Brick by Brick runs fourteen free LEGO tools, and none of them asks you to sign in. Five help with the pieces and models you already have, six help you choose a set, two track a collection, and BlockTalk answers questions. This page says what each one does, what it needs from you and where its limits are, so you can go straight to the right one.
What is free and what is limited
Every tool is free and works without an account; the site does not offer new accounts. The calculators, planners and model tools have no limit at all. The AI features share one allowance of ten answers every 24 hours per visitor: BlockTalk, the AI Set Recommender, and the AI suggestions inside the comparison, value tracker, collection, display space and build time tools. The site earns from affiliate links when you buy through them, which is what keeps the tools free.
For the pieces you already own
Missing Piece Checker
Pick the set you are building. Before calling a piece missing, the checker walks you through the places missing pieces usually turn up: every bag and the box, inside what you have already built, the last few steps you followed, and look-alike colours such as White and Trans-Clear or Light Gray and Light Bluish Gray. If the piece really is gone, it lists the set piece by piece so you leave with the element ID LEGO asks for in a replacement request, or a link to buy the part.
Open the Missing Piece Checker
Sorting Planner
List the sets your pieces came from and choose how many bins or drawers you have, from four to forty. The planner sorts by part type rather than colour, so you look for a shape instead of digging through a bucket of one colour, and it sizes every bin from the real piece counts of your sets. Small families fold into an "everything else" bin when you have few bins, and large families split when you have bins to spare. You can print bin labels and download a parts spreadsheet with the plan.
Open the Sorting Planner
For building and designing
Brick Mosaic Maker
Choose a photo and the maker turns it into a brick mosaic in the colours of a LEGO Art or mosaic set, at 32, 48 or 64 studs square, in round or square tiles. Pick a set and the mosaic uses only that set's colours, never more of a colour than the set holds, or let it use every colour those sets contain and see what each needs. It counts the pieces per colour and lets you download the design as an LDraw file to build from or open in 3D. The photo stays in your browser; nothing is uploaded.
Open the Brick Mosaic Maker
LDraw Model Checker
Open an LDraw model (.ldr or .mpd, the format most LEGO building programs can export) and the checker lists every part it uses with a link to that part's page, works out which plain bricks, plates and tiles actually connect, flags anything that looks wrong, and compares two versions of a build to show what changed. It runs in your browser, so the file never leaves your device. The first start downloads about 7 MB, which your browser then keeps.
Open the LDraw Model Checker
LDraw 3D Viewer
Open the same kind of file to turn the model around in 3D, zoom in on any corner, spread the parts apart and step through the build the way instructions do. Large models, such as a whole mosaic, stay smooth to move. A mosaic from the Brick Mosaic Maker can open here directly, or from its downloaded file when it is too large to pass across. Like the checker, it runs in your browser.
Open the LDraw 3D Viewer
For choosing a set
Gift Finder
Four steps: who the gift is for, their interests, their building level and your budget. The picks come from sets in our catalog that match those answers, with each card's facts taken from the catalog; the AI only writes the words around them.
Start the Gift Finder
Set Comparison Tool
Put up to four sets side by side to compare price, piece count, dimensions, features and price per piece.
Compare sets
Price Per Piece Calculator
Enter a price and a piece count, or pick a set, to see its price per piece and how that compares with benchmarks for the theme and with the set's list price.
Open the calculator
Build Time Estimator
Pick a set or enter a piece count, choose your skill level and the set's complexity, and get an estimate of how long the build will take, with a build plan.
Estimate a build
Display Space Calculator
Enter your shelf's dimensions to check whether a set fits, in every orientation, with reference sizes for common shelving. For how to plan a whole display, see How to Display Your LEGO Collection.
Check the fit
AI Set Recommender and BlockTalk
Describe what you want in your own words, a theme, a budget, who it is for, and the AI Set Recommender suggests sets from our catalog. BlockTalk is the same assistant as a conversation, for follow-up questions about sets, themes and buying. Both count toward the ten AI answers a visitor gets every 24 hours.
For a collection
Collection Value Tracker
List the sets you own with what you paid and compare that with current values from our pricing data. The page itself says it is educational content, not financial advice, and so is anything it estimates. For what our market data shows about retired sets, read the LEGO Investment Guide.
Open the value tracker
Collection Completionist
Choose a theme and tick the sets you own to see which ones you are missing. Your ticks are saved in your browser's own storage on that device, so clearing browser data or switching devices starts the list again.
Open the Collection Completionist
Guides that work like tools
The Modular Buildings guide covers every modular building with display, lighting and collecting notes, and the LEGO sets retiring in 2026 guide lists expected exit dates from our catalog. All the tools are listed together on the tools page.
The site may earn a commission on purchases made through its links. The tools are free to use.
