Missed Call Cost Calculator for Landlords

The formula

For a single missed call, a reasonable estimate is:

Missed call cost = (extra void days) × (daily rent)
                  + (extra repair cost from a delayed report, if any)

• Extra void days — for a prospective tenant, this is roughly the time until they'd have moved in had the call been answered; for an existing tenant reporting an issue, it's the delay before the problem is reported and resolved, which can itself extend the void period at the end of a tenancy if the issue is left to worsen.
• Daily rent — monthly rent divided by 30.
• Extra repair cost — the difference between fixing something early and fixing it after it's had time to get worse (a small leak vs. water damage, for example).

A worked example

Across a portfolio of even a handful of properties, a few missed calls a month at these figures adds up to a meaningful amount of lost rent — well beyond what most landlords would guess before running the numbers. Want to see how this looks for your own property? The calculator further down this page lets you adjust each figure and see the estimate update as you go.

The psychology behind the number

The formula above treats a missed call as a bookkeeping problem, but the behaviour behind it is well studied, and it argues for taking "I'll call them back later" less lightly than it feels in the moment.

UK letting and estate agents are already slow to respond, and prospective tenants notice. Mystery-shopper research by Homeflow covering UK agencies found that only 70% of rental enquiries got a reply at all, just 40% of agents responded within an hour, and the average response time across the market ran to around 229 business minutes — the best part of a working day. A prospective tenant weighing up several properties at once doesn't necessarily wait for a same-day reply; they've often moved on to whichever property answered first.

A missed call is a bad service experience, and those register strongly. A 2019 neuromarketing study co-authored out of the University of Dundee and a London research firm, published in Behavioral Sciences (Calvert, Pathak, Ching, Trufil & Fulcher), used biometric and implicit-association testing to show that both giving and receiving good customer service is implicitly experienced as pleasurable. The flip side holds too: an unanswered call with no follow-up isn't a neutral non-event to the person who made it — it's a small, real negative experience, which is consistent with why one missed call can outweigh several good interactions in how a tenant describes a landlord to somebody else.

Speed of response has a large, measurable effect on whether an enquiry converts at all — the clearest evidence for this specific mechanism comes from outside the UK. A widely cited Harvard Business Review study of online sales leads (Oldroyd, McElheran & Elkington, 2011) found that companies contacting a lead quickly rather than slowly saw a large, measurable difference in whether it converted — no directly comparable UK study quantifying that exact effect was found, but it's a US study of B2B sales enquiries, not rental properties, and the Homeflow data above suggests the same slow-response pattern already holds in UK lettings specifically.

None of this is hypothetical when it comes to void periods. UK-wide, void periods and their cost have both been rising: data reported by The Landlord Association put the average void period at 23 days in December 2025, up from 21 days a year earlier, with the average cost of a void rising 13.8% over the same period to £1,077 a month. Every day a property sits empty because a call went unanswered adds to a cost that's already climbing on its own.

Why the number is usually an underestimate

This formula only counts void days and repair cost. It leaves out the softer costs the section above touches on — a prospective tenant who mentions a bad experience to somebody else, or an existing tenant who starts looking elsewhere because they felt unreachable. Those don't show up in a spreadsheet, but they compound the same way.

Reducing the number that goes into this formula

The only variable in this formula that's actually controllable day to day is how many calls go missed in the first place. A dedicated number with automatic SMS replies (on a number that supports SMS, as long as your text allowance isn't exhausted) and call transcripts (see our post on how missed calls drive up void periods) doesn't change the rent or the size of a leak — it reduces how often the "missed" branch of this calculation gets used at all.

See pricing for what's included, or get in touch if you'd rather talk through your own numbers directly.