17 annotation types
Lines, arrows, rectangles, circles, polylines, polygons, freehand pen, curves, callouts, clouds, text, and stamps — every tool with line type, color, opacity, and end-decoration controls.
Made by an architect
Generic PDF readers treat construction drawings like documents. Caliper treats them like drawings: scale-aware measurement, snap-to-geometry precision, vector-clean edits, and a markup suite engineered around the tools you'd reach for on a hard copy — pencils, scales, stamps, and a redline pen.
Lines, arrows, rectangles, circles, polylines, polygons, freehand pen, curves, callouts, clouds, text, and stamps — every tool with line type, color, opacity, and end-decoration controls.
Per-page scale calibration with smart distance parsing — or let Auto-Scale read a printed scale legend ("1/4″ = 1'-0″") with on-device OCR. Linear, polyline, area, and angle dimensions in seven formats, decimal inches through millimeters.
Object Snap (O) locks drawing and measurement tools to the PDF's own vector geometry — endpoints, intersections, midpoints, and edges — so every line and dimension lands exactly on the drawing instead of near it.
Optional grid overlay with customizable spacing, color, and opacity. Grid Snap (G) locks tools to grid intersections for fast, aligned layout work.
Build a custom stamp library — import any single-page PDF as a reusable stamp. Vectors stay vectors through every save cycle.
Open two documents side-by-side, scroll and zoom in lockstep. Compare revisions, cross-reference details, drag pages between tabs — without switching windows.
Marquee any region, then delete it from the PDF — or cut it to the clipboard as a vector PDF and paste it back as a stamp. No rasterization, no blurry zoom.
Lay one drawing over another with adjustable opacity, scale, rotation, and a color tint — in front or behind — to compare revisions, check fit, and see exactly what changed between two sets.
Set the default color, width, opacity, line type, and end decorations for every tool once — then draw all day without touching the inspector. Reset any tool, or all of them, in a click.
Every drawing tool you'd expect from a redline workflow, with the style controls of a vector editor. Tools snap, dimensions update live, and a multi-select inspector only touches the properties you actually change.
Scale calibration is per-page, so a set with mixed scales doesn't fight you. Caliper parses every architect's shorthand — fractions, feet-inches, decimal feet, metric — and converts cleanly between them.
Tabs, sidebars, and auto-save that write your markups straight into the PDF — one file, no loose attachments — and keep every annotation fully re-editable each time you reopen it.
Your stamps, your way — import any single-page PDF and it becomes a reusable stamp. Build a library that's entirely yours.
Try the full app free for 30 days — then a one-time $149.99 license unlocks saving, printing, and editing for good. No subscription, ever. Also available on the Mac App Store.
macOS 14 Sonoma or later · Windows version coming soon · One license per platform