Calculator Inputs
Enter your audit findings, then calculate a weighted authentication score for sender trust, enforcement strength, reporting maturity, and impersonation resistance.
Example Data Table
| Domain | SPF | DKIM | DMARC Policy | Coverage | Score | Grade |
|---|---|---|---|---|---|---|
| alpha-mail.com | Pass | Pass | Reject | 100% | 94.00 | A |
| growth-campaign.io | Softfail | Pass | Quarantine | 82% | 72.20 | C |
| legacy-sender.net | Fail | Partial | None | 55% | 38.50 | F |
Formula Used
This calculator converts email authentication audit findings into a weighted score out of 100. Higher values indicate stronger impersonation resistance, better alignment, and more mature enforcement.
| Component | Rule | Max Points |
|---|---|---|
| SPF status | Pass = 15, Softfail = 8, Neutral = 4, Fail = 0 | 15 |
| SPF lookup budget | 5 points when lookups are 10 or less; lose 1 point for each lookup above 10 | 5 |
| SPF alignment | Strict = 5, Relaxed = 4, Fail = 0 | 5 |
| DKIM status | Pass = 20, Partial = 10, Fail = 0 | 20 |
| DKIM key strength | 4096-bit = 10, 2048-bit = 8, 1024-bit = 4, weaker = 0 | 10 |
| DKIM alignment | Strict = 5, Relaxed = 4, Fail = 0 | 5 |
| DMARC policy | Reject = 15, Quarantine = 10, None = 4, Missing = 0 | 15 |
| DMARC coverage and pct | Coverage × 0.10 and pct × 0.05 | 15 |
| TLS, BIMI, reporting, subdomain policy | TLS = 3, BIMI = 2, RUA = 2, RUF = 1, sp= = 2 | 10 |
Total Score = SPF status + SPF lookup budget + SPF alignment + DKIM status + DKIM key strength + DKIM alignment + DMARC policy + DMARC coverage + DMARC pct + TLS + BIMI + RUA + RUF + subdomain policy.
How to Use This Calculator
- Enter the sending domain and the DKIM selector you are testing.
- Choose the observed SPF, DKIM, and DMARC outcomes from your audit or monitoring tool.
- Enter numeric values for SPF lookups, DMARC coverage, and DMARC pct enforcement.
- Mark whether TLS, BIMI, reporting, and subdomain policies are present.
- Click the calculate button to view the score, grade, chart, and remediation priorities above the form.
FAQs
1) What does this calculator measure?
It measures how strong your email authentication program appears based on SPF, DKIM, DMARC, alignment, reporting, encryption, and policy coverage. The output helps prioritize improvements and compare sender configurations consistently.
2) Why can SPF pass but the score still be weak?
A passing SPF result alone is not enough. Too many DNS lookups, failed alignment, weak DMARC policy, missing reports, or poor coverage can still leave a domain vulnerable to spoofing and inconsistent enforcement.
3) Why is DKIM key length included?
Key length reflects signing strength. A 2048-bit key is a common modern baseline, while shorter keys offer less confidence. Stronger DKIM keys improve resilience and support more trustworthy authentication posture assessments.
4) What does DMARC pct change in practice?
The pct tag controls how much mail the receiving side applies the DMARC policy to. Lower values soften enforcement during rollout. Higher values indicate broader protection and greater confidence in sender inventory accuracy.
5) Is a reject policy always the best choice?
Reject is strongest when your mail streams are fully inventoried and aligned. If legitimate traffic still fails, a reject policy can block wanted mail. Quarantine is often a safer transition step before full enforcement.
6) Does BIMI improve security directly?
BIMI mainly improves brand presentation and trust signaling. It does not replace SPF, DKIM, or DMARC. It becomes most useful after strong DMARC enforcement is already working correctly and consistently.
7) Can this replace a live DNS audit?
No. This tool scores the audit findings you provide. A live DNS review is still necessary to inspect actual records, vendor paths, syntax issues, selector behavior, and sending source coverage across all environments.
8) How often should teams retest email authentication?
Re-test after onboarding new vendors, changing gateways, rotating DKIM selectors, editing DNS, or shifting mail routing. Quarterly reviews are a practical baseline for mature environments, while active migrations may need weekly checks.