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06 Numbers and Powers

Restore Line Chat History: Full Guide

Card No. 06·5963 · Updated · Standard formula, shown below

Estimated restore time 80 min
Backup size (MB)
100 MB
You entered
Internet speed (Mbps)
10 Mbps
You entered
You enter
Backup size (MB), Internet speed (Mbps)
You get
Estimated restore time
Rounding
0 dp

To restore your Line chat history, you need a backup made beforehand—Line does not keep your chats on its servers. This guide explains the restore process for iPhone and Android, including what you can recover, what you cannot, and how to avoid common pitfalls.

Formula

The calculator estimates the time to download and restore a Line chat backup based on its size and your internet speed. The formula is:

Estimated time (minutes) = (Backup size in MB × 8) / (Internet speed in Mbps)

Variables:

  • Backup size (MB) – the size of your Line backup file, usually shown in the backup settings or in your cloud storage.
  • Internet speed (Mbps) – your current download speed, which you can check with a speed test.

The factor 8 converts megabytes to megabits (1 MB = 8 Mb). The result is in minutes, assuming a stable connection. In reality, restore time also depends on server load and device performance.

Worked Example

Using the default values: Backup size = 100 MB, Internet speed = 10 Mbps.

  • Convert MB to Mb: 100 MB × 8 = 800 Mb
  • Divide by speed: 800 Mb / 10 Mbps = 80 seconds
  • Convert to minutes: 80 / 60 = 1.33 minutes

The calculator shows 1.33 minutes (rounded to 2 decimals). For a 100 MB backup at 10 Mbps, you can expect about 1 minute and 20 seconds of download time, plus processing time.

How Line Chat Backup Works

Line offers two backup methods: backup to Google Drive (Android) or iCloud (iPhone), and a manual backup that creates a local file. The cloud backup is automatic if you enable it, but it only includes text messages, images, and stickers—not videos or voice messages. Those are excluded to keep the backup small.

When you reinstall Line or switch phones, you can restore from the cloud backup during the initial setup. If you have a manual backup file (often named LINE_backup_YYYYMMDD.chat), you can restore it from the chat settings. The manual backup includes everything the cloud backup does, but you have to transfer the file yourself.

Important: Line does not store your chat history on its servers. If you uninstall the app without a backup, your chats are gone permanently. The only exception is if you have a Letter Sealing or a Linked Devices feature, but those do not back up chat content.

How to Restore from iCloud (iPhone)

If you previously backed up to iCloud, follow these steps:

  1. Reinstall Line from the App Store.
  2. Open Line and tap Start.
  3. Enter your phone number and verify it.
  4. When prompted, tap Restore Chat History.
  5. Sign in to your iCloud account if asked.
  6. Wait for the restore to finish. Do not close the app.

If the restore prompt does not appear, go to Settings > Chats > Backup and Restore and tap Restore. You need the same Apple ID that made the backup.

How to Restore from Google Drive (Android)

For Android users with a Google Drive backup:

  1. Install Line from the Google Play Store.
  2. Open Line and tap Start.
  3. Verify your phone number.
  4. Tap Restore Chat History when it appears.
  5. Choose the Google account that holds the backup.
  6. Select the backup you want (usually the latest) and confirm.

If you missed the prompt, go to Settings > Chats > Backup and Restore and tap Restore. The backup must be from the same Google account and the same phone number.

How to Restore from a Manual Backup File

Manual backups are useful when you switch between platforms (e.g., iPhone to Android) because cloud backups are tied to the OS. To restore from a manual file:

  1. Transfer the .chat file to your new device (via email, USB, or cloud storage).
  2. Install Line and log in.
  3. Go to Settings > Chats > Backup and Restore.
  4. Tap Restore and select the file.

Note: Manual backups are only valid for 14 days from creation. After that, Line deletes them from their temporary storage, so you cannot restore an old manual backup.

Common Problems and Solutions

Restore fails happen for several reasons. Here are the most common:

  • Backup not found – Ensure you are using the same phone number and OS (iOS or Android) as the original backup. If you switched platforms, only a manual backup works.
  • iCloud/Google Drive storage full – Clear space or buy more storage, then try again.
  • Outdated app version – Update Line to the latest version before restoring.
  • Network issues – Use a stable Wi-Fi connection. Restoring over mobile data may fail or be slow.
  • Backup too old – Cloud backups are kept for as long as you have the account, but manual backups expire after 14 days.

If restore fails repeatedly, delete the app and reinstall, then try again. Do not log in with a different phone number, as that will create a new account.

What You Can and Cannot Restore

Line backups include:

  • Text messages (all chats)
  • Images (up to a certain resolution)
  • Stickers
  • Voice messages (only in manual backups, not cloud)

They do not include:

  • Videos
  • Files (PDFs, documents)
  • Voice messages in cloud backups
  • Call history

Also, restoring a backup does not merge with existing chats; it replaces them. If you have current chats on the device, they will be overwritten. To keep them, export a manual backup first.

Frequently Asked Questions

Can I restore Line chats without a backup?

No. Line does not store your chat history on their servers. If you did not make a backup (cloud or manual) before uninstalling or losing your phone, there is no way to recover the chats. Always enable automatic backup in settings.

Will restoring a backup delete my current chats?

Yes. Restoring replaces your current chat history with the backup. If you have chats you want to keep, create a manual backup of the current state before restoring an older backup.

Can I restore a Line backup from iPhone to Android?

No. iCloud backups are encrypted and tied to iOS. You cannot restore them on Android. The only way to transfer chats across platforms is to use a manual backup file, which you must create and transfer within 14 days.

Why is my restore stuck at a percentage?

This usually happens due to a weak internet connection or server overload. Wait a few minutes, then check your connection. If it stays stuck, cancel and restart the restore. Do not close the app abruptly, as it may corrupt the restore.

How long does a restore take?

It depends on the backup size and your internet speed. A 100 MB backup on a 10 Mbps connection takes about 1.5 minutes to download, plus processing time. Larger backups or slower speeds take longer. Use the calculator above to estimate.

Does Line backup include photos and videos?

Photos are included, but videos are not. Images are compressed to save space. If you need original quality, save them separately. Voice messages are only included in manual backups, not cloud backups.

Related

Formula used
in t | Backup size (MB) | MB | 100 | 0
in s | Internet speed (Mbps) | Mbps | 10 | 0.1
out time | Estimated restore time | min | t * 8 / s | 0

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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