Calculator Inputs
Example Data Table
| Domain | Record | Total Resolvers | Updated | Stale | TTL (min) | Elapsed (min) | Propagation Score |
|---|---|---|---|---|---|---|---|
| example.com | A | 24 | 18 | 4 | 240 | 180 | 68.25% |
| shop.example.net | CNAME | 30 | 27 | 2 | 60 | 70 | 91.83% |
| mail.example.org | MX | 20 | 9 | 8 | 360 | 120 | 41.75% |
Formula Used
Resolver Coverage (%) = (Updated Resolvers ÷ Total Resolvers) × 100
TTL Progress (%) = min[(Elapsed Minutes ÷ TTL Minutes) × 100, 100]
Region Coverage (%) = (Updated Regions ÷ Regions Checked) × 100
Critical Coverage (%) = (Updated Critical Resolvers ÷ Critical Resolvers) × 100
Observed Pace = (Updated Resolvers − Baseline Updated) ÷ Elapsed Minutes
Estimated Remaining Minutes = (Total Resolvers − Updated Resolvers) ÷ Observed Pace
Weighted Propagation Score (%) = [Resolver Coverage × 0.45] + [TTL Progress × 0.20] + [Region Coverage × 0.15] + [Critical Coverage × 0.20] − Cache Penalty − (Unreachable Rate × 0.5)
Consistency Score (%) = 100 − [(Stale Rate × 0.7) + (Unreachable Rate × 0.8) + (Unknown Rate × 0.3)]
Confidence Score (%) = [Resolver Coverage × 0.35] + [Critical Coverage × 0.30] + [Region Coverage × 0.20] + [Consistency Score × 0.15]
This calculator uses a practical weighted model. It does not replace live resolver testing, but it helps estimate rollout maturity clearly.
How to Use This Calculator
- Enter the domain or hostname and choose the DNS record type.
- Provide the expected record value that should appear after the change.
- Fill in the number of total, updated, stale, and unreachable resolvers.
- Enter TTL and elapsed minutes since the DNS update was published.
- Add region counts and critical resolver counts for better weighting.
- Use cache penalty when you know major providers are holding older answers.
- Enter your first-check updated count and the interval between checks.
- Press Calculate Propagation to view the result summary, graphs, and output table above the form.
FAQs
1. What does the propagation score mean?
The propagation score is a weighted estimate of DNS rollout progress. It blends resolver coverage, TTL completion, regional visibility, and critical resolver adoption while reducing the score for delays and unreachable checks.
2. Why can DNS still look inconsistent after TTL ends?
Resolvers sometimes keep stale cache entries longer because of local caching rules, forwarding layers, or delayed refresh cycles. Network paths and resolver software behavior can also slow visible consistency.
3. What are critical resolvers?
Critical resolvers are high-impact DNS services that strongly affect your audience, such as major public resolvers, enterprise gateways, or large ISP recursive servers that many users rely on.
4. Is this tool performing live DNS lookups?
No. This page calculates propagation readiness from the observations you provide. It helps you interpret testing data, compare checks, and estimate remaining spread time more clearly.
5. How should I choose the cache penalty?
Use a larger penalty when you know key recursive resolvers are holding the old answer, when regional variation is severe, or when real users still report inconsistent resolution.
6. Why track regions separately?
Resolver counts alone can hide location bias. Regional tracking highlights whether an update is visible broadly or only within a few networks, continents, or datacenter clusters.
7. Can I use this for MX, TXT, and CNAME changes?
Yes. The weighting model works for common DNS record types. You only need to enter consistent resolver observations and the target value expected after the change.
8. What improves confidence score fastest?
Updating more critical resolvers and more regions usually raises confidence fastest. Reducing stale answers and unreachable checks also improves the trustworthiness of your propagation estimate.