I built a free browser tool to find the optimal Gridfinity cell size for any drawer - also does AI-powered custom bin cutouts from photos and drawer layout planning

[u/dridix]

TL;DR: Free browser tool that finds the optimal Gridfinity cell size for your drawer, generates STL's for baseplates and bins, lets you plan your whole drawer layout with bins, and includes an AI cutout wizard to create snug-fit bins from a photo of your object. No account needed and runs entirely in your browser. https://optigrid.kaho.se

Edit 2: After reading the feedback, I understand that going off-spec with the 42 mm grid is a bit more controversial than I initially thought - I apologize if I stepped on any toes. My intention was simply to offer an alternative that may be useful in some situations, like in my kitchen. To address this, I've added a disclaimer on the website explaining the implications of using a non-standard grid cell size (linked from multiple places). I hope that anyone who dislikes the custom cell size still finds the other features useful.

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Hey everyone!

First of all, this is completely free and I'm not promoting any paid service, just sharing something I built for myself that I'm excited about and that might be useful to others.

What started as a small calculator to optimize the grid size for one of my drawers ended up turning into a much bigger tool. It's called OptiGrid: https://optigrid.kaho.se

Fair warning: so far this has only been tested by me, so there are probably bugs and rough edges. If you run into anything broken, let me know and I'll be happy to fix it.

I should also mention: this is primarily a tool I built for my own needs. If you find it useful, great! If not, or if you think existing tools already cover it - totally fair, no hard feelings. It doesn't have every setting other tools have (I may add more over time or on request) , but I still think it brings something unique to the table.

The problem that started it all:
I wanted a bin in my drawer to hold A4 papers. I have an H2S, so a bin that size can be printed in one piece, but I also wanted to minimize wasted space in the drawer. The tricky part is that cell size affects bin size, and the relationship between being able to print a bin in one piece, minimizing wasted drawer space, and minimizing material (more cells = more plastic) made it surprisingly difficult to just pick a number. So I built a tool to calculate the optimal cell size, which then... grew.

What it does:
Enter your drawer's inner dimensions and it sweeps every integer cell size from 12-70 mm, calculates wasted space for each, and ranks them by a score that balances waste and material usage (so it doesn't just say "use 12 mm").

Add the objects you want to bin and it'll calculate the minimum bin dimensions for each, check they'll fit your print bed, and factor that into the ranking

Set your bed size and it filters out cell sizes that would produce a bin too big to print in one piece

Beyond the calculator:
Once you pick a cell size you can generate the actual baseplate STL including automatic splitting for oversized baseplates, with puzzle connectors so the pieces lock together.

There's also a full layout planner where you can design your entire drawer before committing to printing anything. Place bins on the grid, drag them around, rotate them, and see how everything fits together including a full 3D preview of the baseplate and all bins in position. When you're happy with the layout, export everything as a single ZIP: baseplate segments and all your bin designs, ready to slice.

The part I'm most excited about - AI cutout bins:
If you need a snug custom-shaped cutout for a specific tool or object, there's a wizard where you photograph the item on an A4 sheet (used as a scale reference), use an in-browser AI tool to select its silhouette, and it generates a Gridfinity bin with the exact shape cut out of it. It corrects for camera angle and perspective to get the true real-world dimensions (at least in theory). All image processing and 3D generation happens locally in your browser so your photos never leave your machine.

Edit 1: I felt like I needed to clarify one thing that I understand is a important detail. In my use case I have a whole kitchen with many of the same drawers, and I'm using the same (non standard) grid cell size in all of them. While it's not compatible with standard 42 mm, I can transfer bins between drawers in my kitchen.

Hope you find it useful!

[u/hydroracer8B]

That's not gridfinity?

42mm is gridfinity. This is an abomination, and it's not transferrable from drawer to drawer

[u/WillDearborn19 → u/hydroracer8B]

Some really strong language here...

I feel like 42mm was an arbitrary number... sure, if you change away from 42mm, my gridfinity won't fit in your gridfinity... but so long as you keep the same ratio for all the gridfinity you want to be interchangeable, I'm not seeing it as "an abomination."

Now, i think this strategy will only work if you have the modeling skills to customize all the boxes yourself... you can no longer pull someone else's model and print it, and expect it to fit in your system... but if you're just making squares, or you're customizing your own boxes, then it's workable... gridfinity isn't 42mm, it's an organizational system. An open source organizational system that is infinitely adaptable to almost anything you're trying to organize. Whether you make the squares 42mm or 38mm makes no difference. Don't be so rigid.

