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Operations Management and Strategic Management · Production Planning and Control

Production Control Techniques: Gantt Chart, Kanban and JIT

Updated 10 October 2026 · Fact-checked

Production control techniques keep output on schedule and in line with plans. A Gantt chart shows planned versus actual progress against time. Kanban uses cards to signal that a process needs more parts. Just-in-time makes and buys items only when needed. Line of balance checks whether a batch is on target at a given date.

Understand Production Control Techniques: Gantt Chart, Kanban, JIT

Production control compares what you planned with what is actually happening on the shop floor. If output falls behind, you act. If it runs ahead, you may be building stock you do not need. The tools in this topic make that comparison visible and simple.

A Gantt chart is a bar chart. Time runs across the top. Jobs or machines are listed down the side. Each job has a bar for its planned time. A second bar or a shading shows how much is done. A vertical line marks today. If the progress shading stops before the line, the job is behind. If it goes past the line, the job is ahead.

Kanban is a Japanese word for card or signal. It controls a pull system. A downstream process uses parts and sends a card back to the upstream process. The card authorises the upstream process to make or move only that quantity. Nothing is made without a signal. This limits work in progress, because the number of cards fixes the maximum stock in the loop.

Just-in-time (JIT) is a philosophy of getting the right items, in the right quantity, at the right time, with minimum stock. Kanban is a tool used to run JIT. JIT needs stable schedules, short set-up times, good quality at source, and reliable suppliers. Without these, a stock-out stops the line.

Line of balance (LOB) is used for repetitive or batch production with delivery dates. You draw a chart showing the number of units that should have passed each stage by today. You then compare actual completed quantities with this balance line. Stages below the line are behind schedule and need attention.

Key rules to remember

Number of Kanbans
N = D × L × (1 + S) ÷ C
D = demand per unit time, L = lead time (same time unit as D), S = safety factor as a decimal, C = container size. Round up to a whole number. Use the form given in the question if it differs.
Gantt progress check
Planned progress to date − Actual progress to date = Lag (if positive)
Measure both in the same unit, such as units or percentage of job. Positive means behind schedule, negative means ahead.
Percentage completion on a Gantt chart
Actual output ÷ Planned total output × 100
Use this when the chart shades the bar by output achieved.
Line of balance position
Balance quantity at a stage = cumulative units that must be delivered by (today's date + the stage's lead-time offset before delivery), read from the cumulative delivery schedule
Compare this balance quantity with the actual units completed at that stage. An earlier stage has a longer lead-time offset, so you read the delivery schedule at a later date. A stage with actual units below its balance quantity is behind.

How to solve Production Control Techniques: Gantt Chart, Kanban, JIT questions

Use this method for any question on Gantt, Kanban, JIT or line of balance. It works for both numerical and theory questions.

  1. 1Identify the tool asked for: Gantt, Kanban, JIT, or line of balance. Note whether the question wants a calculation, a chart, or a comparison.
  2. 2List the data given: planned dates, quantities, actual progress, demand, lead time, container size, safety factor.
  3. 3Make sure all data use the same time unit. Convert days to hours or weeks to days where needed.
  4. 4For Gantt or line of balance, compute planned progress to date and actual progress to date for each job or stage. Find the lag or lead.
  5. 5For Kanban, apply N = D × L × (1 + S) ÷ C and round up. Check the answer for sense: more cards mean more stock.
  6. 6State the result in words: which jobs are late, how many cards are needed, or what stock is held.
  7. 7Add the interpretation ICMAI expects: the cause of delay, the action to take, or the benefit and condition of the technique.
  8. 8For comparison questions, use a two-column layout with points such as trigger, stock, suitability and cost.

Quickest way: Fast route for exam time

When to use it: Use this when you have about 10 to 12 minutes for a 14-mark question or about 2 minutes for an MCQ.

  1. For Gantt MCQs, remember: bar is plan, shading is actual, vertical line is today. Shading short of the line means behind.
  2. For Kanban MCQs, link it to pull, cards, limited work in progress, and JIT.
  3. For a card count, multiply demand by lead time, add the safety factor, divide by container size, and round up.
  4. For JIT versus MRP, remember: JIT pulls on actual consumption, MRP pushes using forecast and a plan.
  5. For theory answers, write definition, working, advantages, limitations, in that order, with three or four points each.

