How To Create Sub Decks In Anki: The Complete Step-by-Step Hierarchical Deck Guide

Organizing your flashcard database is vital for long-term retention and structured learning. By learning how to create sub decks in Anki, you can segment massive subjects into highly granular, manageable review hierarchies using drag-and-drop actions or the double-colon naming syntax. This structural optimization streamlines study sessions, enables precise control over daily card limits, and prevents cognitive overload during spaced repetition cycles.

Pre-Optimization Planning and Deck Architecture Strategy

Before creating a complex system of sub decks, you must plan your card architecture. Anki uses a database structure where cards reside within decks, but they can also be filtered, searched, and sorted using tags. Beginners often make the mistake of creating dozens of micro-decks for narrow topics, which can degrade database performance and break the natural randomness of spaced repetition.

Sub decks are ideal when you require different study parameters for specific topics. For example, if you are studying medicine, you may want a parent deck called Pharmacology with separate daily review limits and card-retrieval schedules for sub decks like Antibiotics and Cardiovascular Drugs. However, if you only want to organize cards for searching or occasional custom study sessions, tagging is the superior design pattern.

Pre-Requisite Setup Checklist

• Software Version Compatibility: Ensure you are running Anki Desktop version 2.1.49 or newer. The V3 scheduler, enabled by default in newer versions, handles sub deck limits much more intuitively than legacy engines.
• Essential Equipment: Anki Desktop (Windows, macOS, or Linux) is highly recommended for structure changes, as bulk renaming and dragging are far more reliable on desktop than on AnkiMobile or AnkiDroid.
• Prerequisite Knowledge: Basic familiarity with the Anki home screen dashboard, deck creation, and the deck options preset menu.
• Database Backup: Before performing major structural reorganizations, go to File, select Export, and save a backup of your collection including media files to prevent data loss.
• Estimated Setup Duration: 5 to 10 minutes for configuration and initial nesting.

Execution Guide: Three Methods for Creating Sub Decks in Anki

Anki offers multiple ways to build hierarchical structures. Below are the three most efficient methods to create, manage, and scale your sub decks.

Step 1: Navigating the Deck Dashboard and Initializing Parent Decks

To build a nested hierarchy, you must first establish the top-level parent decks that will house your sub decks.

1. Open Anki Desktop and ensure you are on the Decks screen.
2. Click the Create Deck button located at the bottom of the main interface window.
3. In the pop-up dialog box, type the name of your primary category, such as Medical School, and click OK.
4. Repeat this step to create secondary categories that you eventually want to turn into sub decks, such as Anatomy and Physiology. At this point, all decks will exist as flat, independent items on your main dashboard list.

Warning: Avoid creating more than three levels of depth (Parent::Child::Grandchild) as deeply nested sub decks can cause display bugs on smaller mobile screens and complicate search queries in the Anki Browser.

Step 2: Nesting Decks via the Drag-and-Drop Interface

The fastest and most visual method to create a sub deck is the drag-and-drop mechanism on the desktop client.

1. Locate the deck on your list that you want to transform into a sub deck (e.g., Anatomy).
2. Click and hold the left mouse button over this deck's name.
3. Drag the deck directly on top of the intended parent deck name (e.g., Medical School). The parent deck name should highlight or show a visual boundary box.
4. Release the mouse button. The dashboard will instantly update, showing the sub deck indented beneath the parent deck.
5. Click the small plus or minus sign (or folder toggle icon) to the left of the parent deck to collapse or expand your newly created hierarchy.

Pro-Tip: If you drag a deck and it does not nest, check if you have sorted your dashboard alphabetically or search-filtered your view. The drag-and-drop feature requires the default dashboard view to function correctly.

Step 3: Utilizing the Double-Colon Naming Convention

For advanced users, bulk deck creation, or those working on mobile devices, the double-colon syntax is the most precise way to establish hierarchical relationships. Anki reads the double colon (::) as a structural separator.

1. Click Create Deck at the bottom of the home screen, or click the gear icon next to an existing deck and select Rename.
2. To create a sub deck from scratch, type the exact name of the parent deck, followed by two colons, and then the name of the child deck. For example, type Language Learning::Spanish::Vocabulary.
3. Click OK. Anki will automatically generate the parent deck Language Learning, the sub deck Spanish, and the nested grandchild deck Vocabulary all at once.
4. If the parent deck already exists, typing Language Learning::French::Verbs will instantly place the new French and Verbs decks underneath the pre-existing parent structure without duplicating it.

