Minecraft Portal Calculator

Click here to try out an update to the portal calculator. It includes an experimental parser for extracting XYZ from a string like the one produced by F3+I. Enjoy!

The game minecraft is seriously fun! When you have played long enough to be at a stage where you are building nether portals you can use this quick calculator to find where to build your return gate for it to be connected as a pair between the nether and the overworld.

Nether portals make traveling across the overworld much faster, but if you are playing in a world with other players who build gates it's not uncommon to materialize in an unexpected location when stepping through a nether portal.

Wrong Return Gate

I built a portal from my home at X,Y,Z and stepped through only to land in a portal room built by someone else in the nether. This was fine, but when I walked back through it, my X and Z were nowhere near the gate I entered from--instead I came back to their homestead and then had to scramble across the landscape at night, a long, long way trying to avoid mobs and hazards; it was a frightening journey.

As it happens, what I needed to do was determine my X,Y,Z coordinates before stepping through the original portal. If I had carried at least ten obsidian and flint and steel with me, on the nether-side of the gate, I could explore to X/8, Y, Z/8 and then build a return portal at that location. I could then activate it with my flint and steel and with any luck it would attach to the gate I came in from. I know I know, this isn't new knowledge it's just that I had not seen the math clearly articulated on pages found by searching at the time.

Calculator to translate between the overworld and the nether

It seemed like a quick calculator to translate coordinates based on which side of the gate I was plugging in might be helpful and could help provide a mathematical proof while performing the calculations mentally takes hold. As a web developer, I thought building the calculator using JavaScript and HTML might be a fun little project! (Hooray, arithmetic and basic algebra really is useful after all. ;-)

Suggested steps:

Collect 20 obsidian blocks and create a flint and steel using the recipe.
Go to the place you want your return portal to appear.
Hit F3 while in the game and collect your X, Y, and Z coordinates. (Hint: See the F3+I Parser notes for more.)
Plug them into the calculator (if you can have a browser open in the background it's quick to switch between the browser and the game without needing to disconnect).
Note: you can either plug the coordinates in one at a time -or- as a comma separated list (for example 100,66,300). If you only provide two coordinates (such as 100,300) they'll be used to populate X and Z.
Use the first 10 obsidian to build a nether portal (economical version) and step into the nether (cautiously).
Explore to the coordinates from the calculator. Again, be careful, the nether is more challenging to navigate than the overworld.
Some specific cautions:
- I still get caught by very fast moving lava when tunneling in the nether.
- Mining related falls are really easy if you are moving quickly.
- With the 1.16 release there are a lot more hostile creatures to threaten you while wandering!
- G-H-A-S-T fireballs will wreck your day! (Bring cobblestone to reinforce any bridgework you do...those flying marshmellows aren't friendly!)
- Did I say LAVA? (There's an enormous amount of lava. If you aren't careful not only will it burn you up, it'll destroy your drop after you've burned up! CAREFUL!)
- Etc, etc, etc...there's so much to be afraid of in the nether. Just be careful!
Build your return portal at the coordinates, step through and with any luck you'll be back at the portal you built initially.

Huh, it didn't work?! I believe there are some rare cases in which the gates might not hook up like you expect. If that happens, you may need to do more research to determine what's going wrong. I've had this happen very infrequently, but occasionally it does and I've stepped out of a new gate in a dark ravine or out in the countryside. It seems like it's always above or below the gate I was trying to come back through. (Along the Y axis, though X and Z can be off too. In fact in my case the problem has always been that I was slightly off on my X and Z when building the return gate--and rechecking my coordinates and fixing where the return gate is has solved the problem for me.) However, stepping through a gate into unexpected territory is obviously jarring; So, be prepared. It's always a good idea to carry torches, tools, and supplies.

Thanks for your visit, I hope this helps you. If you find any errors or have suggestions, please let me know. Also, if you are learning web development or wanted to build your own calculator view the source to see how this one works.

Best wishes!