Common mistakes in Production Control Techniques: Gantt Chart, Kanban, JIT

  • Reading a Gantt chart bar as actual work done.

    Students forget that the outline bar shows the plan and the shading shows the progress.

    Fix: Always compare the end of the shading with the today line. Say clearly which is plan and which is actual.

  • Calling Kanban and JIT the same thing.

    Both appear together in lean topics, so they blur.

    Fix: Write that JIT is the philosophy and Kanban is a signalling tool used to run a pull system within it.

  • Describing JIT as a push system.

    Students confuse it with MRP, which schedules by forecast and bill of materials.

    Fix: Say JIT is pull: production starts only when a downstream process or customer demand signals a need.

  • Not rounding up the number of Kanbans or mixing time units.

    Demand is in days and lead time is in hours, or the result is a decimal.

    Fix: Convert to one unit first. Always round the final card count up to the next whole number.

  • Listing only advantages of JIT.

    Textbooks stress benefits, so students skip risks.

    Fix: Add the conditions and risks: supplier dependence, a stoppage if one part is late, need for stable demand and high quality.

Worked examples

Example 1

A Pune firm plans to make 400 units of a component over 8 days at an even rate. At the end of day 5, a Gantt chart shows 230 units completed. State whether the job is ahead or behind and by how many units.

Show the solution
  1. Planned rate = 400 ÷ 8 = 50 units per day.
  2. Planned output by end of day 5 = 50 × 5 = 250 units.
  3. Actual output by end of day 5 = 230 units.
  4. Lag = 250 − 230 = 20 units.
  5. Percentage completion = 230 ÷ 400 × 100 = 57.5%. Planned completion = 250 ÷ 400 × 100 = 62.5%.
  6. Interpretation: the shading stops short of the today line. The job is behind and needs corrective action such as overtime or a check on machine availability.

Answer: The job is behind schedule by 20 units (57.5% done against 62.5% planned).

Example 2

A Chennai auto-parts plant uses Kanban. Demand is 480 units per day. Lead time for replenishing a container is 0.5 day. Each container holds 40 units. The safety factor is 10%. Find the number of Kanbans required.

Show the solution
  1. Use N = D × L × (1 + S) ÷ C.
  2. D = 480 units per day, L = 0.5 day, S = 0.10, C = 40 units.
  3. D × L = 480 × 0.5 = 240 units.
  4. With safety: 240 × 1.10 = 264 units.
  5. N = 264 ÷ 40 = 6.6.
  6. Round up to the next whole number: 7 Kanbans.
  7. Check: 7 containers × 40 = 280 units, which covers the 264 needed. 6 would give 240, which is less than 264.

Answer: 7 Kanbans are required.

Exam tips

  • Expect MCQs asking what a Gantt shading, a Kanban card, or a pull system means. Learn the one-line definitions exactly.
  • In a 14-mark theory answer, include working, advantages, limitations and conditions for success. Step marks are given for each.
  • Practise one Kanban card-count problem and always show the formula, the substitution and the rounding.
  • If asked to compare JIT and MRP, use a table-style list in points: trigger, stock levels, forecast reliance, supplier relation.
  • When drawing a Gantt chart, label time on the horizontal axis, jobs on the vertical axis and mark the review date clearly.

Practice questions from Production Planning and Control

Production Control Techniques: Gantt Chart, Kanban, JIT: frequently asked questions

What is a Gantt chart in production control?

It is a bar chart that plots jobs against time. Planned time is shown by bars, and actual progress is shaded or marked on them. It helps you see which jobs are behind or ahead of schedule.

How does just-in-time production work?

Materials and parts arrive and are processed only when they are needed. This keeps stock low. It depends on reliable suppliers, good quality, short set-up times and steady schedules.

What is the difference between JIT and MRP?

MRP is a push system. It plans orders from forecasts, the master schedule and the bill of materials. JIT is a pull system. It starts production only when a downstream need is signalled, and it aims for minimum stock.

How is Kanban related to JIT?

Kanban is a card-based signalling tool. It lets a downstream process request parts from an upstream process. It is one of the ways a JIT pull system is run on the shop floor.