You can edit a Sim you've already created by opening them in Create a Sim mode, even after they're living in a household

The fastest way to change a Sim's appearance, traits, or name is to enter Create a Sim (CAS) from the household screen. Open the household where your Sim lives, click on the Sim you want to edit, and select "Edit Sim" from the menu that appears. The game will load that Sim into the full Create a Sim interface, where you can change almost everything about them except their age stage — you cannot age a Sim up or down through editing.

Some changes take effect immediately when you save and return to the household. Others, like trait changes, require you to save the household first. The game will tell you if a change needs a save before it shows up in gameplay.

Key Takeaways

  • Open any household, click the Sim you want to change, and select "Edit Sim" to open them in Create a Sim mode.
  • You can change appearance, name, traits, aspirations, and skills, but not age stage or the Sim's birthday month and day.
  • Appearance changes show up immediately; trait and aspiration changes usually require saving the household first.
  • If you cannot find "Edit Sim" in the menu, make sure you are on the household screen, not the main game menu.

What you can and cannot change about an existing Sim

The Create a Sim interface lets you modify a Sim's physical appearance completely — skin tone, body shape, facial features, hairstyle, clothing, and makeup all work the same way as when you first created them. You can also change their name, gender presentation, pronouns, traits, aspirations, and skills. If your Sim has learned cooking or fitness or any other skill, you can raise or lower those numbers.

You cannot change a Sim's age stage (baby, toddler, child, teen, young adult, adult, elder) through editing. If you need to age a Sim, you must use a birthday cake or birthday party, or use mods or cheats. You also cannot change the specific day and month of their birthday — only the year, which changes their age stage. Some mods remove this restriction, but the base game enforces it.

Editing appearance without losing gameplay progress

When you edit a Sim's appearance — changing their clothes, hair, body shape, or facial features — those changes appear in the game world as soon as you save and return to the household. The Sim's relationships, skills, job progress, and inventory all stay exactly as they were. You are only changing how they look, not anything about their life.

This is useful if you want to give a Sim a makeover, fix a look you regret, or match them to a different aesthetic. You can do this as many times as you want without affecting their gameplay at all.

Changing traits and aspirations mid-game

You can add, remove, or swap a Sim's traits through editing, even if they are already an adult with a job and relationships. When you change a trait, save the household and return to the game — the trait takes effect on the next action the Sim performs. If you remove a trait that was tied to a specific behavior (like the Gloomy trait making them sad more often), that behavior stops immediately.

Aspirations work the same way. You can change a Sim's aspiration at any point, and their progress toward the old aspiration is lost — the new aspiration starts from zero. This is useful if you realize a Sim's current aspiration does not fit their playstyle, or if you want to pursue a different reward.

Fixing mistakes in a Sim's setup

If you created a Sim with the wrong name, wrong pronouns, or traits that do not match how you want to play them, editing is faster than starting over. Open the household, edit the Sim, make your changes, and save. You keep all their progress, relationships, and possessions.

Common fixes include changing a Sim's name if you misspelled it, adjusting pronouns if you want to change how the game refers to them, swapping traits if you picked ones that conflict with your gameplay goals, or changing aspirations if the current one is not working out. None of these changes affect the Sim's relationships or career progress.

Using mods to expand what you can edit

The base game prevents you from changing a Sim's age stage or their birthday month and day through editing. Several mods remove these restrictions. UI Cheats Extension and Mod Constructor both allow age changes through editing, though they require you to install them first and may need updates when the game patches.

Before installing any mod, check that it is designed for your game version and that you trust the creator. Mods can conflict with each other or break when the game updates. If you use mods and something stops working after a patch, disable them one at a time to find which one is causing the problem.

Frequently Asked Questions

Can I edit a Sim who is currently playing in a lot?

No. You must pause the game, go to the household screen, and then edit the Sim. You cannot edit a Sim while they are actively in a lot. If you try to edit from the main menu instead of the household screen, the "Edit Sim" option will not appear.

If I change a Sim's traits, do their relationships change?

No. Relationships stay the same. If you remove a trait that made them incompatible with another Sim, their relationship score does not automatically improve — it just stops getting worse from that trait conflict going forward.

What happens if I change a Sim's aspiration while they are working toward a reward?

All progress toward the old aspiration is lost, and the new aspiration starts at zero. You do not get the reward points back. Only change aspirations if you are sure you want to abandon the current one.

Can I change a Sim's skills through editing?

Yes. You can raise or lower any skill level — cooking, fitness, programming, anything your Sim has learned. This is useful if you want to reset a skill or give a Sim a head start in something new.