How to Calculate Donor Attrition Rate

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Donor Attrition Rate Calculator

Calculation Results:

Donor Attrition Rate:

Donor Retention Rate:

Estimated Revenue Lost:

function calculateAttrition() { var start = parseFloat(document.getElementById('startingDonors').value); var lapsed = parseFloat(document.getElementById('lapsedDonors').value); var avgGift = parseFloat(document.getElementById('avgGift').value) || 0; var resultDiv = document.getElementById('attritionResult'); if (isNaN(start) || isNaN(lapsed) || start start) { alert("Lapsed donors cannot exceed the total number of starting donors."); return; } var attritionRate = (lapsed / start) * 100; var retentionRate = 100 – attritionRate; var revenueLost = lapsed * avgGift; document.getElementById('rateOutput').innerText = attritionRate.toFixed(2) + "%"; document.getElementById('retentionOutput').innerText = retentionRate.toFixed(2) + "%"; document.getElementById('revenueOutput').innerText = "$" + revenueLost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); resultDiv.style.display = "block"; }

Understanding Donor Attrition Rate

Donor attrition rate, often referred to as "donor churn," is a critical metric for non-profit organizations. It measures the percentage of donors who gave to your organization in a previous period (usually a fiscal year) but failed to give in the current period. High attrition rates can signal issues with donor engagement, communication strategies, or stewardship.

How to Calculate Donor Attrition

The standard formula for donor attrition is straightforward:

Attrition Rate = (Number of Lapsed Donors / Number of Donors at Start of Period) x 100

For example, if you started the year with 1,000 donors and 400 of those specific donors did not give again this year, your attrition rate is 40%.

Why Tracking Attrition Matters

In the non-profit sector, it is universally acknowledged that acquiring a new donor is significantly more expensive than retaining an existing one. High attrition forces an organization into a "leaky bucket" scenario where they must constantly spend marketing dollars just to maintain their current donor count rather than growing it.

  • Financial Impact: Every lost donor represents lost lifetime value.
  • Operational Efficiency: Improving retention by just 10% can significantly increase the compound value of your donor base over time.
  • Engagement Indicator: Sudden spikes in attrition can help you identify if a specific campaign or communication style is alienating your supporters.

Typical Benchmarks

While benchmarks vary by sector (e.g., healthcare vs. education), the average donor retention rate in the non-profit industry often hovers around 40-45%, which means the average attrition rate is 55-60%. Organizations with attrition rates lower than 50% are generally considered to have healthy donor stewardship programs.

Strategies to Lower Attrition

  1. Personalized Thank You Notes: Prompt and personal acknowledgment is the #1 factor in donor retention.
  2. Impact Reporting: Show donors exactly how their money was spent and the specific results achieved.
  3. Recurring Giving Programs: Converting one-time donors into monthly "sustainers" drastically lowers attrition rates.
  4. Surveys: Ask lapsed donors why they stopped giving to gain actionable insights into your program's weaknesses.

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