Set the finished trim size first. Bleed extends outside it. Safe margins sit inside it. Follow your printer’s specifications.
Your page at print size
- Full canvas, with bleed
- 188 × 263 mm
- Trim size
- 182 × 257 mm
- Safe area
- 162 × 237 mm
- Required pixels, with bleed
- 2221 × 3107 px at 300 dpi
Effective resolution uses the weaker axis. Different aspect ratios require cropping, stretching or borders. Changing a DPI label does not add image detail.
Trim, bleed, safe area and pixels
Trim is the final page after cutting. Bleed adds artwork outside the trim. A safe margin keeps important text and faces away from the cut. Neither bleed nor safe margins have one universal value. Ask your printer.
The B5 preset uses JIS B5, 182 × 257 mm. A4 and A5 use ISO A sizes. The 220 × 310 mm manuscript trim is a workflow preset, not a standard book size.
The arithmetic
Full width = trim width + twice the bleed. Safe width = trim width − twice the safe margin. Required pixels = millimetres ÷ 25.4 × dpi, rounded up on each axis.
Example: 182 × 257 mm, with 3 mm bleed, gives 188 × 263 mm. At 300 dpi, that needs 2221 × 3107 pixels.
For an existing image, effective dpi = pixel count ÷ physical size in inches. The weaker axis determines the result. A 1200 × 1800 image printed at 4 × 6 inches has 300 dpi. Setting a higher DPI label does not create missing detail.
Try the panel layout maker for its available paper presets. Custom calculator dimensions do not transfer automatically. Read the manga page size guide for paper and manuscript distinctions.
Common questions
What is effective DPI?
It is the pixel count divided by print size in inches. This checker reports the lower of the horizontal and vertical values.
Does changing DPI improve an image?
Changing a DPI label alone adds no detail. More pixels require a different source or resampling, which this checker does not perform.
How much bleed should I use?
Follow your printer’s specification. The default 3 mm is an editable planning value. It is not a universal requirement.
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