A ream of paper is a standard unit of measurement used to count, package, and sell sheets of paper. One ream consists of 500 sheets of the same size, though that number has shifted over centuries. The term "ream" comes from the Arabic word rizmah, meaning a bundle, and it passed into English through French trade routes during the medieval paper trade.
Whether you're ordering copy paper for offices, ruled writing paper for stationery, or specialist papers for a press run, the ream is the standard unit of paper quantity on every label and purchase order. This guide covers what a ream of paper means, how ream definitions vary by paper type and quality, and how to convert a job's sheet count into reams so you don't over-buy.
Ream of Paper: The Standard Definition
A standard ream is defined as 500 sheets of paper of the same size and quality. That definition applies to most bond, text, and copy paper sold in offices today, including letter (8.5 x 11 in) and A4 sheets. Each ream is typically wrapped in moisture-resistant paper or plastic film to protect sheets from humidity and handling damage.
The 500 sheet ream is sometimes called a "long ream," meaning 500 sheets of paper as the standard unit, to distinguish it from older counts. The term is specifically a paper quantity measurement, not tied to the physical dimensions of the package. A ream of paper does not mean a box; it means the number of sheets inside the wrap. Reams are loaded directly into printers and copy machines for document production, and in schools, reams are used for assignments and handouts.
Reams are typically sold in cases. There are typically 10 reams in a case of paper, or about 5,000 sheets of paper. Schools, offices, and organizations that run through paper save by buying cases, while smaller offices may order two reams at a time.
Cover and Index Paper Ream Counts
Not every ream holds 500 sheets. Reams of cover paper usually contain 250 sheets because the heavier caliper and basis weight make a 500 sheet ream impractical to handle. Cover stock, like 80 lb cardstock or 100 lb cardstock, is thicker per sheet, so halving the ream count keeps the package at a manageable size and shipping weight.
Index paper follows a similar pattern. Reams of index paper typically hold 250 sheets, reflecting the heavier caliper as opposed to standard text weight. Specialty paper packages may contain a different number of sheets but are still called reams, so check the sheet count on the label rather than assuming 500.
Reams of poster-size paper typically contain 516 sheets, a holdover from the printer's ream tradition. And carbonless paper is typically sold in sets, because multi-part forms require matched collating sequences. A 2-part carbonless set like 8.5 x 11.5 perf carbonless, 2-part reverse ships as 10 reams to keep the CB and CF sheets paired correctly through the run.
Short Ream, Long Ream, and Mill Ream
The ream hasn't always meant 500 sheets. Historically, a ream was 480 sheets, or 20 quires at 24 sheets per quire. (In some trades, quires were also called quills.) That old value is called a short ream (or a stationer's ream in the UK), the standard for centuries in European papermaking.
A printer's ream, used in commercial printing, typically consisted of 516 sheets. The extra sheets (called "overs") covered spoilage during makeready and registration adjustments. The mill ream was another variation defined by the paper mill, and its count depended on the type of paper and the region. A mill ream of handmade paper, blotting paper, or tissue paper sometimes held a different number of sheets than a mill ream of writing paper or machine-made bond.
The long ream of 500 sheets has been gradually replacing the short ream, the stationer's ream, and the mill ream since the 20th century. Most organizations now use 500 sheets of paper as the standard definition, though certain types of specialist papers follow older conventions depending on the manufacturer and region. The term ream on a modern label means 500 sheets of the same quality unless stated otherwise.
Quires, Bundles, and Bales
Paper quantity doesn't stop at the ream. The ream sits inside a larger system of measurement with a long history in hand papermaking. A quire (also called a quill in older English usage) is the smallest named unit: traditionally 24 sheets (or 25 in a modern quire). Twenty quires made one ream, which is how 20 quires of 24 gave the 480 sheet short ream, and 20 quires of 25 gave the 500 sheet long ream.
