Mietkaution: how much is allowed? (2026)
Mietkaution: how much is allowed?
At most three Nettokaltmieten, the rent excluding Nebenkosten.
You may pay it in three equal monthly instalments, the first due at the start of the tenancy (§ 551 Abs. 2 BGB). The landlord must hold the Kaution separately from their own assets and earn interest on it; the interest belongs to you (§ 551 Abs. 3 BGB).
§ 551 Abs. 1 BGBIn 60 seconds
For residential lettings the Kaution may not exceed three Nettokaltmieten: calculated on the rent excluding heating and operating costs, not on the Warmmiete (§ 551 Abs. 1 BGB).
You may pay in three equal monthly instalments. The first falls due at the start of the tenancy, the other two with the following rent payments (§ 551 Abs. 2 BGB).
An agreement for more than three Nettokaltmieten is void as to the excess. You can reclaim what you overpaid (§ 551 Abs. 1 and 4 BGB).
The landlord must hold the Kaution separately from their own assets and bearing interest. The interest belongs to you and increases the deposit (§ 551 Abs. 3 BGB).
Barkaution, Mietkautionsbürgschaft and pledging a savings account are the usual forms. The three-month ceiling applies to all of them.
What the law says
Where the tenant is to provide the landlord with security for the performance of their obligations, that security may not exceed three times the monthly rent, excluding operating costs shown as a flat rate or as an advance payment (subject to § 551 Abs. 3 sentence 4). Working translation; the German original is the binding text.
A worked example
A flat with €800 Nettokaltmiete and €200 in advance Nebenkosten. The Warmmiete is €1,000.
The figure here is 3 × €800 = €2,400, not the €1,000 Warmmiete. A deposit pegged to the Warmmiete would be too high.
What is the Mietkaution?
The Mietkaution is security you give the landlord at the start of the tenancy. It covers possible claims. Unpaid rent, owed Nebenkosten, or damage beyond normal wear and tear. As long as none of that arises, you get it back in full after you move out.
What forms of Kaution are there?
The deposit need not be cash. Three forms are common. The ceiling of three Nettokaltmieten applies to all of them:
| Form | How it works | For you |
|---|---|---|
| Barkaution / Kautionskonto | You pay money; the landlord holds it separately and with interest (§ 551 Abs. 3 BGB) | Cash is tied up but earns interest; the interest is yours |
| Mietkautionsbürgschaft | A bank or insurer guarantees the sum for a fee | No capital tied up, but an ongoing fee |
| Verpfändung of a savings account | You pledge your own savings book in the landlord's favour | The money stays in your account and earns interest |
Which form applies is for you and the landlord to agree; there is no legal right to a particular one.
For how you get the deposit back at the end, including the review period and interest, see Reclaiming your Kaution.
What it means for each side
- Check the deposit against the Nettokaltmiete before you pay.
- Pay in three instalments if you prefer: the contract cannot take that right away.
- Reclaim anything overpaid; the excess portion you need not pay at all.
- Ask where the deposit is held. You are entitled to a separate, interest-bearing account.
- Calculate the cap on the Nettokaltmiete, not on the Warmmiete.
- Do not make the handover conditional on full payment, only the first instalment is owed at the start.
- Hold a Barkaution in a separate, interest-bearing account, apart from your own assets.
- An excessive clause does not protect you; it is void as to the excess.
Common mistakes
The basis is three Nettokaltmieten alone, not the rent including Nebenkosten.
Your right to instalments under § 551 Abs. 2 BGB is always available to you.
You do not have to pay more than three Nettokaltmieten. The excess is void.
You are entitled to a separate, interest-bearing account and may demand proof.
What to do next
Find the Nettokaltmiete in your tenancy agreement and multiply it by three, that is the ceiling.
If the agreed Kaution is higher, reclaim the excess in writing (§ 551 Abs. 1 and 4 BGB).
At move-in, document the condition of the flat in full. What can later be deducted from the deposit depends on it. Do it with BildProof, about two minutes a room →
Frequently asked questions
How much Kaution is allowed?
For residential lets, at most three Nettokaltmieten (net cold rents), that is, rent without heating and operating costs (§ 551 Abs. 1 BGB). If your Nettokaltmiete is 800 euros, the maximum Kaution is 2,400 euros. This limit is mandatory and cannot be raised against you in the lease.
Can I pay the Kaution in instalments?
Yes. Under § 551 Abs. 2 BGB you may pay the Kaution in three equal monthly instalments. The first is due at the start of the tenancy, the other two with the following two rent payments. The landlord cannot exclude this right in the lease. A clause demanding the full deposit upfront is void to that extent.
Do I get interest on my Kaution?
Yes. The landlord must hold the Kaution separately from their own assets and earn interest on it, customarily at the rate for savings deposits with three months' notice (§ 551 Abs. 3 BGB). The interest belongs to you and increases the Kaution. If the landlord fails to invest it properly, you can still claim the interest that would have accrued.
What if the landlord demands more than three Nettokaltmieten?
An agreement for more than three Nettokaltmieten is void for the excess (§ 551 Abs. 1 and 4 BGB). The permissible part stays valid and you can reclaim any overpayment. You never owe more than three Nettokaltmieten, regardless of what the lease says.
What is the difference between Barkaution, Bürgschaft and Verpfändung?
With a Barkaution (cash deposit, held on a Kautionskonto) you pay money that the landlord holds separately and with interest. With a Mietkautionsbürgschaft (deposit guarantee) a bank or insurer guarantees the sum for a fee, so you tie up no cash. With a Verpfändung (pledge) you pledge your own savings account. The form is agreed with the landlord. The cap of three Nettokaltmieten always applies.
This page gives general information as at the date shown. It does not replace legal advice on an individual case.