How to use it
- Measure your cup across (or around) at the top and bottom edges of the area you want to print, and the height between them.
- Add your design: any rectangular image, such as a design made for a straight tumbler. Choose how it fills the wrap.
- Check the preview. The flat wrap shows the cut line; the cup view shows how the design will look once it is wrapped.
- Tick Mirror the print for sublimation or iron-on transfers, then download the PDF or PNG.
- Print the blank test-fit PDF on plain paper first and wrap it around the cup. If it fits, print your design at 100% / Actual size.
How to measure your cup
Cups sold as the same size (a "20 oz tapered tumbler", say) often differ by a few millimetres between brands, so measure the one you are decorating. You need three numbers:
- Top and bottom size, taken where the top and bottom edges of the wrap will sit, below any rim or lid and above any base. Measure straight across (the diameter) with a ruler, or wrap a tape measure or a strip of paper around the cup (the circumference). The circumference is usually easier to measure accurately.
- Printable height: either straight up, with a ruler held upright beside the cup, or along the sloping side, with a tape laid on it. Choose which one you measured; on a typical tumbler the two differ by only a few hundredths of an inch, but on a strongly tapered cup the difference matters.
Straight and tapered tumblers
A straight (cylindrical) tumbler unrolls into a plain rectangle: its width is the circumference and its height is the printable height. The generator handles that case too; enter the same size for the top and bottom.
A tapered tumbler is part of a cone, and a cone unrolls into a curved band: an arch whose top edge is longer than its bottom edge. A rectangular design printed straight onto paper cannot wrap it neatly: it leaves a wedge-shaped gap at the seam or overlaps at the bottom. The design has to be bent to follow the curve, which is what this tool does.
How the curved template is calculated
With top radius R and bottom radius r (half the diameters; for a cup wider at the bottom the roles swap) and vertical height H, the wrap is the region between two arcs that share a centre:
Worked example: a cup 3.5 in across the top, 2.5 in across the bottom and 6.5 in high has a side length of 6.519 in. The inner arc has a radius of 16.30 in and the outer arc 22.82 in, and the wrap spans an angle of 27.61°. The outer arc is then exactly as long as the top circumference (11.00 in) and the inner arc as long as the bottom circumference (7.85 in).
The generator's maths is checked by automated tests against an independent reference calculation, and by wrapping the pattern onto a 3D model of the cup to confirm that no part of it stretches. A straight cup is handled exactly as a rectangle, and very slight tapers are drawn exactly without numerical problems.
How your design is bent to fit
Each point of your design keeps its place around the cup and its distance down the side. The left and right edges of the design meet at the seam, horizontal lines follow the rim, and vertical lines run straight up the side. Because a tapered cup is wider at one end, the design is slightly wider there too: proportions are exact at mid-height, and the tool tells you how much wider and narrower the ends are. No rectangular design can wrap a tapered cup exactly once without that change.
- Fill keeps your design's proportions and crops whatever does not fit. Use the sliders to choose which part shows.
- Whole image keeps the proportions and shows all of it, leaving space (transparent, or a colour you choose).
- Stretch fills the wrap exactly, distorting the design if its shape does not match; the tool tells you by how much.
For best results, make your design the shape of the unrolled wrap (listed under All dimensions) and at least 300 dpi at the wide end. Transparent PNGs stay transparent. If you add an overlap, it repeats the start of your design so the join is seamless.
Why printed scale matters
A wrap that prints even 2% small leaves a gap of about 5 mm (0.2 in) at the seam of a 20 oz tumbler. Always print at 100% / Actual sizeand turn off "Fit to page", which most browsers and PDF viewers switch on by default. Every PDF includes a 2 in or 50 mm scale bar: measure it with a ruler before printing on sublimation paper. The PNG records its resolution, so programs that read it (such as Photoshop, GIMP, Affinity and Inkscape) place it at the right size. Some design apps ignore that setting; in those, set the image size by hand to the size the tool shows when you download.
Mirroring for sublimation
Sublimation and iron-on transfer prints face the cup, so they must be printed back to front. Tick Mirror the print and the PDF, PNG and SVG are all flipped, including the overlap, which moves to the other end. Do not also mirror in your printer settings. Stickers, printable vinyl and paper sleeves are not mirrored.
Limitations
- The cup's side must be straight between the top and bottom measurements (a cone or a cylinder). Cups with curved, bulging or stepped sides need a wrap for each straight section, and handles or lids are not modelled.
- The wrap is printed on one sheet, because transfers cannot be tiled. If it is larger than your printer's paper, use the PNG or SVG with a larger-format printer.
- The template is only as accurate as your measurements. Test it on plain paper first. Paper thickness and how tightly you wrap also make a small difference.
- Images are handled in your browser's memory: images up to 64 megapixels are accepted and those over about 16.7 megapixels are reduced. Colours are converted to standard sRGB and colour profiles are not kept.
- The PNG stores its resolution in whole pixels per metre, so 300 dpi is recorded as 299.9994 dpi (a 0.0002% difference). Printers themselves can be off by a fraction of a percent; the scale bar tells you how accurate yours is.
Frequently asked questions
- Is my design uploaded anywhere?
- No. The image is read and processed by this page on your own device. Nothing is sent to a server and there is no account.
- What resolution should my design be?
- 300 dpi at the final size is the usual target for sublimation and printing. The tool warns you if your image will print at under 150 dpi at the wide end of the cup.
- Why is my design wider at the top?
- Because the top of a tapered cup is wider. The design has to go all the way round at every height, so it is stretched slightly where the cup is wide and squeezed where it is narrow. Proportions are exact at mid-height.
- What paper size do I need?
- The tool picks the smallest listed sheet that holds the wrap in one piece. The example 20 oz wrap needs US Legal (8.5 × 14 in) or A3; larger cups may need Tabloid (11 × 17 in).
- Can I use it with Cricut or Silhouette?
- Yes. The SVG cut file has real units and lines up with the PNG when both are placed at the same position, for print-then-cut. Set the image size by hand if your software ignores the PNG's resolution.
- Does it work for cups that are wider at the bottom?
- Yes. Enter the top and bottom as measured; the wrap curves the other way and your design stays upright.
- Can I make other cones, such as lampshades or party hats?
- Any shape with straight sloping sides works if the wrap fits on one sheet. For cones to a point, sheet metal and multi-piece patterns, use the cone flat pattern calculator.