What is a contact-rate half-life?

The response time over which the chance of reaching a lead halves. It summarizes how quickly your leads go cold and lets you price each minute of delay.

How do I estimate my own half-life?

Log each lead's submission time, first contact attempt and whether it reached the borrower, bucket leads by delay, and fit the curve per source and product. Compare leads within the same hour and source, since leads that wait longer may also differ in quality.

Is exponential decay accurate for long delays?

It fits the first hours well and slightly overstates losses for delays of many hours, where the drop flattens. For staffing decisions measured in minutes to an hour it is close enough.

How fast should I respond to a loan lead?

As fast as the economics justify. Value each contact, model your own decay, and staff or automate until the next minute saved costs more than it earns.

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Speed-to-Lead Calculator

What is a minute of response time worth when contact rates decay the longer a lead waits?

Enter your lead volume and how fast you respond. The calculator estimates how many contacts, and how much revenue, you lose each month compared with responding instantly.

Leads per day500Contact rate with an instant response60%Decay half-life21 minYour average response time30 minValue per contact$40

Contact rate at your speed

22.3%

Contacts per month

3,343

Contacts lost per month

5,657

Revenue lost per month

$226,261

The default 21-minute half-life is derived from Harvard Business Review's finding that leads contacted within an hour were nearly seven times as likely to qualify as leads contacted an hour later. Exponential decay fits the first hours best and slightly overstates losses for delays of many hours. Replace the defaults with your own contact data by response time.

How it works

The chance of reaching a lead falls the longer it waits for a first call. This calculator estimates how many contacts, and how much revenue, you lose each month at your average response time compared with responding instantly. Use it to put a dollar value on faster response before deciding on staffing, queue priority or automated first touches.

Contact rate is modelled as exponential decay: it halves every fixed number of minutes, the half-life. Monthly leads (leads per day × 30) times the contact rate gives contacts; the gap between instant and actual response, times the value of a contact, is the revenue lost. The default 21-minute half-life is derived from a Harvard Business Review study in which leads contacted within an hour were nearly seven times as likely to qualify as leads contacted an hour later.

c(t) = c_0 \cdot 0.5^{\,t/h}

L = 30\,n\,\bigl(c_0 - c(t)\bigr)\,v

where

$c_0$: contact rate with an instant response
$t$: response delay, minutes
$h$: contact-rate half-life, minutes
$n$: leads per day
$v$: value of one contact
$L$: revenue lost per month

Frequently asked questions

What is a contact-rate half-life?: The response time over which the chance of reaching a lead halves. It summarizes how quickly your leads go cold and lets you price each minute of delay.
How do I estimate my own half-life?: Log each lead's submission time, first contact attempt and whether it reached the borrower, bucket leads by delay, and fit the curve per source and product. Compare leads within the same hour and source, since leads that wait longer may also differ in quality.
Is exponential decay accurate for long delays?: It fits the first hours well and slightly overstates losses for delays of many hours, where the drop flattens. For staffing decisions measured in minutes to an hour it is close enough.
How fast should I respond to a loan lead?: As fast as the economics justify. Value each contact, model your own decay, and staff or automate until the next minute saved costs more than it earns.

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