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B2B Late-payment Interest Calculator
Calculate interest on unpaid commercial invoices using the Spanish statutory rate for each half of 2026.
Partial payments
Accrued interest€291.19
Plus €40.00 fixed compensation for recovery costs.
- Outstanding principal
- €5,000.00
- Estimated total claim
- €5,331.19
| Period | Days · rate | Interest |
|---|---|---|
| 1 Feb 2026 → 1 Jul 2026 | 150 · 10.15% | €208.56 |
| 1 Jul 2026 → 28 Aug 2026 | 58 · 10.4% | €82.63 |
Indicative estimate. Check the assumptions, exclusions and official sources before making a decision.
This is an indicative estimate based on the information entered. Review the assumptions before making a tax or financial decision.
Methodology and sources Reviewed 28 August 2026 · We do not store the amounts you enter
Validity and privacy
- Effective from
- 1 January 2026
- Valid through
- 31 December 2026
- Privacy
- The calculation runs in your browser.
Main assumptions
- A commercial transaction between businesses, or with a public authority, covered by Spanish Act 3/2004.
- There is no different contractual late-payment rate that takes precedence.
Not included
- Consumer debts, additional damages and evidenced recovery costs above €40.
- The calculation does not by itself establish that the debt is legally enforceable.
Official sources
Frequently asked questions about B2B late-payment interest
Which rates apply in 2026?
The Spanish statutory B2B rate is 10.15% in the first half of the year and 10.40% in the second. The calculator splits the days automatically.
What is the additional €40?
Spanish Act 3/2004 gives the creditor a fixed recovery-cost amount when the debtor is late.
Does it support partial payments?
Yes. Each payment reduces the principal on which interest continues to accrue from that date.
When the estimate is not enough
We put the numbers in context.
Speak to a Numonis adviser about your specific tax, employment or financial situation.