diff --git a/packages/nest/README.md b/packages/nest/README.md
index b957586..5caeb4c 100644
--- a/packages/nest/README.md
+++ b/packages/nest/README.md
@@ -38,25 +38,18 @@ const blockstore = new IDBBlockstore('path/to/store')
 await blockstore.open()
 
 const fs = await FileSystem.create({
-  blockstore
+  blockstore,
 })
 
 // Create the private node of which we'll keep the encryption key around.
 const { capsuleKey } = await fs.mountPrivateNode({
-  path: Path.root() // ie. root private directory
+  path: Path.root(), // ie. root private directory
 })
 
 // Write & Read
-await fs.write(
-  Path.file('private', 'file'),
-  'utf8',
-  '🪺'
-)
-
-const contents = await fs.read(
-  Path.file('private', 'file'),
-  'utf8'
-)
+await fs.write(Path.file('private', 'file'), 'utf8', '🪺')
+
+const contents = await fs.read(Path.file('private', 'file'), 'utf8')
 ```
 
 Scenario 2:<br />
@@ -73,11 +66,7 @@ of our root tree, the pointer to our file system.
 let fsPointer: CID = await fs.calculateDataRoot()
 
 // When we make a modification to the file system a verification is performed.
-await fs.write(
-  Path.file('private', 'file'),
-  'utf8',
-  '🪺'
-)
+await fs.write(Path.file('private', 'file'), 'utf8', '🪺')
 
 // If the commit is approved, the changes are reflected in the file system and
 // the `commit` and `publish` events are emitted.
@@ -103,7 +92,7 @@ const fs = await FileSystem.fromCID(fsPointer, { blockstore })
 // `capsuleKey` from scenario 1
 await fs.mountPrivateNode({
   path: Path.root(),
-  capsuleKey
+  capsuleKey,
 })
 ```
 
@@ -115,6 +104,7 @@ await fs.mountPrivateNode({
 fs.exists
 fs.listDirectory // alias: fs.ls
 fs.read
+fs.size
 ```
 
 ### Mutations
@@ -153,12 +143,16 @@ import { Modification } from '@wnfs-wg/nest'
 
 const fs = FileSystem.create({
   blockstore,
-  onCommit: (modifications: Modification[]): { commit: boolean } => {
+  onCommit: async (
+    modifications: Modification[]
+  ): Promise<{ commit: boolean }> => {
     // For example, check if I have access to all paths.
-    const satisfied = modifications.every(m => ALLOWED_PATHS.includes( Path.toPosix(m.path) ))
+    const satisfied = modifications.every((m) =>
+      ALLOWED_PATHS.includes(Path.toPosix(m.path))
+    )
     if (satisfied) return { commit: true }
     else return { commit: false }
-  }
+  },
 })
 ```
 
diff --git a/packages/nest/src/class.ts b/packages/nest/src/class.ts
index dba3cf9..dc75d3a 100644
--- a/packages/nest/src/class.ts
+++ b/packages/nest/src/class.ts
@@ -426,6 +426,11 @@ export class FileSystem {
     )
   }
 
+  /** @group Querying */
+  async size(path: Path.File<PartitionedNonEmpty<Partition>>): Promise<number> {
+    return await this.#transactionContext().size(path)
+  }
+
   // MUTATIONS
   // ---------
 
diff --git a/packages/nest/src/queries.ts b/packages/nest/src/queries.ts
index 2d4607c..4d1b069 100644
--- a/packages/nest/src/queries.ts
+++ b/packages/nest/src/queries.ts
@@ -136,6 +136,24 @@ export const publicReadFromCID = (
   }
 }
 
+export const publicSize = () => {
+  return async (params: PublicParams): Promise<number> => {
+    const wnfsBlockStore = Store.wnfs(params.blockstore)
+
+    const node: PublicNode | null | undefined = await params.rootTree
+      .publicRoot()
+      .getNode(params.pathSegments, wnfsBlockStore)
+
+    if (node === null || node === undefined) {
+      throw new Error('Failed to find public node')
+    } else if (node.isDir()) {
+      throw new Error('Expected node to be a file')
+    }
+
+    return await node.asFile().getSize(wnfsBlockStore)
+  }
+}
+
 // PRIVATE
 
 export type PrivateParams = {
@@ -321,3 +339,38 @@ export const privateReadFromAccessKey = (
     }
   }
 }
+
+export const privateSize = () => {
+  return async (params: PrivateParams): Promise<number> => {
+    let node
+
+    if (params.node.isDir()) {
+      if (params.remainder.length === 0) {
+        throw new Error('Expected node to be a file')
+      }
+
+      const tmpNode: PrivateNode | null | undefined = await params.node
+        .asDir()
+        .getNode(
+          params.remainder,
+          searchLatest(),
+          params.rootTree.privateForest(),
+          Store.wnfs(params.blockstore)
+        )
+
+      if (tmpNode === null || tmpNode === undefined) {
+        throw new Error('Failed to find private node')
+      } else if (tmpNode.isDir()) {
+        throw new Error('Expected node to be a file')
+      }
+
+      node = tmpNode
+    } else {
+      node = params.node
+    }
+
+    return await node
+      .asFile()
+      .getSize(params.rootTree.privateForest(), Store.wnfs(params.blockstore))
+  }
+}
diff --git a/packages/nest/src/transaction.ts b/packages/nest/src/transaction.ts
index acc1b35..7da8466 100644
--- a/packages/nest/src/transaction.ts
+++ b/packages/nest/src/transaction.ts
@@ -307,6 +307,14 @@ export class TransactionContext {
     return dataFromBytes(dataType, bytes)
   }
 
+  /** @group Querying */
+  async size(path: Path.File<PartitionedNonEmpty<Partition>>): Promise<number> {
+    return await this.#query(path, {
+      public: Queries.publicSize(),
+      private: Queries.privateSize(),
+    })
+  }
+
   // MUTATIONS
 
   /** @group Mutating */
diff --git a/packages/nest/test/class.test.ts b/packages/nest/test/class.test.ts
index 449fa12..512d149 100644
--- a/packages/nest/test/class.test.ts
+++ b/packages/nest/test/class.test.ts
@@ -557,6 +557,27 @@ describe('File System Class', () => {
     )
   })
 
+  // SIZE
+  // ----
+
+  it('returns the size of public files', async () => {
+    const path = Path.file('public', 'file')
+
+    await fs.write(path, 'bytes', new Uint8Array([1, 2, 3]))
+    const size = await fs.size(path)
+
+    assert.equal(size, 3)
+  })
+
+  it('returns the size of private files', async () => {
+    const path = Path.file('private', 'file')
+
+    await fs.write(path, 'bytes', new Uint8Array([1, 2, 3, 4]))
+    const size = await fs.size(path)
+
+    assert.equal(size, 4)
+  })
+
   // REMOVE
   // ------