Free Email Deliverability Tool • Browser-Only
Gmail, Yahoo and Outlook Bulk Sender Compliance Checker
Enter your daily email volume and current authentication setup to check whether your root domain triggers the 5,000-message bulk sender rules at Gmail and Outlook.com, calculate your exact daily spam complaint budget at 0.10% and 0.30%, and generate a prioritized fix checklist. All calculations run in your browser with full working shown.
By Hamza Rivera, updated
Short answer: Google and Microsoft classify a domain as a bulk sender when it sends 5,000 or more messages in 24 hours across the root domain and all subdomains combined, while Google and Yahoo require user-reported spam rates to stay below 0.10% and never reach 0.30% (1 and 3 complaints per 1,000 delivered emails). Use this browser-based checker to calculate your daily complaint budget and audit SPF, DKIM, DMARC, alignment and RFC 8058 one-click unsubscribe headers.
Need a human audit of your live DNS records, Postmaster Tools and blocklists? See our Email deliverability fix service, read our Gmail and Yahoo sender requirements guide, or build your TXT records in the SPF and DMARC record generator.
1. Daily sending volume & complaint calculator
Google counts messages to personal Gmail accounts across your primary root domain and all subdomains combined over a 24-hour window. Microsoft applies its consumer Outlook.com rules above 5,000 messages per day.
2. Technical authentication & header checklist
Select your current domain configuration to evaluate compliance against Google, Yahoo and Microsoft consumer mailbox rules.
How the bulk sender and complaint formulas work
Every figure in the calculator above is computed directly from the published thresholds in Google’s Email Sender Guidelines, Yahoo’s Sender Hub and Microsoft’s Outlook.com high-volume sender documentation. No hidden scoring weights are used.
| Metric | Formula | Published provider rule (read Nov 9, 2026) |
|---|---|---|
| Aggregated 24-Hour Root Domain Volume (Gmail & Outlook Trigger) | Total_Root_Volume = Primary_Domain_Daily_Messages + Subdomain_Daily_Messages | If Total_Root_Volume >= 5,000 messages/day to Gmail or Outlook.com, bulk sender authentication (SPF + DKIM + DMARC + alignment + RFC 8058 one-click unsubscribe) is mandatory. At Gmail, crossing this threshold once classifies the root domain as a bulk sender permanently. |
| Gmail Safe Daily Complaint Budget (< 0.10% Target) | Max_Safe_Complaints_Per_Day = floor(Daily_Delivered_Messages * 0.001) | Google Postmaster Tools requires senders to keep user-reported spam rates below 0.10% (0.001). At 5,000 delivered messages/day, 5 complaints equal 0.10%, so staying strictly below 0.10% allows at most 4 user spam reports per day. |
| Gmail & Yahoo Enforcement Ceiling (0.30% Fault Threshold) | Enforcement_Ceiling_Complaints_Per_Day = ceil(Daily_Delivered_Messages * 0.003) | At or above 0.30% (0.003), both Google and Yahoo classify the spam rate as impaired. At Google, a spam rate at or above 0.30% makes a sender ineligible for mitigation until the rate stays below 0.30% for 7 consecutive days. |
| Observed User Spam Complaint Rate (%) | Observed_Spam_Rate_Pct = (Daily_User_Complaints / Daily_Delivered_Messages) * 100 | Calculated over delivered messages that recipients can mark as spam in the inbox (messages rejected at SMTP or routed directly to the Spam folder do not register user "Report spam" clicks in Postmaster Tools). |
Gmail, Yahoo and Outlook.com requirements compared
While all three mailbox providers rely on SPF (IETF RFC 7208), DKIM (RFC 6376) and DMARC (RFC 7489), their bulk volume definitions and enforcement actions differ. For a plain-English walkthrough of what small businesses need to do, read our Gmail and Yahoo sender requirements guide.
