# eli5 Why do house numbers skip digits?

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My brother lives at 35 Parson Lane, yet the next-door neighbor is at number 25. My last house was number 10, the next-door neighbor was at number 12. Why all the number skipping? Why not just go in numerical order starting with 1, then 2, etc.

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odd numbers on one side of the street even on the other,also they count lots ,so if you have 3 lots side by side with only one house it could be 6-7 numbers off to leave the room for when the other lots are developed.

There are two reasons that this can happen.

The first is that each house actually crosses multiple lots. The city might make the lots 30 feet wide, but if they each cross over 2 or 3 lots, they essentially eat up those numbers.

The other reason is for mail delivery. Especially if you have a community mailbox that is used for multiple streets, you might avoid having the same number in use on both of those streets, as that can create some mail problems. I personally run into this, as my house is number X, and on the neighboring street that uses the same community mailbox there is also number X. We get each others mail all the time.

And finally, the last little bit of odd vs even numbers. There are some parts of the world where this isn’t the case, especially with historical numbering. If someone is going down a street, this allows them to easily identify the side of the street they’ll find their destination on.

If you want the exact answer given to you contact your city engineer.

They could have laid out the lots based on a certain square footage and if a home was built across 3 plots then it can go with a certain number.

It could be that they were just going up by tens.

And as far as going numerical odds are on one side and evens are on the other. They do that for continuity. I.e. 100 block of main street.

It can also be percentage of the block…The corner house is 100, the one in the middle is 150, the one at the end is 198. When you build another house later you will have a number that fits.

Similarly, it could be distance in absolute numbers (e.g. yards). That gives you numbers in the ten thousands.

With both of these you know exactly where a number is.

My street’s numbers are all fucked up. My house number is 1658. My neighbor to the right is 238 and my neighbor to the left is 1660. No idea what caused it. A few houses past 238 it goes back into the 1600’s again. It’s super weird.

Maybe you would prefer like they do in other places?

Numbers run around the entire block consecutively on one side only.

Blocks are named after letters.

There are a whole different bunch of numbering systems used in different places. Some older places in the UK that still have original housing might simply have been numbered in the order they were built. This can lead to weird numbers. But it’s not that common. Much more common would be like 10 being next to 12. In the UK, we tend to have all the consecutive odd numbers on one side of the street and the even numbers on the other.
There may also be some gaps where the plot of land has another use. One of the streets I lived in had a bunch of short rows of 4 houses that ran parallel to each other. One row had 2, 4, 6, 8. The next was 12, 14, 16, 18. The reason is that there were a block of garages at the end of each row, so the garages counted as plot 10, 20, etc.
In the US, it’s more common to number each block, and then the houses within it. You can have the 100 block, where the houses count from 100 upwards. Say you only get to house 150, and then there’s a new block. The next block will start at 200, so 152-198 are missing.
Or, you could have a proportional system where 150 is halfway along the block and 198 is at the end. Here, the numbers will just jump up. But it means that if a plot gets split in two, it’s easier to give the new plot a number.

They don’t always…the house numbers on my street start at 1 on the left-hand side of the entrance and just increase sequentially from there until the house opposite that one is number 42. I guess that might be because I live on a close where there isn’t any practical way they could extend the road any further due to other thoroughfares.

I think this practice started in Philadelphia, the first planned city in the west. Each block got assigned 100 numbers, like 800-899. Even numbers on one side, odd numbers on the other. So you always know which side of the street you’re looking for. And it was systematized so if something is on a block between 7th and 8th streets, then its number will be between 700 and 799. So you always know approximately where a building will be just from hearing the numbers. Like 1500 Walnut street? Ok, south side of street, on the corner of 15th and Walnut, on the side between 15th and 16th. This scheme allowed for a lot more numbers (100) than there is space in one block to fit—50 numbers per side. But super convenient when not
Everyone has an infinite GPS map in their pocket. It also allows for more numbers if there’s expansion. Like change your building into 2 apartments and you can now have another street number. This led to people adopting a similar practice all over the country.

First, address numbers are odd on one side, even on the other (here in Chicago even are on North and West sides of streets, odd on South or East sides). This helps give context which side of street a building is on.

House numbering is determined on the local level and usually the range of address numbers extends from a single axis and get larger directional from there. Maybe it’s the center of the city, or the far SE point and from there numbers get larger as you get further. This way, the number gives context of location within the city. In the town I grew up, the houses on the southern border closest to the lakefront were smallest, and you’d see addresses like 2 or 10. As you headed west and north, numbers got bigger, into the 1000’s on the NW part of the town.

There may be reasons such as evenly spacing numbers within the address grid. If a section of road after one cross street starts with 100 addresses and the next cross street begins the 200 addresses, and the street between only has 10 houses, they want to evenly space them for better context — it’s more clear that 190 Reddit St is close to the second cross street vs. if the homes were 100 Reddit St, 102 Reddit St. up to 118 Reddit St. and then they jump to 200 Reddit St.

It also leaves room for adding homes, if for some reason there are infill lots that could be built upon, or homes get replaced with more dense housing, ie. tear down 3 cottages and build 6 townhouses.

As others have mentioned, you have odd numbers on one side of the road and even numbers on the other so that it’s easy for others (delivery people, visitors…) to tell which side of the road you’re on when they lok for your house.

Distance plays a role as well. I used to live on a rural dirt road with only about a dozen houses, yet my house number was >400 while my next-door neighbor was about 80 numbers lower.

That said, different places have different rules. My parents who live in a different town in that same county have a house number below 50 despite having more houses on their road. Their town still follows the even/odd system, but the progression is a bit different.

Rule 2.