Step 4: Configuring Preset Options and Limit Inheritance

A critical part of sub deck management is understanding how settings like daily card limits and ease intervals cascade through your hierarchy.

1. Locate your top-level parent deck, click the gear icon to its right, and select Options.
2. Under the Preset dropdown at the top of the options window, you can apply a specific preset to this deck.
3. In the V3 scheduler, sub decks inherit options from their parent decks unless you explicitly assign a different options preset to the sub deck itself.
4. If your parent deck has a New Cards/Day limit of 20, and you have three sub decks, the total number of new cards you will see across all three sub decks combined will cap at 20 when you click and study the parent deck.
5. If you want to study each sub deck with its own independent limits, click the gear icon next to each sub deck, choose Options, and select or create a separate preset for each.

Anki Deck Architecture: Sub Decks vs. Tags Parameters

The table below breaks down the technical differences, performance characteristics, and ideal use cases for sub decks compared to tags.

Resolving Hierarchy Failures and Syncing Complications

When editing and structuring sub decks, database mismatches or configuration errors can disrupt your workflow. Below are common real-world failures and their solutions.

Scenario 1: Sub Decks Not Displaying Cards During Review

You click on a parent deck to study, but Anki says you are finished, even though your nested sub decks clearly show that new cards and reviews are waiting.

• Root Cause: The daily limits set on your parent deck are lower than the limits on your sub decks, or you have reached the parent limit for the day. Under the default configuration, if the parent deck limit is set to 10 new cards per day, you will only see 10 new cards total from across all child decks, even if each child deck has a individual limit of 20.
• Actionable Fix: Click the gear icon next to the parent deck and choose Options. Under the limits section, increase the daily review and new card limits of the parent deck to a number equal to or greater than the combined sum of all your sub deck limits.

Scenario 2: Broken Hierarchy or "Orphaned" Decks on Mobile Devices

After syncing your desktop collection to AnkiWeb and opening AnkiDroid or AnkiMobile, your sub decks appear as flat, independent decks with long names like Parent::Child rather than indented, nested items.

• Root Cause: A mismatch between the desktop scheduler version and the mobile application settings, or a syntax error such as using single colons or adding spaces around the double colons.
• Actionable Fix: Edit the deck name and remove any spaces around the double colons (e.g., change Parent :: Child to Parent::Child). Additionally, check your mobile app settings and ensure that your database is fully synced and that the V3 scheduler is enabled in your preferences.

Scenario 3: Database Slowdowns or Failure to Sync Media Files

Your Anki client takes several minutes to sync, or displays a warning message advising you that your collection database has too many individual nodes.

• Root Cause: You have created too many individual sub decks (often over 200). Each deck in Anki is treated as a separate database entity, which puts significant strain on the sync engine during schema updates.
• Actionable Fix: Consolidate your micro-decks. Move cards into broader parent decks and use tags for fine-grained classification. You can convert sub decks to tags by selecting all cards within a sub deck in the Browser, choosing Add Tags, naming the tag, and then deleting the empty sub deck.

Frequently Asked Questions

How many levels of sub decks can you create in Anki?

Anki technically allows you to nest sub decks indefinitely using the double-colon syntax. However, practical interface limitations on desktop and mobile platforms make more than three levels of depth highly counterproductive, as names will be truncated and navigation becomes tedious.

Do sub decks inherit study settings and presets from the parent deck?

By default, sub decks inherit whatever card options and limits are assigned to their parent deck if they are set to use the same preset. If you want a sub deck to have independent limits, you must open its individual options menu and assign a unique options preset.

Why does my card count change when I collapse or expand my parent deck?

When a parent deck is collapsed, the dashboard displays the cumulative total of all new, learning, and review cards across both the parent deck and all of its nested child decks. Expanding the parent deck isolates the counts, showing you exactly how many cards reside in each specific sub-category.

How do I safely delete a parent deck without losing the cards in my sub decks?

If you delete a parent deck, Anki will also delete all of its nested child decks and all the cards within them. To preserve your sub decks, drag them out of the parent hierarchy on the dashboard (or rename them to remove the parent prefix) before deleting the empty parent deck container.

Master Your Spaced Repetition Workflow

Now that your decks are organized, you can focus on building high-quality cards and maintaining your daily reviews. To take your studying to the next level, experiment with filtered decks to temporarily pull cards from various sub decks for targeted exam preparation.