Lead response time: why minutes matter, and what slow replies cost you

In short: the most-cited study on this topic found that companies which tried to contact a new online lead within an hour were far more likely to have a real conversation with that person than companies that waited longer. The study is old and American, so treat its exact multipliers with care. The principle, that interest fades fast, is what matters. Below is a way to calculate what slow replies cost your own business.

What the research actually found

In March 2011, Harvard Business Review published The Short Life of Online Sales Leads by James Oldroyd, Kristina McElheran and David Elkington. It combined two pieces of work:

1. An audit of 2,241 US companies that were sent test enquiries through their websites. 37% responded within an hour, 16% within one to 24 hours, 24% took longer than 24 hours, and 23% never responded at all. Among companies that did respond, the average response time was 42 hours.
2. An analysis of 1.25 million sales leads received by 42 US companies. Firms that tried to contact a lead within an hour were nearly seven times as likely to qualify it (have a meaningful conversation with a decision-maker) as firms that tried an hour later, and more than 60 times as likely as firms that waited 24 hours or longer.

What the research does not prove

Be careful with how these numbers are repeated online. Many articles round them into claims the study never made, or attach other studies' figures to Harvard's name.

The data is from US companies and is more than a decade old. Customer expectations have arguably become faster since, not slower, but we do not have equally rigorous recent data to put a precise number on it. Use the research for its direction, not as a forecast for your business.

Why speed matters more for some businesses

Speed matters most when:

• The customer is comparing several providers at once. A dental patient abroad might contact five clinics in one evening. The first useful reply sets the reference point for every other one.
• The decision is emotional or urgent. Someone with a leaking roof or a toothache wants an answer now.
• Enquiries arrive outside office hours. Evenings and weekends are when many people finally have time to research big decisions.

It matters less for slow, committee-led purchases where nobody expects a reply the same day.

Calculate what slow replies cost you

You do not need industry averages. You need four numbers from your own business:

Now make one honest assumption: E, the share of out-of-hours enquiries you lose because you reply too late. Look at your own data if you can: of the enquiries that arrived at night and were answered the next day, how many never replied or booked elsewhere? If you cannot measure it yet, try a cautious figure such as 15%.

The monthly value at risk is:

Value at risk = A × B × E × C × D

With the example numbers:

120 × 0.35 × 0.15 × 0.20 × 900 = €1,134 per month

That is about €13,600 a year, from one business, from one gap. Change the inputs to your own and the result is a number you can compare directly with the cost of fixing it.

How to close the gap

1. Measure first. For one month, log when each enquiry arrives and when it gets its first real reply. Most businesses are surprised by the result.
2. Reply instantly, even if you cannot answer fully. An immediate acknowledgement that answers the common questions and books a call keeps the customer engaged.
3. Cover every channel. Website forms, email, WhatsApp, Viber and missed calls all need the same speed.
4. Hand over to a human quickly. Automation should start the conversation, not replace your team.
5. Track the result. Compare conversion rates before and after, using the same calculation above.

An AI enquiry assistant can handle steps 2 to 4 around the clock, in your customer's language, while always making clear that it is an assistant. That is exactly what we build in AI enquiry handling.