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Find the leak in your donor base.
Two instruments, one discipline. If you run a monthly giving program, measure your sustainer churn. If your donors give once a year, size your LYBUNT and SYBUNT reactivation list. A few numbers from memory, computed in your browser, sent nowhere unless you ask.
Your numbers
Computed in your browser. Nothing is stored or sent unless you request the report.
The readout
estimate · not auditedThe readout appears as you type.
start with your active sustainer count, or try the sample numbers
Methodology
An estimate that tells you it's an estimate.
Most donor calculators hand you a confident number built on hidden assumptions. These publish their formulas, label every assumption on the readout, and refuse to show a sector benchmark they can't stand behind. That discipline (incomplete beats wrong) is the same one behind the member benchmark.
- Retention mode
- For monthly programs: estimated churn = lapsed ÷ (active + lapsed) over your trailing 12 months, split into voluntary (they chose to stop) and involuntary (a card failed, the recoverable kind). If you don't know the split, we show an illustrative 45% and label it assumed.
- Reactivation mode
- For annual donors: repeat retention = donors who gave again ÷ donors who gave last year. LYBUNT = gave Last Year, But Unfortunately Not This, your warmest lapsed list. SYBUNT = gave Some earlier Year but not since, a colder, separate pool.
- Acquisition-cost mode
- For pricing cold outreach: staff cost = salary × 1.25 (benefits, labeled assumed) ÷ 2,080 hours, times your outreach hours across 48 weeks. Your retention compares against the AFP Fundraising Effectiveness Project's 2025 overall rate (43.3%). Their data, your numbers; nothing invented in between.
- It's an estimate
- Both modes compute from totals you can recall, so they're directional and not audited. They can't dedupe donors, weight by gift size, or perfectly separate cohorts. Dollar figures are an opportunity at prior giving levels, not a promised recovery.
- What the member version adds
- The concierge run computes the audited numbers from your actual gift export: cohorts kept separate, upgrades and migrations censored out, and a reliability gate that suppresses any number too distorted to trust.
- Why the benchmark is locked
- Sector medians publish only when at least 7 organizations and 200 donors are pooled. Below that, a median is statistically thin and potentially identifiable. Incomplete beats wrong.
You've seen the estimate. Members get the audited number.
The concierge run measures your retention exactly from your own records, and your sector's training track teaches you how to close the leak it finds.