My child is bigfoot

Nathan prepares to turn 3 this month and I realized it was time to get his summer sandals. I'm still not entirely sure how children's shoe sizes work so I assume this is still in toddler but Nathan is now a size 12. I think after 13 toddler he moves to 'big kid' sizes. His regular clothing is completely in boys size small (or 6/7) now. No more toddler for this little guy. I haven't measured his height lately but last that I did in February he was nearing 3 foot 5 and is 45 pounds. Man I have a big kiddo! Now if I can just get him to sleep more......