sac size was 4.0x4.3x5.3mm.