Line Design Math

How to Calculate Takt Time, Cycle Time, Conveyor Speed, and Line Balance

The core production-line math worked end to end: takt time, cycle time, conveyor speed, dwell time, throughput, and line balance, with real part counts and the source of every input.

Start with takt time, the drumbeat every station must match. Takt equals available production time divided by customer demand for the same window. If a shift runs 8.0 hours with two 15 minute breaks, available time is 8.0 x 60 minus 30 = 450 minutes, or 27,000 seconds. Against a demand of 900 units the takt is 27,000 / 900 = 30.0 seconds per unit. Available time comes from the shift calendar minus planned stops, and demand comes from the daily order or leveled schedule, not from what the line can physically produce. The Takt Time calculator holds this basis so every station is sized to 30 seconds, not to its own comfortable pace.

Cycle time is what the line actually delivers, and it must sit at or below takt. Effective cycle time equals net operating time divided by units completed in that time. If a station produced 480 good units in 4.0 hours of net run, cycle time is 14,400 / 480 = 30.0 seconds per unit. The controlling station, the slowest one, sets the line cycle time and therefore the true output rate. Pull operating time from the machine log after removing downtime, and pull unit counts from the station's good-part counter. The Cycle Time calculator returns per-station values so you can line them up against the 30.0 second takt and spot the station that is over.

Conveyor speed follows directly from spacing and required rate. Belt speed equals part pitch times parts per minute, where pitch is the center to center spacing of parts on the belt. To move 120 parts per minute at a 0.25 meter pitch, speed is 0.25 x 120 = 30 meters per minute, or 0.50 m/s. Reverse it to check capacity: a belt at 45 m/min carrying parts on a 0.30 m pitch passes 45 / 0.30 = 150 parts per minute. Pitch comes from fixture or flight spacing, and target rate comes from takt inverted, 60 / 30.0 = 2.0 parts per second, or 120 per minute. The Conveyor Speed calculator ties pitch, rate, and belt length together so you do not starve a downstream station.

Dwell time is how long a part sits in a zone, and it governs process windows like curing, cooling, or vision inspection. Dwell equals zone length divided by conveyor speed. A 6.0 meter oven zone at 30 m/min gives 6.0 / 30 = 0.20 minutes, or 12 seconds of dwell. If the cure needs 45 seconds, the zone is short: required length is 45 / 60 x 30 = 22.5 meters, or the belt must slow to 6.0 / (45/60) = 8.0 m/min. Zone length is a fixed layout dimension and speed comes from the drive setpoint. The Dwell Time calculator lets you solve for length or speed so the process window is met without stalling the line rate.

Throughput ties the whole line to a time horizon. Throughput equals good units divided by total time, or equivalently the line runs at 3,600 divided by the bottleneck cycle time in seconds per hour. A line with a 30.0 second controlling cycle yields 3,600 / 30.0 = 120 units per hour at full speed, then scaled by uptime. Over a 7.5 hour net run that is 120 x 7.5 = 900 units, matching demand exactly. Feed the bottleneck cycle from Cycle Time and the run window from the schedule. The Throughput calculator reconciles the hourly rate against the shift total so a plausible per-hour number does not hide a shortfall across the day.

Line balance decides how work splits across stations so none exceeds takt. Balance efficiency equals total work content divided by the number of stations times the takt, times 100. With 210 seconds of total assembly content and a 30.0 second takt, the theoretical minimum is 210 / 30.0 = 7.0 stations. Run it across 8 real stations and efficiency is 210 / (8 x 30.0) x 100 = 87.5%, meaning 12.5% of paid station time is idle balance loss. Work content comes from timed element studies, and takt comes from the calculation above. The Line Balance calculator assigns elements to stations under the takt ceiling and reports the idle time per station.

Chain the numbers to size a real line. Takt of 30.0 seconds sets the rate; a bottleneck cycle at or under 30.0 seconds keeps the line feeding; conveyor speed of 30 m/min at 0.25 m pitch delivers 120 parts per minute; a 6.0 m cure zone forces either 22.5 m of length or an 8.0 m/min crawl to hit a 45 second dwell. Machine Utilization then checks whether stations are actually running: a station busy 6.8 of 8.0 hours is 6.8 / 8.0 = 85% utilized. Bottleneck Capacity confirms the controlling station's ceiling so you invest in the right place. Every calculator shares the same shift window and demand basis.

Watch units and denominators, because that is where line math breaks. Seconds, minutes, and units per hour differ by factors of 60, so a 30.0 second takt is 2.0 per minute and 120 per hour; mixing them silently multiplies or divides your rate by 60. Conveyor speed in m/min versus m/s differs by 60 as well, and pitch must be in the same length unit as belt length. Takt uses available time in the denominator, not gross clock time, so forgetting the 30 minutes of breaks understates takt and oversizes the line. Get the basis and the units right, and the rest is arithmetic.

Published 2026-07-01.