MOC Parts List Guide: Plan, Generate and Buy Your Bricks

For every MOC (My Own Creation) builder, the parts list (also called a BOM) is the bridge between a design file and a model you can actually put on the shelf. Without a clear list, even a brilliant design stays trapped on screen. This guide walks through how to plan, organize and purchase the parts for your next build so the whole process runs smoothly.

Why Is a Parts List So Important?

A very common beginner mistake: you spot a design you love, immediately start digging through the parts bins, and stall halfway through because something is missing. A complete MOC parts list prevents that:

• Accurate purchasing: you know exactly what you need and how many, so you avoid double-buying or missing items
• Cost control: you can estimate the total spend up front and decide whether sourcing from scratch is worth it
• Substitutions: rare parts surface early, giving you time to find alternatives or adjust the design

Our brick plans download guide covers how to find high-quality MOC instructions on the major platforms. The first thing to do once you have the file is work through the parts list.

1. How to Classify a Parts List

A mature MOC parts list is usually organized along these lines:

By Color

This is the most intuitive approach. Grouping parts by color lets you locate pieces quickly while building. Note the color code for each part in the list (for example LEGO's BrickLink color IDs) so you avoid mismatched shades.

By Part Type

• Standard bricks: basic bricks, plates, slopes
• Special parts: tiles, printed parts, curved slopes
• Technic: pins, beams, gears, axles
• Minifig accessories: weapons, headgear, tools
• Decorated parts: stickered and printed elements (check whether a plain version can substitute)

By Rarity

Split parts into "common", "rare" and "retired". This tells you what to prioritize. Common parts can be pulled from your loose bins, rare parts need to be ordered ahead of time, and retired parts mean you should start thinking about substitutes.

2. How to Generate a Parts List

Option 1: Manual Entry (Small Builds)

For builds under 200 parts, typing the list into Excel or Google Sheets is fine. Include: index number, part name, part number, color, quantity, and notes (such as substitution options).

Option 2: Use Rebrickable

Rebrickable is the largest MOC parts database in the world. Upload your design file (.io/.ldr/.mpd) and the system generates a complete parts list automatically, flagging how well each part matches your inventory and suggesting where to buy. It is the tool professional MOC builders reach for most often.

Option 3: BrickLink Part Designer

If you design in BrickLink Studio, the built-in Part Designer exports a parts list as XML. Import it into a BrickLink Wanted List and you can order everything in a single pass.

3. Where to Buy Parts

Once the list is ready, the next step is sourcing. Here is how the main channels compare:

Channel	Strengths	Weaknesses	Best for
BrickLink	Largest marketplace, widest part selection	High international shipping, slow delivery	Rare and retired parts
Taobao / Pinduoduo	Cheap, fast domestic shipping	Inconsistent quality, sellers need vetting	Bulk orders of common parts
Xianyu (secondhand)	Chance to buy parted-out retired sets	Part condition is uncertain	Retired and special parts
Brickplan.cn	One-stop plans plus matched parts lists	Coverage still expanding	Parts for plans hosted on the platform

Tip: on brickplan.cn you will find plenty of popular MOC plans, and each one ships with a prepared parts list, which saves you the manual sorting work.

4. Advanced Parts List Management

Build a Personal Parts Inventory

If you build MOCs regularly, set up a database of what you own. Enter every set and loose part into BrickLink's My Inventory or Rebrickable's My Sets. When you open a new plan, the system then calculates which parts you already have and which you still need to buy, keeping the budget under control.

Substitution Strategies

Stuck on a rare part? Try these in order:

1. Color substitution: swap a rare color for a common one in the same part
2. Functional substitution: use different parts to do the same job (for example a standard brick plus plate in place of an odd-sized brick)
3. Structural tweaks: adjust the design slightly to avoid the point that requires the rare part

Bulk Buying Tips

• For basics like 1x1 bricks and 1x2 plates, buy in lots of 100 or more for a lower average unit price
• For wear-and-loss items such as Technic pins and gears, keep about 20% extra in reserve
• Watch for the "Lots with 10+" marker on BrickLink: the more you buy from one store, the better the shipping cost spreads out

5. From Parts List to Finished Build

When everything has arrived, prepare in this order:

1. Sort and store: use compartment boxes and divide parts by color or type
2. Check the list: count each line item and confirm before you start building
3. Pull parts step by step: take out only what the current instruction step needs, which keeps the build from turning into chaos

If you want to get better at building from digital instructions, read our digital brick plans guide for tips on using plans efficiently on a tablet or phone.

Final Thoughts

A parts list looks like tedious prep work, but good preparation is half the job. A clearly classified, fully detailed list saves hours of hunting through bins and keeps purchasing costs in check, turning a frantic build into a controlled one. Whether you are just starting out or have years of builds behind you, the habit of "list first, buy second, build third" pays off every time. Open brickplan.cn, pick a plan you like, and start your next build from the parts list.