Speed to lead: four small calculators

All starting numbers are invented for illustration, not market data. Write numbers like 1000, 1,000 or 2,5. A value such as 1.000 is ambiguous and is rejected, so write 1 or 1000.

A. Median and 90th percentile from response times

Minutes from enquiry to first human contact, one per lead. Separate with spaces, semicolons or new lines. Write "never" for a lead nobody contacted.

B. Median and 90th percentile from time buckets, with a contact curve

Contact chance for a very fast first call (%) Contact chance floor for a very late call (%) Minutes for the gap above the floor to halve

Bucket	Leads	Contact chance at midpoint (%)	Expected leads reached

C. Wall-clock delay for out-of-hours enquiries

Days open per week, from Monday (1 to 7) Opening hour (0 to 24) Closing hour (0 to 24)

D. Queue at a peak hour (Erlang C)

New leads per hour Minutes of rep time per lead Reps free to answer leads

Section A uses the 90th percentile method of the Excel function PERCENTILE.INC. A never-contacted lead counts as slower than every time. If the percentile falls on one, the result says "not reached". Section B places each bucket at its midpoint, spreads leads evenly inside a bucket to estimate percentiles, and treats the first 7 days as the last bucket. The contact curve is chance = floor + (fast chance minus floor) x 0.5 to the power (minutes / half-gap). It is an invented shape, not a fitted one. Its scenario moves every lead slower than 60 minutes into the 15 to 30 minute bucket and assumes the delay caused the lower contact chance. Section C assumes enquiries arrive evenly across the week and the first call happens at the next opening. Section D assumes random arrivals, one shared queue, first come first served and exponential call lengths. The tool is arithmetic on your inputs, not a forecast.