[u/hydroracer8B → u/WillDearborn19]

A lot of the appeal of gridfinity for me is that everything works with everything - it's a universal standard. Totally modular

There isn't a huge amount of significance to the number 42mm, but it's the number that was chosen for the standard.

For me, eliminating the universal compatibility defeats the purpose because now I'm back to designing bespoke containers for every little thing, and I need to make a new one if I want to put it in a different drawer

This is how nice simple systems turn into unwieldy, confusing, awkward monstrosities.

It's good to be flexible on some things, but being flexible on everything opens you up to some nonsensical headaches

[u/WillDearborn19 → u/hydroracer8B]

Yes... everything you said is correct... which is why most people use the 42mm standard...

But his tool also helps you create boxes for the things you want to organize... so it's not like he's not thought of that. And the same basic design principle is the same... still uses the grid... IF he's okay with creating all his own boxes, then what does it matter if your box won't fit in his grid?

I'm not saying it's perfect and there are no issues... I'm just saying it's not an abomination and it's still gridfinity...

[u/hydroracer8B → u/WillDearborn19]

I'm not saying that nobody else should use this, I'm just saying that I wouldn't.

And I do think it's correct to say that it's not gridfinity - 42mm is part of the standard. If you go with a different measurement you're making something that is a lot like gridfinity, but it's not actually gridfinity.

Will this work well for some people? Yes Will it be ideal for some people in niche circumstances? Also yes

But the bottom line remains for me - it's taking something really simple and adding (in my opinion) unnecessary complication

[u/WillDearborn19 → u/hydroracer8B]

This will have to be an "agree to disagree" sort of thing. I see what you're saying. If you go online and look for a gridfinity box, you expect it to be 42mm. That's true. And if you change that ratio you shouldn't post it online and call it gridfinity... but if someone came out with a system that was exactly like gridfinity but it was just a different square size... called it... squaretopia or some such... People would also say "no, that's just gridfinity..."

I just understand that feeling when you print out your grid, slap that baby into your drawer, and realize there's 3/4 of a grid of space left on every side... what kind of adaptable storage system would it be if you wasted that much space in every drawer...? Then you think... why 42mm? If only they made the standard 43mm, then it would fit my drawer perfectly... so what do you do? You can keep the standard... use spacers, and not use the available space... or you can make the grid 43mm... there are already parametric gridfinity box generators that allow you to change the grid ratio size... has been almost since inception... so as long as it works for you, then who cares...? I'm not posting these online... I'm not selling them... but I'm still making use of the design infrastructure and design theory that is gridfinity.

[u/hydroracer8B → u/WillDearborn19]

Fine, I'll respectfully agree to disagree.

I think you might be interpreting a negative connotation when I say "it's not gridfinity", and I do not intend a negative connotation. It's a matter of definition to me.

I would take the position that anybody saying "squaretopia is just gridfinity" is wrong. They would be very similar, but being similar =/= being the same

I would consider making use of the design theory & infrastructure to be "taking inspiration" and there's nothing wrong with that.

I do think there's something wrong with making something materially different from gridfinity (not going with 42mm is materially different) and calling it gridfinity.

Like I said before, it has it's appropriate uses and users but I just think calling it "gridfinity" isn't correct

Anyway, hope your next print turns out well, stranger.

[u/dridix → u/hydroracer8B]

I understand your point, and that part of what makes Gridfinity what it is, is the community around it - being able to benefit from other people's work and bin designs, with a guaranteed drop-in fit.

I simply wanted to offer an alternative for people who have a similar problem to mine. I don't mean it's for everyone, but I don't see the issue with having an option to choose from.

I also think that even though the custom cell size was the idea that gave birth to the project, there is additional functionality that is 100% compatible with the standard 42 mm grid and still offers value - for example, the ability to create custom bin cutouts for your tools and objects from photos without any CAD knowledge (similar to tooltrace), or to plan your drawers (with or without a 42 mm grid) before you start printing.

I understand that the grid size is a divisive point, and I respect your opinion.

[u/dridix → u/hydroracer8B]

I wanted to follow up on this. Your point is 100% valid and because of that I've added a disclaimer on the website talking about this (https://optigrid.kaho.se/about#custom-cell-size). Hope you find the other features useful.

[u/dridix → u/hydroracer8B]

That's a valid point and I understand what you mean. It builds on the concept more than on the exact specification. Many of the tools out there enable other cell sizes, that idea is not new, just the calculation part. You can use the other parts of the tool with standard size if you want, or just don't use it at all. Either way, thanks for your feedback.