Above the ream, paper is counted in bundles and bales. A bundle consists of two reams, so five bundles equal 10 reams, or one full case. A bale is a large amount of paper used in warehouse and mill transactions. For example, the number of reams in a bale varies depending on paper size, caliper, and weight, but a bale typically holds five bundles (10 reams) for standard bond. For heavier stock, bales may hold fewer reams.
You'll still see quires, quills, bundles, and bales in trade catalogs around the world, particularly the Netherlands and UK. For most purchasing in offices and print shops, the ream and the case are the quantities that matter.
Ream Count, Basis Weight, and Shipping Weight
A ream of paper is not a measure of weight, but ream count, basis weight, and shipping weight are connected. Basis weight refers to the weight of 500 sheets (one ream) at its basis size, which varies by grade. For bond and writing paper, that basis size is 17 x 22 inches. For cover stock, it's 20 x 26 inches.
So "20 lb bond" means 500 sheets at 17 x 22 inches weigh 20 pounds. Cut to letter (8.5 x 11 in), each ream is lighter, but the paper is still called 20 lb bond. A single ream of 20 lb letter paper weighs about 5 pounds, not 20. The measurement refers to the uncut ream at basis dimensions.
For ordering, check the finished ream weight for your cut size. A case of 10 reams of 20 lb letter bond weighs roughly 50 pounds. Heavier stocks like 100 lb paper stock weigh considerably more per ream. Factor shipping weight into your order when buying multiple cases, especially with premium grades and larger dimensions.
Converting Job Quantities Into Paper Orders
Print buyers who know ream counts can save money by ordering the right quantity depending on the job. Start with the total finished sheets you need, then add spoilage. Offset jobs call for 5 to 10 percent overs, while digital runs tighter. Divide the total by 500 for text and bond, or by 250 for cover and index paper, and round up.
Here's an example: a 2,000 piece job on 80 lb cover with 10 percent overs needs 2,200 sheets. That's 8.8 reams of 250 sheets, so you'd order 9 reams. Another example on 20 lb bond: 2,200 sheets is 4.4 reams of 500 sheets, so 5 reams covers it.
Carbonless paper and pre-perforated carbonless are sold in matched sets, so you'll order by the set count rather than individual reams. Products like 9 x 11 perf carbonless, 2-part reverse come as 10 reams per carton. Waterproof and specialty media, like 13 x 19 tearfree waterproof paper, are sold by sheet count (50 sheets per pack) rather than by the ream, so confirm the quantity per unit before ordering.
Frequently Asked Questions
What Does 1 Ream of Paper Mean?
One ream of paper is a standardized quantity defined as 500 sheets of the same size, type, and quality. The term ream is primarily a quantity measurement, not a description of the physical package. It applies across paper grades, from accent opaque laser paper to omnilux gloss text paper, though specialty stocks may have different counts per ream.
Is a Ream of Paper 20 Lbs?
Not exactly. "20 lb" on a ream of paper refers to the basis weight, not the shipping weight. A ream of 20 lb bond weighs 20 pounds only at its full basis size (17 x 22 inches). Cut to letter size, one ream weighs about 5 pounds. The basis weight number tells you the paper's thickness and feel, while the actual package weight depends on the cut size and sheet count.
Is a Ream of Paper a Box?
No. A ream of paper is a quantity of sheets, not a container. One ream is 500 sheets wrapped in a protective sleeve. A box (or case) of paper typically contains 10 reams, which adds up to 5,000 sheets. When you buy a "box" of paper at an office supply store, you're getting a case of multiple reams, not a single ream.
How Many Sheets of A4 Paper Are in a Ream?
A ream of A4 paper contains 500 sheets, the same count as letter. A4 measures 210 x 297 mm (about 8.27 x 11.69 inches), and the standard ream quantity applies regardless of paper dimensions. The ream count stays consistent across sizes; only weight and package dimensions change.
Stock Up on Paper and Printing Supplies
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By the Printing Supplies Direct Team.