Bounce bill calculator
Estimate what dirty email data costs every month
Compare verification costs, estimate wasted sends, and choose when list cleaning pays for itself before campaigns, imports, or signup traffic scale up.
Estimate the damage
At 4% across 100,000 monthly checks.
Direct sending waste only; reputation damage can cost more.
Estimated at $75 per 10k checks.
Pro, covering 100,000 credits.
Risk status: Needs attention. Verify before the list reaches your sender, CRM, or signup flow.
The math behind your bounce bill
Start with your list size and an estimated bad-address rate. If you send to 100,000 contacts and 12% are invalid, that is 12,000 messages sent to addresses that will never open, on top of whatever your platform charges to send them. The direct waste is bad addresses x cost per send. Verification flips that equation: paying a small per-address fee up front removes those 12,000 before you ever send.
The calculator compares the two paths, the cost of sending to a dirty list versus the cost of cleaning it first, so you can see the break-even point instead of guessing.
The costs that are easy to miss
The per-send charge is only the visible line item. A high bounce rate also damages your sender reputation, which lowers inbox placement for the valid addresses too, quietly cutting the revenue from your good contacts. Mailbox providers treat elevated bounces and spam-trap hits as signals to throttle or block a sender, and recovering reputation is slow and expensive.
There is opportunity cost as well: staff time spent chasing deliverability problems, and campaigns that underperform because they landed in spam. These indirect costs frequently dwarf the raw per-send waste, which is why cleaning usually pays for itself well before the naive break-even.
When verification clearly pays off
Verification wins fastest on large lists, lists with unknown or aging provenance, and any list feeding a reputation-sensitive channel like cold outreach. The dirtier the list and the higher your per-send cost, the sooner cleaning beats sending as-is. On small, freshly opted-in lists the margin is thinner, though the reputation protection still favors verifying.
To act on the number, verify the list with the Verifly API at https://verifly.email/api/v1, which returns disposable, role, catch-all, and SMTP flags per address, and dedupe first with the email list deduplicator so you never pay to verify the same address twice. New accounts get 100 free credits.
Frequently asked questions
How is the bounce bill calculated?
It multiplies your list size by an estimated bad-address rate to get the number of wasted sends, then applies your per-send cost. It compares that to the cost of verifying the list up front so you can see which path is cheaper and where they break even.
What bad-address rate should I assume?
It varies by list. Fresh, opted-in lists may be a few percent invalid, while old, purchased, or scraped lists can run 20% or higher. If you are unsure, model a range: the calculator shows how sensitive the cost is to that rate.
Why do bounces cost more than the wasted send fee?
A high bounce rate signals poor list hygiene to mailbox providers, which lowers inbox placement for your valid contacts too. That reputation damage reduces the revenue from good addresses and can get your domain throttled, costs that usually exceed the raw per-send waste.
When does verification pay for itself?
Sooner the larger and dirtier the list and the higher your per-send cost. For big lists with unknown provenance, verification typically costs far less than the sends it prevents, before you even count the reputation savings. Small, clean lists have a thinner margin.
Does deduplicating change the numbers?
Yes. Duplicates inflate both your send count and your verification cost. Removing them first, which is free, means the bad-address rate and per-address verification fee apply only to unique contacts, improving every figure in the estimate.
How do I actually clean the list after seeing the number?
Verify the list through the Verifly API with a vf_ Bearer key or in the dashboard. GET /verify?email= returns disposable, role, catch-all, and SMTP flags per address, letting you drop the bad ones before you send and pay for.