Linen wears out by the wash
The mistake is depreciating linen over years. A towel has no idea what year it is; it knows how many times it has been through a machine. Two identical towels bought on the same day, one in a rotation that sees the wash twice a week and one that sees it five times, are finished eighteen months apart. So the only stable life figure is in cycles, and the only way to turn it into a purchase schedule is to know how often each piece is washed.
That second number is easier than it sounds. Total washes of one item in a week, divided by the pieces of that item you own, is the wash frequency. Both halves come off records you already keep.
The number nobody costs
Water gets costed per pound. Gas gets costed per pound. Labour gets costed per pound. Linen arrives as an invoice for a pallet of towels and goes into a different mental box entirely, and then people wonder why the cost of doing a pound of laundry never quite adds up. Divide the delivered price by the cycles the piece survives and you have the linen cost of one wash; divide again by the piece weight and it sits on the same basis as everything else on the bill. On many goods it is larger than the water.
The page also prints the same figure with write-offs folded in, which lowers the effective life. A piece that was good for well over a hundred washes but walked out of the building after sixty cost you the same as one that wore out at sixty.
Price per piece is the wrong comparison
The optional block at the bottom exists because purchasing decisions get made on the wrong number constantly. A heavier towel at a third more money that lasts half again as long is cheaper per wash, and the invoice will never tell you that. The page prints both the annual difference and the break-even price — what the longer-lasting grade would have to cost for the two to be level — which is a considerably better thing to take into a supplier conversation than a preference.
What it cannot tell you is whether the claimed life survives contact with your chemistry, your extract and your handling. Nobody can. Mark a batch, log the washes, and you will have a figure that is yours.
What this is not
It is not a par level calculator. How many pieces have to exist so that there is always clean stock on the shelf while a batch is in the wash and another is in the rooms is a different question with a different structure, and mixing the two is how operations end up buying a year of replacement stock and still running short on a Tuesday. This page answers only how fast the stock you have is being consumed and what that consumption costs.
Questions people ask
How many wash cycles does a towel last?
Nobody can tell you for your goods. It depends on the construction, the chemistry, the extract, the dry temperature and how the pieces are handled between washes, and the honest range across real operations is wide enough to be useless as a default. Mark a batch, log the washes and count how many it takes before you are pulling them for thinning or holes. That is the number the whole page hangs on and it is worth an afternoon to get.
How do I work out the linen cost per pound of laundry?
Delivered price of one piece, divided by the cycles it survives, divided by the piece weight. That puts linen on the same basis as water, gas and labour, which is the only way the true cost of a pound of laundry adds up. The page prints it, and also prints a version with write-offs folded in, since a piece that walked out after sixty washes cost the same as one that wore out then.
Is a more expensive towel cheaper in the long run?
Only if the extra life outruns the extra price, and the page computes that rather than assuming it. Enter both grades and it compares them on cost per wash and prints the price at which the two would be level. A third more money for half again the life is cheaper; a third more money for a fifth more life is not. The claimed life still has to survive your own chemistry before any of it holds.
What replacement percentage a year should I budget?
It falls out of the arithmetic rather than being a rule. Stock divided by the life in years, plus whatever you lose to theft, staining and damage. The page prints it as pieces and as a percentage of the stock. Copying a percentage from another operation imports their wash frequency and their linen life, which are the two things least likely to match yours.
Does this tell me how much linen to own?
No, and it deliberately does not try. Sizing the stock so there is always clean linen available while a batch is in the wash is a different problem with a different structure. This page answers how fast the stock you have is being used up and what that costs, which is a running-cost question rather than an inventory one.