Why We Built a Free Late Payment Interest Calculator (No Email Required)

It's a Chrome extension. It's free. It calculates late payment interest on B2B invoices in seconds.

What it does NOT require:

• Email address
• Signup
• Company details
• Credit card (even for a "trial")
• Booking a demo
• Talking to our sales team

What it DOES require:

• Invoice amount
• Invoice date
• Due date
• Currency

You enter those four things. You get a number. That's it.

Get it here: Chrome Web Store

Most B2B Suppliers Don't Claim Late Payment Interest

Not because they don't want the money. Not because they're not entitled to it. Because calculating it is annoying.

We talk to hundreds of B2B suppliers every month. Most of them:

• Know they can charge interest
• Don't know how much they're owed
• Don't calculate it because it's tedious
• Write off the interest (but not the principal) to avoid the hassle

That's leaving money on the table.

Existing Tools Are Gatekeepers

When we Googled "late payment interest calculator," we found:

• Law firm calculators: Require your contact details "for audit purposes" (translation: for their mailing list)
• SaaS tools: Free tier shows you the first €100 of interest, then upsells you to Pro
• Accounting software add-ons: Require subscribing to the whole accounting platform
• Excel templates: From 2011, using outdated interest rates, with broken formulas

None of them just... gave you the number.

They all wanted something first. Your email. Your company name. A meeting. A subscription.

We Had the Formula Already

At Collecty, we calculate late payment interest all the time. It's part of what we do when recovering unpaid B2B invoices.

We have the formulas. We know the regulations (EU Late Payment Directive, UK rules, custom contract rates). We've built the logic.

Why not package it as a tool anyone can use?

Scenario 1: Payment Reminder Emails

Before:

"Your invoice of €47,000 is now 92 days overdue. Please pay immediately."

After:

"Your invoice of €47,000 is now 92 days overdue.
Late payment interest accrued: €3,847
Total amount due: €50,847
Please pay immediately."

Specificity increases urgency. Clients are more likely to prioritize invoices with quantified interest.

Scenario 2: Internal Escalation

Your finance director asks: "How much are we owed across all overdue invoices?"

Without the calculator: "Um, about €200K principal... not sure about interest."

With the calculator: "€203,450 principal, €18,920 in accrued interest. Total: €222,370."

Scenario 3: Write-Off Decisions

Your accountant wants to know if an overdue invoice is worth pursuing.

• Principal: €12,000
• Days overdue: 180
• Interest: €2,160
• Total: €14,160

If your collection cost is €1,500, the interest covers it. Worth pursuing.

If your collection cost is €3,000, the interest doesn't cover it. Write off or negotiate.

Scenario 4: Demand Letters Before Legal Action

Before engaging a collection agency or lawyer, you send a final demand.

Including the calculated interest (with daily accrual rate) signals:

• You're tracking this precisely
• The amount owed is increasing daily
• You're serious about recovery

We're Not a SaaS Company

Collecty is a B2B debt collection agency. We recover unpaid invoices when reminders don't work.

We don't make money from software subscriptions. We make money when we successfully recover debts.

So the calculator is free because:

1. If you calculate the interest and get paid → Great, we helped. You don't need us.
2. If you calculate the interest and still don't get paid → You know exactly what to ask us to recover.

We don't need your email to know you have late payment problems. The overdue invoice tells us that.

We Don't Capture Emails

Most "free tools" are lead magnets. You give your email, you get the tool, you're added to a mailing list.

We skipped that.

If you use our calculator and later decide you need debt collection help, you'll remember who built the free tool. If you don't, that's fine too.

We're not going to spam you into using our services.

1. Go to the Chrome Web Store
2. Search: "Late Payment Interest Calculator"
3. Click "Add to Chrome"
4. Open the extension whenever you need to calculate interest

No account. No registration. No credit card "for verification."

Direct link: Chrome Web Store

Late Payment Is a €200 Billion Problem in Europe

Every year, European SMEs are owed approximately €200 billion in overdue invoices. Most of it is eventually paid, but late.

The cost:

• Cash flow strain
• Opportunity cost (money tied up in receivables)
• Administrative burden (chasing payments)
• Interest loss (money you could have earned or invested)

Late payment interest exists to compensate for these costs. It's not punitive — it's compensatory.

But if suppliers don't calculate and claim it, they bear the cost while clients face no penalty for paying late.

Legal Frameworks Support This

The EU Late Payment Directive (2011/7/EU) and similar laws in the UK, US, and other jurisdictions explicitly grant suppliers the right to charge interest on late B2B payments.

You don't need a contract clause. It's statutory.

But legal rights are only useful if you exercise them. And you can't exercise them if you don't know how much you're owed.

If a customer is 90 days late on a €47,000 invoice, you should know exactly what that's costing you.

Before your next coffee, not your next board meeting.

We built the tool. We put it on the Chrome Web Store. We didn't ask for your email.

Because late payment interest shouldn't require a sales call.

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Get the calculator: Late Payment Interest Calculator — Chrome Web Store

Need help recovering unpaid invoices? Collecty specializes in B2B debt recovery across 160+ countries. 80%+ success rate. No win, no fee.

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