| Mailbox Provider | Bulk Volume Trigger | Authentication & Alignment | Spam Rate Ceiling | Unsubscribe Rule & Primary Source |
|---|---|---|---|---|
| Google (Personal Gmail) | Close to 5,000 or more messages in a 24-hour window to personal Gmail accounts, counted across the primary root domain and all subdomains combined. Permanent classification once reached. | All senders: SPF or DKIM. Bulk senders: both SPF and DKIM required, plus a valid DMARC record (at least p=none) and From: header alignment with SPF or DKIM. | Keep user-reported spam rate in Google Postmaster Tools below 0.10% (1 complaint per 1,000 delivered messages) and never reach or exceed 0.30% (3 complaints per 1,000). | Required for commercial and promotional bulk messages: RFC 8058 List-Unsubscribe-Post and List-Unsubscribe headers covered by DKIM, plus a visible body unsubscribe link honored within 48 hours. Google Workspace Admin Help (answer/81126 & answer/14229414), read Nov 9, 2026 |
| Yahoo Mail (Yahoo & AOL) | Yahoo Sender Hub applies bulk requirements to promotional and high-volume mail streams without publishing a fixed 5,000-message numeric floor on the best-practices page. | All senders: SPF or DKIM. Bulk senders: both SPF and DKIM required, a valid DMARC policy (at least p=none) that passes, and From: alignment. | Maintain user-reported spam complaint rate below 0.30% (3 complaints per 1,000 messages). | Support one-click List-Unsubscribe headers on promotional mail, include a clear visible opt-out link, and honor unsubscribe requests within 48 hours. Yahoo Sender Hub Best Practices (senders.yahooinc.com/best-practices/), read Nov 9, 2026 |
| Microsoft Consumer (Outlook.com, Hotmail, Live.com) | Domains sending more than 5,000 emails per day to consumer Outlook.com family addresses. Non-compliant mail routed to Junk starting May 5, 2025, with outright rejection scheduled later. | Must pass SPF, pass DKIM, and publish a DMARC record (at least p=none) that aligns with SPF or DKIM (preferably both). | High complaint rates and invalid recipient bounces degrade sender reputation in Microsoft SNDS and trigger Junk routing or throttling. | Provide a clear, visible way to opt out of promotional and bulk messages and process opt-outs promptly. Microsoft Defender for Office 365 Blog (high-volume sender requirements), read Nov 9, 2026 |
Related email deliverability guides and services
- Email deliverability fix service (Offer A: single domain, Offer B: cold email audit)
- Gmail and Yahoo sender requirements, explained for small businesses
- Free SPF & DMARC TXT record generator and 10-lookup checker
- SPF, DKIM and DMARC in plain English
- Cold email infrastructure checklist for agencies and B2B teams
- Why business emails go to spam
Questions about bulk sender compliance and spam rates
Does using a subdomain for marketing or cold email reset the 5,000-message Gmail limit?
No. Google’s Email Sender Guidelines FAQ states that the 5,000-message daily count is aggregated across the primary root domain and all of its subdomains combined. Once a root domain crosses the bulk threshold at Gmail, Google treats it as a bulk sender permanently.
How many spam complaints per day put a 5,000-email sender over Gmail’s limit?
At 5,000 delivered messages per day, a 0.10% spam rate is 5 complaints (5,000 * 0.001 = 5), and the 0.30% enforcement ceiling is 15 complaints (5,000 * 0.003 = 15). To stay strictly under 0.10%, a 5,000-message daily sender can tolerate at most 4 user spam clicks per day.
What is the difference between a visible unsubscribe link and RFC 8058 one-click unsubscribe?
A visible unsubscribe link is an HTML link inside the email body that recipients can read and click. RFC 8058 one-click unsubscribe consists of two machine-readable email headers (List-Unsubscribe and List-Unsubscribe-Post: List-Unsubscribe=One-Click) signed by DKIM so Gmail and Yahoo can render an "Unsubscribe" button next to the sender name at the top of the message.
Do transactional emails such as invoices and password resets require RFC 8058 one-click headers?
No. Google’s sender guidelines require one-click unsubscribe only for commercial, promotional and marketing messages. Transactional messages such as receipts, invoices and account alerts are exempt from the one-click unsubscribe requirement, though they still require SPF, DKIM, DMARC and alignment if sent from a bulk domain.
Does this checker query or store my domain data?
No. Every calculation runs locally in your browser using JavaScript. If you want the Passieon Team to inspect your live DNS records and blocklist status, you can request a free manual check using the form on this page.