Free email marketing calculators: know your numbers before you send
No spreadsheet. Enter your own figures and get the answer, with the formula shown.
These email calculators turn your own numbers into the figures that decide a campaign: bounce and open rates, how many inboxes a cold email volume needs, a warmup schedule, how fast a list decays and what outbound returns. Each shows its formula, so you can check the maths or rebuild it in a spreadsheet.
The inputs are yours and the formulas are standard, but the benchmarks they are read against come from the providers' own published limits, cited on each page. Where a number is a rule of thumb rather than a published limit, the page says so.
19 email marketing calculators
Verification cost calculator
Compare what verifying a list costs per 1,000 addresses across 34 vendors' published prices, including what re-verifying costs again.
Cold email inbox calculator
Enter your daily target and per-inbox limit to get inboxes, domains, warm-up time and monthly volume, checked against Google's published limits.
Bounce rate calculator
Enter sent, bounced and complaints to get your rates, checked against each platform's published suspension line and Google's complaint threshold.
Email verification cost by list size
Your list size and how often you check it, priced at SimpleVerifier and 8 other verifiers from their own pricing pages, lowest first, with a link to each.
Sending limits calculator
Pick Gmail, Google Workspace, Microsoft 365 or Outlook.com to see every published daily and per-email limit, which one caps you, and how many inboxes your volume needs.
Cold email ROI calculator
Turn prospects, reply, meeting and close rates, deal size and costs into monthly revenue, ROI and cost per meeting, plus the revenue lost to bounced addresses.
Open rate calculator
Open rate on delivered mail, click-through and click-to-open rates, and the rate without Apple's automatic opens, beside published averages with their sources.
Email warm-up calculator
Enter inboxes, target volume and step size and get a week-by-week warm-up ramp per inbox and in total, with Google's no-doubling rule built in.
Email list decay calculator
Enter list size and age and pick a yearly rate (a BLS job-tenure model by role, or your own measured rate) to estimate how many contacts have gone stale.
Spam complaint rate calculator
Complaints ÷ delivered, checked against Google's 0.1% target and the 0.3% limit in Google's and Yahoo's sender rules, with the complaint budget for your next send.
SMS cost calculator
Recipients × messages × segments × per-segment price plus carrier fees, with the segment count from your actual text and the cost of unreachable numbers.
Email A/B test calculator
A two-proportion z-test on reply, open or click rates: p-value, lift and confidence interval, plus the sends each variant needs before a test is worth reading.
List growth rate calculator
New subscribers minus unsubscribes, hard bounces, complaints and other removals, divided by the starting list size: the growth rate per period, compounded to a year, with the formula shown.
Email marketing ROI calculator
Revenue from email (known, or estimated from sends, bounce, click and conversion rates) against platform and other costs: ROI, return per $1, revenue and cost per subscriber.
Cost per lead calculator
Enter spend and leads for each source, plus the share with invalid emails and duplicates, to get cost per lead, cost per valid lead and the spend lost on leads you can't reach.
Call center staffing calculator (Erlang C)
Enter calls per interval, average handle time and a service-level target to get the agents needed on the phones by Erlang C, the number to schedule after shrinkage, and the wait, ASA and occupancy at each staffing level.
Best time to send email calculator
Paste recipient time zones, cities or US/Canada phone numbers, pick the local time mail should arrive, and get a batch schedule in your own time zone, with daylight saving handled.
TAM calculator
Enter the accounts that fit your customer profile, contacts per account and your daily send volume to get TAM, SAM and SOM, the reachable list size and its runway in months.
Cold email bounce cost calculator
Estimated bounces a day and per inbox, the published 2% to 10% platform lines before and after verification, and the cost to verify the list at SimpleVerifier and other verifiers.