If your extension does not go through in the SIXT app or under Manage Booking, it is usually caused by one of the following reasons. Message us on WhatsApp or Live Chat and we'll review your booking and find a solution together.
Common reasons
Payment method: insufficient balance or credit limit for re-authorization
Maximum rental period reached: the vehicle needs to be swapped for another
Extension beyond 28 days: a direct extension is not possible — a new booking is required
Quick fixes
Check your payment method and available credit limit
Try requesting a shorter extension period
Make a new booking and swap to another vehicle at a SIXT branch if the maximum rental period has been reached
Still need help? Find our contact options below — please have your rental agreement number ready.
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How to extend
Open the SIXT app or sign in on the SIXT website under Manage Booking
Select your current rental
Adjust the return date and confirm
The extension takes effect immediately, provided the authorization is successful
Longer than 28 days?
A direct extension is not possible beyond 28 days — simply make a new booking, ideally in advance so the transition is seamless.
Extension not working?
Two common reasons:
Payment method: check whether you have sufficient available balance or credit limit
Maximum rental period reached: the vehicle is being returned to the fleet — make a new booking and swap to another vehicle at a SIXT branch
When is an additional day charged? All rentals are calculated on a 24-hour billing cycle:
Example 1: Pick up at 12:00 on day one and return at 12:00 on day two ? 1 day charged
Example 2: Return at 13:00 on day two ? an additional day is charged
This keeps your billing transparent and easy to follow.
Next step
Extend your rental on the SIXT website or in the SIXT app.
Still need help? Find our contact options below — please have your rental agreement number ready.
","actions":[{"key":"FAQ.bookingList","displayValue":"Manage booking"}]},{"text":"Why was my SIXT online extension rejected?","href":"/help-center/articles/why-was-my-sixt-online-extension-rejected/","content":"If your extension does not go through in the SIXT app or under Manage Booking, it is usually caused by one of the following reasons. Message us on WhatsApp or Live Chat and we'll review your booking and find a solution together.
Common reasons
Payment method: insufficient balance or credit limit for re-authorization
Maximum rental period reached: the vehicle needs to be swapped for another
Extension beyond 28 days: a direct extension is not possible — a new booking is required
Quick fixes
Check your payment method and available credit limit
Try requesting a shorter extension period
Make a new booking and swap to another vehicle at a SIXT branch if the maximum rental period has been reached
Still need help? Find our contact options below — please have your rental agreement number ready.
","actions":[{"key":"FAQ.bookingList","displayValue":"Manage booking"}]},{"text":"How much does it cost to extend my SIXT rental?","href":"/help-center/articles/how-much-does-it-cost-to-extend-my-sixt-rental/","content":"An extension is calculated at the daily rate of your original booking. Any booked extras (additional driver, protection package, GPS, child seat) are added at their respective daily rates. You will see the exact amount before you confirm.
How it is billed
The extension is shown as a separate line item on your final invoice at return.
Next step
Check your extension price on the SIXT website or in the SIXT app.
Still need help? Find our contact options below — please have your rental agreement number ready.
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