A student rent deposit (Mietkaution) is usually the first large payment before moving into a flat in Germany. The rules on how high it may be, whether you can pay in instalments and what happens to the money are set out in the German Civil Code (BGB). This guide explains the rules for a cash deposit on residential tenancies, works through an example and shows what to check before you sign. For the wider topic, see the German overview Wohnen im Studium (in German).
Short answer: A cash deposit may not exceed three times the monthly rent (§ 551 para. 1 BGB, as of November 2026). You can pay it in three equal monthly instalments, the first at the start of the tenancy. The landlord must keep the money separate from their own assets. The interest belongs to you and increases the security.
The most important points at a glance
- A cash deposit may not exceed three times the monthly rent (§ 551 para. 1 BGB).
- Advance payments for service charges (Betriebskostenvorauszahlungen) are not counted in this calculation.
- You may pay the deposit in three equal monthly instalments (§ 551 para. 2 BGB).
- The landlord must keep the money separate from their own assets, and the interest belongs to you (§ 551 para. 3 BGB).
- In a student or youth residence there is no obligation to pay interest.
How high may the rent deposit be?
The upper limit is three times the monthly rent. The calculation uses the rent without advance payments for service charges, which are shown as a flat amount or as advance payments (§ 551 para. 1 BGB). The table below shows the maximum for some sample rents. The figures are assumptions for calculation, not market values.
| Monthly rent without service charges (assumption) | Maximum deposit | One instalment in three payments |
|---|---|---|
| 350 euros | 1,050 euros | 350 euros |
| 450 euros | 1,350 euros | 450 euros |
| 550 euros | 1,650 euros | 550 euros |
| 650 euros | 1,950 euros | 650 euros |
Can I pay the deposit in instalments?
Yes, if you provide it in money. Under § 551 para. 2 BGB you may pay the security in three equal monthly instalments. The first instalment is due at the start of the tenancy, and the further instalments fall due together with the rent payments that follow directly. This matters most if you cannot raise the whole sum on the day you move in.
Assumption: the maximum is 1,050 euros. Each of the three instalments is then 350 euros. You pay the first instalment when you move in, and the second and third with the rent payments that follow.
- Calculate the maximum: three months of rent without service charge advances.
- Divide the amount by three to get the size of each instalment.
- Check in the tenancy agreement when the first and the further instalments are due.
- Keep track of the payments on your bank statement and keep the proof.
Where does the deposit go? Investment and interest
The landlord must invest the security with a credit institution at the usual interest rate for savings deposits with a three-month notice period. The parties may also agree on another form of investment. In both cases the investment must be kept separate from the landlord’s assets (§ 551 para. 3 BGB).
The income from the investment belongs to you as the tenant and increases the security. In a student or youth residence, by contrast, there is no obligation to pay interest. Ask for written confirmation at move-in of how and where the sum is invested.
What are the alternatives?
Instead of a cash deposit you can use a deposit insurance policy. The guide Kautionsversicherung statt Mietkaution explains the differences between the two routes (in German). This article sticks to the classic cash deposit, to which the rules above apply directly.
What to clarify before you sign
| Point | What to check |
|---|---|
| Amount | No more than three months of rent without service charge advances |
| Payment | Whether three instalments are agreed and when they fall due |
| Investment | Credit institution or other agreed form, separate from the landlord’s assets |
| Proof | Written confirmation of amount, account and investment |
| Interest | The income from the investment belongs to you |
Frequently asked questions
May the landlord ask for more than three months of rent?
No. Under § 551 para. 1 BGB the security may not exceed three times the monthly rent. Agreements that deviate to the tenant’s disadvantage are void (§ 551 para. 4 BGB). Read the contract carefully before you sign.
Do I have to pay the deposit in one sum?
No, if you provide it in money. You are then entitled to make three equal monthly instalments (§ 551 para. 2 BGB). The first instalment is due at the start of the tenancy.
Do I get interest on my deposit?
Yes. The income belongs to you and increases the security (§ 551 para. 3 BGB). In a student or youth residence, however, there is no obligation to pay interest. The rate depends on the credit institution.
How do I secure my claim to the deposit?
Keep the contract and payment receipts, and ask for written confirmation if the money goes into a deposit account. You will need these documents when the deposit is returned. The guide on getting your deposit back after moving out explains that process (in German).
What if the landlord does not keep the deposit separate?
Section 551 para. 3 BGB requires the investment to be separate from the landlord’s assets. Raise a missing separation in writing with the landlord and ask for proof of the account and the amount. If the position stays unclear, a tenants’ association or legal advice can help.
What to do now
- Treat three times your monthly rent without service charge advances as the upper limit.
- Ask for the payment method and the due dates of the instalments in writing.
- Ask how and where the deposit is invested, and keep the proof.
- Record move-in and payments so that you can document everything when you move out.
Common mistakes with the deposit
Many problems come not from the amount but from missing paperwork. If you pay the deposit without written confirmation, you will later find it hard to prove how much you paid and when. That matters when the deposit is returned after you move out.
Instalment due dates are just as often overlooked. If you forget the second or third instalment, you fall into arrears on a claim under the tenancy. Put the due dates in your calendar as soon as the contract is signed.
- Accepting the amount without checking the upper limit yourself.
- Skimming the tenancy agreement and skipping the deposit clause.
- Not keeping payment receipts, even if a flatmate transfers the money for you.
- Not asking after move-in how and where the deposit is held.
Deposits in a shared flat
In a flat share with a joint tenancy agreement, the deposit is often paid once for everyone. Agree internally who pays which share and who keeps the proof. This avoids disputes when someone moves out early or the deposit is returned.
If the deposit only covers a single room, you also need to decide how the sum is split among the residents. Settle this in advance and record it in writing. For questions about notice and moving out, see Kündigungsfrist im WG-Zimmer (in German).
Related guides
- Student Housing in Germany: Rent, Shared Flats, Halls and Housing Benefit
- Kautionsversicherung statt Mietkaution
- Checking a German Service Charge Statement: Deadlines and Errors
- Flat Hunting as a Student in Germany: Your Rights and Duties
Sources: § 551 BGB, limitation and investment of security (German) (as of November 2026).
Last updated: November 2026. This guide is general information, not individual advice.
