In The Sims 4, lot sizes are locked in place. You cannot stretch a lot or make it larger than what the game gives you. If your Sim wants a bigger home, the only real option is to move to a larger residential lot.
You can still play around with builds, though. Build Mode lets you place a big house on a smaller lot, but if parts hang over the edges, you will need to shift the building around and trim whatever does not fit.
The lot itself never changes size, only the house does. The same idea works the other way around.
If you move into a large lot with a small house, you can expand it as much as the space allows. If a large lot already has a house and no one lives there, you can bulldoze it and start from scratch.
The biggest lots in the game measure 64 by 64 tiles.
These are the largest spaces you can build on, and there are only a handful of them across different worlds. Some are residential, while others are parks or special lots.
List of 64×64 lots in The Sims 4:
- Windenberg: Dresden House and Von-Windenburg Estate (residential)
- Brindleton Bay: Hound’s Head (residential)
- Del Sol Valley: Chateau Peak (residential)
- San Myshuno: Myshuno Meadows (park lot)
- Selvadorada: Alam Museum of Archaeology (rental lot)
- San Sequoia: Celebration Center
- StrangerVille: The Lab
- Henford-on-Bagley: Olde Mill Hill
- Copperdale: Copperdale High School
- Chetsnut Ridge: Red Roan Field
- Ciudad Enamorada: Calle del Ensueño, Caminito del Deseo
- Ravenwood: Hay Hill Landing, Eternal Hollow
After those, the next biggest options are 50 by 50 lots, followed by 50 by 40 lots.
List of 50×50 lots in The Sims 4:
- Willow Creek: Oakenstead (residential) and Magnolia Blossom Park (park)
- Oasis Springs: Affluista Mansion (residential) and Desert Bloom Park (park)
- Granite Falls: Granite Falls Forest (rental lot)
- Magnolia Promenade: FutureSim Labs, and Willow Creek Hospital
- Sulani: Admiral’s Wreckage, and Saphire Shores
- Tartosa: Thebe Estate
- Chetsnut Ridge: Palomino Junction
- Ravenwood: The Marigold Chateau, Old Ravenwood Estate
List of 50×40 lots in The Sims 4:
- Newcrest: Twin Oracle Point
- Del Sol Valley: Vacuous Green, The Ward Den, and Bailey-Moon Manor
- San Sequoia: 7 Eucalyptus Lane, and Robls Point
- StrangerVille: Old Penelope
- Britchester: Laurel Library
- Henford-on-Bagley: 2 Olde Mill Lane, 3 Olde Mill Lane, Isle of Volpe Park
- Tartosa: Celebrazioni d’Amore, and La Coppia Serena
- Moonwood Mill: The Grimtooth Bar & Bunker
- Copperdale: Totter Park
Splitting and Merging Lots
You cannot split a lot into smaller pieces. Even if you build multiple houses on one big lot, the game still treats them as a single household. That means shared money and shared bills.
People often use this setup to create things like small house communities on very large lots. Keep in mind that a lot can only hold up to eight Sims at once.
You cannot merge lots or expand outward either. What you can do is save your current house to the library, then move your family to a bigger lot and place the house there. Sims can only own one home at a time, so moving always replaces the old one.
If you are looking specifically for a 50-by-50 lot, there are two residential choices. One sits in Willow Creek, is called Oakenstead, and already has an empty house you can demolish.
The other is the Affluista Mansion, located in Oasis Springs, and it starts out owned by the Landgrabs, so you will need to move them out first.
Owning more than one lot is usually not allowed. The only exception is running a business, which requires the Get To Work expansion.
Without that pack, your household sticks to one home, and upgrading your space means packing up and moving to a larger lot.
Happy Simming!