What is First response time?
First response time measures the gap between receipt and the first substantive reply. Two distinctions decide whether the number is worth anything. First, only a reply that moves the case counts: an automatic acknowledgement is a receipt, not a response. Second, what matters is the moment of receipt, not the moment somebody opens the message. Wherever a message sits in the meantime, the clock is unaffected.
Speed-to-lead is the narrower sibling of this metric: it only measures the path to a new prospect in sales. First response time covers everything that comes in - the existing customer with a problem, the job applicant, the authority, the supplier. That is precisely why it is only useful when reported per lane. A business does not have one first response time, it has one per kind of message, and the promises behind them differ.
Take the median, not the mean. A single message left over a weekend drags any average so far up that the number stops being usable, while a median across the whole inbox does the opposite and hides the one case that was left lying. And calculate in business hours, otherwise you are mostly measuring how many public holidays fell into the period.
Why does First response time matter?
The reason the metric is needed at all is volume. On 13 January 2026 Bitkom reported that people using the internet at work receive an average of 53 business emails a day, up from 40 in 2024 and 26 in 2021, with 14 per cent receiving 100 or more. At that volume a stranded enquiry is invisible as long as nobody measures per lane.
First response time in practice
- 01A service business agrees on two promises rather than one average: enquiries at a median below four hours, administrative post within two working days.
- 02The shared mailbox also tracks the first response time of the uncertain lane. If it sits well above the enquiry lane, the third lane has turned into a siding.
- 03A team without a ticketing system measures from the first manually written reply in the mailbox, expressly not from the automatic acknowledgement.
