diff --git a/src/y-indexeddb.js b/src/y-indexeddb.js
index 07f4fbb..ca06a47 100644
--- a/src/y-indexeddb.js
+++ b/src/y-indexeddb.js
@@ -6,7 +6,7 @@ import { Observable } from 'lib0/observable'
 const customStoreName = 'custom'
 const updatesStoreName = 'updates'
 
-export const PREFERRED_TRIM_SIZE = 500
+export const DEFAULT_PREFERRED_TRIM_SIZE = 500
 
 /**
  * @param {IndexeddbPersistence} idbPersistence
@@ -36,7 +36,7 @@ export const fetchUpdates = (idbPersistence, beforeApplyUpdatesCallback = () =>
 export const storeState = (idbPersistence, forceStore = true) =>
   fetchUpdates(idbPersistence)
     .then(updatesStore => {
-      if (forceStore || idbPersistence._dbsize >= PREFERRED_TRIM_SIZE) {
+      if (forceStore || idbPersistence._dbsize >= idbPersistence._trim) {
         idb.addAutoKey(updatesStore, Y.encodeStateAsUpdate(idbPersistence.doc))
           .then(() => idb.del(updatesStore, idb.createIDBKeyRangeUpperBound(idbPersistence._dbref, true)))
           .then(() => idb.count(updatesStore).then(cnt => { idbPersistence._dbsize = cnt }))
@@ -55,14 +55,21 @@ export class IndexeddbPersistence extends Observable {
   /**
    * @param {string} name
    * @param {Y.Doc} doc
+   * @param {Object} [options={}]
+   * @param {number} [options.preferredTrimSize=500]
    */
-  constructor (name, doc) {
+  constructor (name, doc, options = {}) {
     super()
     this.doc = doc
     this.name = name
     this._dbref = 0
     this._dbsize = 0
     this._destroyed = false
+    /**
+     * The preferred size of updates after which IndexedDB data is trimmed.
+     * @type {number|number}
+     */
+    this._trim = options.preferredTrimSize || DEFAULT_PREFERRED_TRIM_SIZE
     /**
      * @type {IDBDatabase|null}
      */
@@ -108,7 +115,7 @@ export class IndexeddbPersistence extends Observable {
       if (this.db && origin !== this) {
         const [updatesStore] = idb.transact(/** @type {IDBDatabase} */ (this.db), [updatesStoreName])
         idb.addAutoKey(updatesStore, update)
-        if (++this._dbsize >= PREFERRED_TRIM_SIZE) {
+        if (++this._dbsize >= this._trim) {
           // debounce store call
           if (this._storeTimeoutId !== null) {
             clearTimeout(this._storeTimeoutId)
diff --git a/tests/y-indexeddb.tests.js b/tests/y-indexeddb.tests.js
index fcc7456..fa09913 100644
--- a/tests/y-indexeddb.tests.js
+++ b/tests/y-indexeddb.tests.js
@@ -1,6 +1,6 @@
 
 import * as Y from 'yjs'
-import { IndexeddbPersistence, clearDocument, PREFERRED_TRIM_SIZE, fetchUpdates } from '../src/y-indexeddb.js'
+import { IndexeddbPersistence, clearDocument, DEFAULT_PREFERRED_TRIM_SIZE, fetchUpdates } from '../src/y-indexeddb.js'
 import * as t from 'lib0/testing.js'
 import * as promise from 'lib0/promise.js'
 
@@ -42,12 +42,12 @@ export const testIdbUpdateAndMerge = async tc => {
   await persistence2.whenSynced
   t.assert(calledObserver)
   t.assert(arr2.length === 2)
-  for (let i = 2; i < PREFERRED_TRIM_SIZE + 1; i++) {
+  for (let i = 2; i < DEFAULT_PREFERRED_TRIM_SIZE + 1; i++) {
     arr1.insert(i, [i])
   }
   await promise.wait(100)
   await fetchUpdates(persistence2)
-  t.assert(arr2.length === PREFERRED_TRIM_SIZE + 1)
+  t.assert(arr2.length === DEFAULT_PREFERRED_TRIM_SIZE + 1)
   t.assert(persistence1._dbsize === 1) // wait for dbsize === 0. db should be concatenated
 }
 
@@ -70,11 +70,11 @@ export const testIdbConcurrentMerge = async tc => {
   await persistence2.whenSynced
   t.assert(arr2.length === 2)
   arr1.insert(0, ['left'])
-  for (let i = 0; i < PREFERRED_TRIM_SIZE + 1; i++) {
+  for (let i = 0; i < DEFAULT_PREFERRED_TRIM_SIZE + 1; i++) {
     arr1.insert(i, [i])
   }
   arr2.insert(0, ['right'])
-  for (let i = 0; i < PREFERRED_TRIM_SIZE + 1; i++) {
+  for (let i = 0; i < DEFAULT_PREFERRED_TRIM_SIZE + 1; i++) {
     arr2.insert(i, [i])
   }
   await promise.wait(100)