# WIP Limit Calculator (Little’s Law) - Kanera > Work out the work-in-progress limit that delivers your target cycle time from your weekly throughput, using Little’s Law. Free kanban calculator with an explanation of how to apply it. Canonical page: https://www.kanera.app/tools/wip-limit-calculator Free tool # WIP limit calculator. How much work in progress your flow can carry. Enter how many cards the team finishes in a typical week and how long you want a card to take once started. Little's Law gives the work-in-progress limit that makes both true at the same time. ## Your numbers Cards finished per week Your throughput. Average the last 6 to 8 weeks of completed cards. Target cycle time (working days) How long a card should take from the moment someone starts it to done. Working days per week People pulling work 8 cards in progress Exact value 8. At 8 cards a week and a 5 day target, about 2 cards per person can be in progress at once. ### How to use it Set the total board WIP limit to 8 . If you limit per list instead, split it across the in-progress lists in proportion to how long cards usually sit in each. Leave a little slack (one or two cards) for blocked work, and tighten it once the team is comfortable. Lower the limit and cycle time falls; raise throughput and you can carry more. The formula is WIP = throughput × cycle time , with both in the same time unit. ## Why a WIP limit follows from throughput and cycle time Little's Law says that in any stable process the average number of items in progress equals the rate they finish multiplied by the average time each spends in the system. It does not care whether the items are cards, tickets, or customers in a queue. That makes it a design tool. Your throughput is what the team actually delivers, and it does not change by wishing. The cycle time you want is a decision. Multiply the two and you have the only WIP level at which both can be true. Carry more than that and cycle time stretches, because the extra work waits. ### Getting the inputs - Throughput : count cards moved to Done per week for the last couple of months and average them. Kanera's Work Done view gives this per board or across a workspace. - Target cycle time : start from what customers or stakeholders can live with, not from the current average. Five working days is a common first target for a team-sized card. ### Caveats The law holds for averages over a stable period. A team that is doubling in size or changing how it slices work should re-measure after a few weeks. It also says nothing about which cards to pull first; that is what your board's ordering and priorities are for. ## Flow metric questions What is Little’s Law? For any stable process, average work in progress equals throughput multiplied by average cycle time. It holds regardless of what the work is, as long as the measurements cover the same period and use the same units. The WIP limit and cycle time calculators are rearrangements of that identity. Do I count blocked and waiting cards as work in progress? Yes. Anything that has been started and is not yet done is in progress from the customer’s point of view, and it is the waiting time that inflates cycle time. Counting only cards someone is actively typing on gives a flattering but wrong answer. How many weeks of data do I need? Six to eight weeks is a reasonable minimum for an average. Fewer and a single good or bad week dominates. If the team or the way work is sliced changed recently, start counting from the change. Where do I get throughput from Kanera? The Work Done view lists completed cards by date for a board or a whole workspace. Table view can group by completion week and export the counts to Excel. ## More free tools [When will it be done? Paste your weekly throughput and a backlog size. A Monte Carlo simulation gives you a finish date with 50, 85, and 95 percent confidence. Open tool](https://www.kanera.app/tools/throughput-forecast)[Cycle time calculator How long will a card take from start to finish at your current WIP and throughput, and what has to change to hit a target. Open tool](https://www.kanera.app/tools/cycle-time-calculator)[Throughput calculator Calculate the completion rate needed to sustain your WIP at a target cycle time, using Little’s Law. Open tool](https://www.kanera.app/tools/throughput-calculator) [All free tools](https://www.kanera.app/tools) ## Set the limit, then see it hold across every board. Kanera boards show per-list card counts, overdue and inactive signals, and Work Done history, so you can see whether the limit is respected without a separate spreadsheet. [Start free](https://board.kanera.app/signup)[See board health](https://www.kanera.app/features) No card required, 30-day Pro trial, free plan available after it ## Machine-readable resources - [Kanera AI index](https://www.kanera.app/llms.txt) - [Kanera documentation index](https://www.kanera.app/docs/llms.txt) - [Agent discovery guidance](https://www.kanera.app/agents.md)