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      How To Calculate QPS Limit for Campaign Budget Control

      Implementing QPS Limit Calculation for Campaign Budget Control

      Content

      Overview

      QPS (Queries Per Second) limits help control campaign spending by restricting the number of bid requests your campaign can participate in per second. This is essential for budget management, especially when you have high traffic volume but low hourly or daily budget caps.

      When to Use QPS Limits

      QPS limits are typically needed when:

      • High traffic volume campaigns receive many bid requests
      • Low hourly or daily caps require tight budget control
      • Fast spending campaigns need pacing throughout the hour
      • Budget overrun protection is critical for campaign success

      Example scenario: The campaign receives 1,000+ requests per second but has a $50/hour budget cap.

      QPS Calculation Formula

      Required Information:

      1. Bid Price (CPM in USD)
      2. Fill Rate (percentage of requests that become impressions)
      3. Desired Hourly Spend (maximum budget per hour in USD)

      Step-by-Step Calculation:

      Step 1: Calculate Cost Per Impression 

      Cost Per Impression = Bid Price ÷ 1000

       

      Step 2: Calculate Effective Cost Per Request

      Cost Per Request = Cost Per Impression × Fill Rate

       

      Step 3: Calculate Allowed Requests Per Hour

      Requests Per Hour = Hourly Spend ÷ Cost Per Request

       

      Step 4: Calculate QPS Limit

      QPS Limit = Requests Per Hour ÷ 3600

      Practical Example

      Campaign Details:

      • Bid Price: $1.80 CPM
      • Fill Rate: 15% (0.15)
      • Hourly Budget: $20

      Calculation:

      Step 1: Cost per impression

      $1.80 ÷ 1000 = $0.0018 per impression

       

      Step 2: Effective cost per request

      $0.0018 × 0.15 = $0.00027 per request

       

      Step 3: Allowed requests per hour

      $20 ÷ $0.00027 = 74,074 requests/hour

       

      Step 4: QPS limit

      74,074 ÷ 3600 = 20.6 QPS

       

      Result: Set QPS limit to 21 QPS

      Implementation Guidelines

      Setting QPS in Campaign Capping

      1. Calculate QPS using the formula above
      2. Round up to the nearest whole number for a safety margin
      3. Set QPS limit in the campaign's Capping tab
      4. Monitor spend pacing after implementation

      Monitoring and Adjustment

      Watch for:

      • Underspend: QPS too low, increase limit gradually
      • Overspend: QPS too high, decrease limit
      • Fill rate changes: Recalculate when performance shifts

      Common QPS Ranges

      • Low volume campaigns: 1-10 QPS
      • Medium volume campaigns: 10-50 QPS
      • High volume campaigns: 50-200+ QPS
      • Premium campaigns: May require 500+ QPS

      Best Practices

      Initial Setup

      • Start conservative: Use calculated QPS or slightly lower
      • Monitor closely: Watch spend pacing for the first few hours
      • Adjust gradually: Make small QPS changes (±10-20%)

      Ongoing Management

      • Recalculate regularly: When bid prices or fill rates change
      • Consider time zones: Peak hours may need different limits
      • Account for weekends: Lower fill rates may require QPS adjustments

      Troubleshooting

      The campaign is not spending enough:

      • Increase QPS limit by 25-50%
      • Check if the fill rate assumptions are accurate
      • Verify the bid price is competitive

      Campaign overspending:

      • Decrease QPS limit by 10-25%
      • Consider tighter hourly caps
      • Review if the fill rate is higher than expected

      Advanced Considerations

      Multiple Time Zones

      For global campaigns, consider peak traffic hours and adjust QPS accordingly.

      Seasonal Variations

      Fill rates and bid competition change seasonally - recalculate QPS quarterly.

      Campaign Performance

      Higher-performing campaigns may achieve better fill rates, requiring QPS recalculation.