Dunning Email ROI Calculator

See exactly how much additional revenue a dunning email sequence can recover from your failed payments.

Dunning emails are automated messages sent to customers after a payment fails, prompting them to update their payment method. This calculator shows the revenue impact of improving your dunning email recovery rate. Since email sending costs are essentially zero when you use your own SMTP (like with Rezoki), the ROI is nearly infinite.

Your Numbers

$

Total number of payment failures per month.

$

Average dollar amount of each failed invoice.

%

What percentage of failed payments do your current emails recover? 0% if you have no dunning emails.

%

Expected recovery rate with an optimized email sequence. Good sequences achieve 35-50%.

Results

Monthly Revenue at Risk

$6,500

Current Monthly Recovery

$975

Target Monthly Recovery

$2,600

Additional Revenue/Month

$1,625

Annual Additional Revenue

$19,500

Email Sending Cost

$0

Formula

Additional Revenue = Failed Payments x Avg Invoice x (Target Rate - Current Rate)

The calculator multiplies the number of monthly failed payments by the average invoice value to get total revenue at risk. It then applies both your current and target recovery rates to find the gap — that gap is the additional revenue you would recover each month. Since Rezoki uses your own SMTP for sending (zero marginal cost), the net gain equals the gross gain. Annual projections simply multiply by 12.

How to Interpret Your Results

Low Volume

Under $500/mo additional

The absolute number is small, but dunning emails cost nothing to send. Free revenue is still worth capturing.

Meaningful

$500-$3,000/mo additional

This is real money. A well-crafted 4-email sequence could fund a significant portion of your tool stack.

Substantial

$3,000-$15,000/mo additional

Your dunning emails could be recovering the equivalent of several new customers worth of revenue each month.

Game-Changing

Over $15,000/mo additional

The revenue impact of optimized dunning is massive for your business. This warrants dedicated attention.

Industry Benchmarks

SegmentBenchmarkContext
No dunning emails0-5% email recoveryRelying solely on payment retries. Customers never know their payment failed.
Single dunning email10-15% email recoveryOne email helps but many customers miss it or procrastinate.
Multi-email sequence (3-5 emails)25-40% email recoveryA proper sequence with escalating urgency recovers significantly more.
Multi-channel (email + voice + in-app)50-70% total recoveryAdding voice calls and in-app notifications to email sequences maximizes recovery.

How Rezoki Can Improve These Numbers

Rezoki is an AI-powered revenue recovery platform purpose-built for SaaS. It combines smart payment retries (timed for maximum approval rates), personalized dunning email sequences, and AI voice calls to recover failed payments before they become permanent churn.

  • Average 70% recovery rate across all customers
  • 5-minute integration with Stripe — no engineering needed
  • Uses your own SMTP for zero-cost email delivery
  • AI voice calls for high-value invoices that need a personal touch

Related Tools

Frequently Asked Questions

How many dunning emails should I send?+
Best practice is 4-6 emails over a 14-21 day period. Start with a friendly notification within hours of the failure, follow up at day 3 and day 7, then escalate urgency with "last chance" messaging before the subscription is canceled. Rezoki configures this automatically.
What should a dunning email say?+
Keep it simple and non-threatening. Subject line should mention the payment issue. Body should explain what happened, provide a one-click link to update payment, and mention what happens if unresolved (service interruption). Avoid blame language — this is usually not the customer's fault.
Do dunning emails annoy customers?+
No — data consistently shows customers appreciate being notified about payment issues. Most people are unaware their payment failed. A well-written dunning email is a customer service moment, not spam. Recovery rates of 40%+ prove customers want to fix the issue.
Why is the cost of dunning emails effectively zero?+
When using your own SMTP server (which Rezoki supports natively), the marginal cost of sending an email is fractions of a cent. Even dedicated email services charge $0.001 or less per email. At 500 emails/month, the cost is under $1. The revenue recovered dwarfs this.
How does email-based dunning compare to AI voice calls?+
Email typically recovers 25-40% of failed payments. Adding AI voice calls on top of email recovers an additional 15-25%, bringing total recovery to 50-70%. Voice calls are especially effective for higher-value invoices where a personal touch makes the difference.

Stop Losing Revenue to Failed Payments

Rezoki recovers failed payments automatically with AI-powered emails and voice calls. Set up in 5 minutes.