Why the height field is the one that matters
Four cords is 512 cubic feet of stacked wood. That number never changes. What changes is the shape you pour it into, and the arithmetic is one division: face length = stacked volume ÷ (stack height × stack depth).
At four rows of 16-inch wood with a small gap, the stack is about 5.8 feet deep. Stack it 4.5 feet high and you need roughly 19.5 feet of face. Stack the same wood 3 feet high and the face grows to about 29 feet — half again as long, for exactly the same firewood. Stack it 8 feet high and it fits in 11 feet, except that nobody stacks 8 feet high twice.
So the question a woodshed answers is not “how much do I burn”. It is “how high will I stack, in February, in the dark, with wet gloves on”. Answer that honestly and the building draws itself.
Rows deep is the second decision, and it is a drying decision
Rows deep trades floor shape against airflow. One row of 16-inch wood is 1.33 feet deep and dries from both faces; four rows is 5.8 feet deep and the middle two dry from neither. If the wood arrives green and has to season in the shed, depth is working against you. If it arrives seasoned and the shed is only keeping it dry, depth costs nothing and saves wall.
The gap field exists for the same reason. Two inches between rows is not much, but it is the difference between air crossing the stack and air going round it. The firewood BTU and seasoning calculator shows what unseasoned wood actually costs you at the stove, which is a bigger number than most people expect and is the argument for the shallower shed.
The overhang is trigonometry, not a rule of thumb
Rain that falls straight down needs no overhang at all. Rain at 30 degrees off vertical, arriving at an eave 7 feet above the bottom of the stack, lands 7 × tan(30) = 4.0 feet inside the drip line. That is the number in the overhang row, and it is why a shallow porch roof over a tall stack does very little on the days it is needed.
You have two ways to spend that 4 feet: roof, or set-back. A foot of extra overhang and a foot of extra front clearance keep the same rain off the same wood, and the clearance is free. Most well-built woodsheds do some of each, and the front row ends up a foot or so inside the posts.
What the weight tells you
Four cords of dense hardwood at 32 pounds per cubic foot of solid wood is around 13,000 pounds — six and a half tons sitting on a rectangle the size of a small bedroom. Spread flat that is a modest load, but it is not spread flat: it stands in lines under each row, and those lines want continuous bearing rather than a few blocks. What that means for the base is a question for the shed foundation comparison calculator, which puts skids, blocks, gravel and a slab side by side.
If what you are actually trying to work out is how much wood you have rather than where to put it, run the stack you already own through the firewood cord calculator first — it converts a measured pile into cords and face cords, which is the input this page wants. For how much a winter takes, the heating fuel reserve calculator works from consumption instead.
What this page does not do
No loads, no spans, no separation distances, no code. It converts cords into a rectangle and tells you what the rain geometry implies. Roof framing for snow, post sizing, and how close the shed may sit to anything else are all decided elsewhere — by an engineer, by the building department, and in fire country by whoever administers defensible space where you live.
Questions people ask
How high do people really stack firewood?
Four to five feet is where most single-row hand-stacked wood ends up, because that is the height you can place a split without lifting it above your shoulder and without the stack going unstable. Cribbed ends can go higher; free-standing rows of round-faced splits generally should not. The reason it matters here is that the footprint scales inversely with it: dropping from 5 feet to 4 makes the shed 25 per cent longer for the same wood. Decide the height first, then read the length off, rather than picking a shed size and hoping.
Is a face cord the same as a cord?
No, and this is where firewood buyers lose money. A full cord is 128 cubic feet stacked: 4 feet high, 4 feet deep, 8 feet long. A face cord or rick is 4 feet by 8 feet by whatever the pieces are cut to, so 16-inch wood makes a face cord one third of a full cord, and 12-inch wood makes it a quarter. Sellers quote whichever unit sounds better. Convert to full cords before entering anything here, and the firewood cord calculator will do it from a measured stack.
Should the woodshed have walls?
That is a drying question rather than a size question, so this page does not decide it. Wood dries by losing water to moving air, and a shed with three closed walls and a closed front is a box that holds humid air against the stack. The common arrangement is a roof, a back wall, and open or slatted sides, oriented so the prevailing wind crosses the rows rather than hitting the gable end. The trade is that an open front lets driven rain in, which is what the overhang and set-back rows on this page are about.
Does the wood need to be off the ground?
Yes, in the sense that the bottom row will rot and wick moisture upward if it sits on soil, and that is a well-known way to lose the first course. Pallets, rails, gravel with sleepers and a slab are all used. What this page cares about is only that the stack height is measured from whatever the wood sits on, not from the dirt, because the rain geometry starts there too. What the base should be is covered properly by the shed foundation comparison calculator.
How much wood does a winter take?
That depends on the house, the climate, the appliance and how the appliance is run, and it is a different calculation from this one. Two households in the same town with the same square footage routinely differ by a factor of two. The honest way to find your number is to measure what you actually burned last year rather than estimate it, and if you have no history, the heating fuel reserve calculator works from heating load instead. Size the shed for the number you get plus whatever overlap you want between seasons, because a shed that holds exactly one winter never holds a dry winter.