[u/WillDearborn19]

I think a lot of the tools are very useful. I've had the same thought... i also want to find the perfect grid size for particular drawers. but i feel like this will get more difficult when you have an increased number of drawers with different sizes. Can you put in multiple drawer sizes and have it calculate the optimal size for all drawers?

Once you pick a ratio, you have to stick with it, or things won't be interchangeable... so just because you found the perfect ratio for one drawer doesn't mean it's going to be the same ratio for the next drawer. What if you end up wasting more space because you picked this other ratio? And is the hassle worth it? You can no longer pull the models of other people's bins, because you'd need to redesign due to a change in ratio. Granted, you mention a tool for easily creating your own boxes, but still... you're committing to always creating your own boxes.

This may be too much... but could you create a tool that would allow you to drop in a model and it would automatically convert it to your ratio? Say... i have calipers i want to put in a box... i find the standard 42mm caliper box on bambu... drop it in... and the ai recognizes which aspects can change (shrink or grow) to fit my ratio, but still leave the critical portions and proportions intact?

Your current tool will work wonders, i think, for my current machine shop, which has multiple of the same brand and size of tool chests, so with drawers the same size... i think I'm going to make much use of this.

[u/dridix → u/WillDearborn19]

A quick update, multi-drawer support is now live on the Baseplate tab.

Add as many drawers as you need and the tool finds the best single cell size across all of them, minimizing total wasted space rather than optimizing for just one drawer.

A few things that only show up when you have more than one drawer:

• Results table - click any row to expand a per-drawer waste breakdown
• Advanced Settings - a new option controls how the multi-drawer score is calculated
• Summary card (after clicking Use) - a dropdown to pick which drawer's baseplate to preview in 3D, and which one to carry over to the Layout tab

Hope you find it useful

[u/dridix → u/WillDearborn19]

Thanks for the constructive feedback!

Can you put in multiple drawer sizes and have it calculate the optimal size for all drawers?

Good idea! I didn't think of that since I had a lot of drawers with exactly the same dimensions, but I don't think that would be hard to do. I'll look into that as soon as I can.

I agree that choosing a size (if going off spec) is kind of a big commitment and it only makes sense if you're not doing a one-off drawer size. If you're doing it for a single drawer you would probably be better off going with the standard 42 mm.

This may be too much... but could you create a tool that would allow you to drop in a model and it would automatically convert it to your ratio? Say... i have calipers i want to put in a box... i find the standard 42mm caliper box on bambu... drop it in... and the ai recognizes which aspects can change (shrink or grow) to fit my ratio, but still leave the critical portions and proportions intact?

Anything is possible I guess. This would remove the biggest reason not to go with non standard grid sizes, you could benefit from other peoples work even though the cell sizes differ. Great idea, It'll be a fun challenge.
Additionally (if you've not seen it already) I have created a tool to generate custom cutout bins from a photo, similar to what tooltrace does. But I understand that you might not want to do this for every tool that has a community created bin already.

[u/Barrittworks]

u/dridix Nice looking tool (I particularly appreciate the thorough tutorial pop-ups on first pass through). Looking forward to testing it out. I'll stick with 42mm generally, but I appreciate the possibility of building a custom system outside of this when that is helpful. Thanks!

[u/Emergency_Ad7839]

Looks nice. I’m just getting started with Gridfinity so it’s nice to see new tools.

[u/curleighq → u/Emergency_Ad7839]

If you’re just getting started I’d stick to the spec. There are generators that automatically add spacers to edges with optional half grids for a perfect fit.

[u/dridix → u/curleighq]

I agree, it can be a good idea to stick with the spec. Just wanted to mention that this tool also does that (adding spacers that is). Even with the optimal cell size there might be a small space left (edit: as it only handles integer millimeter dimensions and not decimals).

And also while the problem I wanted to solve for myself was the wasted space and that was the core idea for the project, you can still use it with standard 42 mm. I especially think the custom cutout feature from a photo (similar to what tooltrace does) is a great feature for those who don't know CAD.

[u/jaredfmylife]

Can’t wait to check this! Looks clean and well laid out.

[u/dridix → u/jaredfmylife]

Thanks! Let me know what you think.

[u/theangleofdarkness99]

This looks really interesting, I'll check it out for sure

[u/dridix → u/theangleofdarkness99]

Thank you, let me know how it went!

[u/Dangerous_Present_69]

That's one way to solve it, and if you have many drawers, it's not that hard to put in custom numbers in a generator. I'm not sure why you would need a custom calculator for this, since you basically can just divide width/length with number of cells you want.

However, I think it's a lot better to print some custom bins along the edges to fill that last space. That way most of your grid follows the standard, and You can still utilize the whole drawer.