Set the scale.
Calibrate each page with two points, or let Auto-Scale read the printed scale legend straight off the sheet.
Innovative PDF markup and measurement software for designers, architects, engineers and contractors.
Designed by an Architect, for people who build things.
$149.99 once per platform. No subscription.
Also on the Mac App Store.
PRECISION, BUILT IN
Real plans. Real Caliper.
Mark up. Make the detail clear.
Measure. Keep quantities with the plan.
Compare. See the whole revision.
What Caliper is
Made for plans,
not paperwork.
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.
01 / Count on your drawing
Built for
takeoffs.
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.
Measure what matters.
Linear, poly, area and angle dimensions. Area and perimeter outputs keep quantities together.
Total it. Export it.
Group quantities by identifier in Scheduler, then export a CSV for your estimating workflow.
Calibrate
- Two-point calibration with smart distance parsing
- Direct scale entry (1/4″ = 1'-0″, 1:100, 1″ = 50', etc.)
- Auto-Scale region picker reads printed scale legends via on-device OCR
- Per-page calibration — only affects the page you're working on
Measure
- Linear dimension
- Poly dimension (multi-segment total)
- Area dimension with unit conversion (sq ft, sq m, etc.)
- Area dimension scheduler — tabulate and total your area takeoffs, grouped by identifier, into a single schedule
- Angle measurement (3-click vertex)
- Dimension text override on any annotation
Display formats
- Decimal inches
- Fractional inches
- Decimal feet
- Feet & inches
- Centimeters
- Meters
- Millimeters
Snap & precision
- Object Snap (O) locks drawing and measurement tools to the PDF's own vector geometry — endpoints, intersections, midpoints and edges — so every 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
02 / Make your mark
A complete
markup suite.
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.
Drawing tools
- Line
- Arrow
- Polyline
- Polygon
- Rectangle
- Circle
- Pen (freehand)
- Curve
- Callout
- Highlighter
- Cloud
- Text
- Stamps
Style controls
- Stroke width, color, opacity
- Solid + dashed line types, scalable dash patterns
- Eight line-end decorations: tick, arrow, arrow filled, arrow open, inverse arrow, triangle, diamond, dot
- Fill colors with separate fill opacity
- Per-tool default styles (set once, draw forever)
- Multi-select inspector — change a single property across a mixed selection without overwriting the rest
03 / Review the whole picture
See what changed.
Keep the detail and the bigger picture
in the same workspace.
Layer your revisions.
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.
Look side by side.
Open two documents side-by-side and keep scroll and zoom in lockstep. Cross-reference details and drag pages between tabs without switching windows.
Your working day
A document workflow
that respects your time.
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.
Documents & tabs
- Multi-tab document interface
- Auto-save annotations straight into the PDF — no extra files alongside it
- Reopen any PDF to keep editing your markups — saves preserve /Rotate, content streams, and revisions cleanly
- Reduce File Size — a quality slider re-compresses heavy scans and image-laden PDFs before you share or archive
- New PDF dialog with page-size presets (Letter, Legal, A4, Tabloid, ARCH D, Custom) and landscape toggle
Pages
- Drag-to-reorder pages in the thumbnail sidebar with live spread-apart preview
- Copy & paste pages between documents
- Insert blank pages, duplicate pages, delete pages
- Multi-page selection for batch operations
Editing
- Edit existing PDF text — click text already baked into the document to retype, correct, or remove it
- Square & polygon marquee Delete — vector-preserving inverted clip
- Square & polygon marquee Cut — extracts the region to the clipboard as a vector PDF
- Paste as a vector stamp on any page or document
- Full Undo / Redo across all operations including destructive edits
Navigation
- Single-page and continuous scroll modes
- Synced split view — two documents, two pages, locked scroll & zoom
- Trackpad two-finger pan, mouse scroll-to-zoom, Cmd+scroll universal zoom, middle-click drag-pan
- Zoom slider with editable percentage entry
- Page counter, jump-to-page, keyboard nav
- Custom rotation cursor with zone hysteresis on annotation handles
- Configurable toolbar — show or hide whole tool sections
Your stamp library, your way
- Custom stamp library backed by PDF source files
- Import any single-page PDF up to 2 MB — Caliper renders a thumbnail and adds it to the library
- Stamps remain crisp vector data through every save and re-save
- Rotation-aware rendering for thumbnails, print, and "Save PDF…" export on rotated pages
Why it exists
Made by a licensed architect who got tired of marking up plans with software that was never designed for the job. Caliper does what a working drawing set actually demands: real dimensions, honest area takeoffs, revision comparison, and markup that survives being handed to someone else.
A closer look
Specifications.
Native tools. Local document processing.
A PDF workflow that stays with your files.
Platforms
- macOS 14 Sonoma or later — Mac App Store or direct
- Windows 10 / 11 — Microsoft Store
- Apple Silicon and Intel — universal binary
File formats
- PDF (1.4 through 2.0)
- PNG / JPEG image import as vector stamps
- Vector PDF clipboard interchange (round-trips with Preview, Illustrator, etc.)
Performance
- Large-format support (24×36 and up)
- Vector-preserving operations on save, cut, paste, and delete
- On-device OCR for Auto-Scale (no network)
- Per-page rendering cache for snap geometry
Privacy
- All document processing happens on your computer
- No telemetry, no account, no cloud
- Your drawings never leave the machine
A one-time purchase
Your next project.
No annual subscription.
$149.99Once. Per platform.
Try the full app free for 30 days — then a one-time $149.99 license unlocks output for good: saving, printing, exporting a flattened PDF or image, reducing file size and exporting a Scheduler CSV. Marking up is never gated. No subscription, ever. Also available on the Mac App Store.
Caliper for Mac
macOS 14 Sonoma or later · Apple Silicon + Intel
Caliper for Windows
Windows 10 / 11 · Microsoft Store
One license per platform. The Windows license is a separate purchase from the Mac license. Licenses are sold by Caliper App LLC — not by Apple or Microsoft.