Draw it, size it, export it
Start from a floor plan in the browser: devices, circuits, a panel schedule, a single-line diagram and a calculated bill of materials.
Open demo See pricingThis guide covers what a takeoff produces, how to read quantities without fooling yourself, and where the numbers go wrong.
What a takeoff is — and what it is not
A takeoff answers one question: how much material and how much work is in this drawing? It produces counts, lengths and a bill of materials that an estimator can price.
It is not a design check: a drawing with no circuit for the bathroom heater gets priced as drawn. It is not an estimate, although the two are sold together. And it is not a site visit — drawings lie about voids, existing services and access.
Inputs: what you can take off from
The takeoff is capped by the source file. Vector PDFs are best: lines and blocks carry coordinates, so lengths and counts can be extracted semi-automatically. Scans are worst: everything depends on resolution and on a human deciding what a smudge means.
| Input | Works well for | Breaks on | Practical advice |
|---|---|---|---|
| Vector PDF | Measuring lengths, snapping, repeated blocks | Exploded or rotated blocks, merged layers | Verify scale on two dimensions, not one |
| Scanned PDF or image | Overview, areas, manual markup | Blurred symbols, skew, no object data | Calibrate, zoom in, count in two passes |
| DWG / DXF | Exact geometry, block names, layers | Proxy objects, missing xrefs, wrong units | Check block names against the legend |
| Paper | Nothing automatic | Everything | Site measure, or redraw the plan |
If you cannot state the plan's scale in millimetres per pixel, you are guessing. GorkyCAD Pro sets scale from a known dimension on import and keeps that calibration with the project so a reviewer can check it later.
Counting devices without losing track
Counting feels easy, which is why it gets no method.
- Build the symbol legend first. Decide which symbol is a double socket, which is data, which is a blank plate; map each to your catalogue.
- Count by room, not by drawing. Room counts are self-checking: fifteen sockets in a 4 m² hallway is a warning, not a quantity.
- Mark as you go. Count on a printed copy with a highlighter if the tool cannot colour symbols. Double counting is invisible until procurement.
- Reconcile against the panel schedule. Nine circuits on the schedule against fourteen on the plan means one document is wrong.
Measuring lengths honestly
Horizontal runs are the easy part. The money is in what nobody draws: drops to switches, rises into ceiling voids, slack at boxes, loops at luminaires.
- Calibrate against a printed dimension, then verify against a second one. If the two disagree, the scan is distorted.
- Measure along the containment route, not in a straight line between devices.
- Add vertical drops explicitly — roughly 1.2 m from floor box to switch, and full floor-to-ceiling for ceiling drops. Measure your own project.
- Apply waste per cable size, then round up to purchasable drum lengths.
What a takeoff should output
A takeoff that only produces a total cannot be checked.
| Output | Unit | Derived from | Typical waste | Common error |
|---|---|---|---|---|
| Sockets, switches, luminaires | pcs | Symbol counts | 2–5% | Counting legend symbols as devices |
| Cable by size and cores | m | Routes plus drops | 8–12% | Ignoring verticals and slack |
| Conduit, trunking, tray | m | Containment routes | 5–10% | Straight lines device to device |
| Back boxes, accessories | pcs | Device count | 3–5% | Forgetting boxes for blank plates |
| Board and ways | pcs | Circuit count | — | No spare capacity |
| Labour hours | h | Quantities × labour units | — | Units for the wrong building type |
GorkyCAD Pro builds the table from the drawing model: devices carry catalogue data, routes carry measured lengths, and the bill of materials is generated, not typed. The next step is covered in our electrical estimating software guide.
Worked example: a 68 m² two-bedroom flat
These numbers come from a typical full rewire; they are illustrative, not a benchmark.
- 19 general double sockets, 7 dedicated appliance outlets (cooker, oven, dishwasher, washing machine, fridge, boiler, extractor)
- 15 lighting points, 11 switches, one fourteen-way board with a spare way
| Item | Measured | +10% waste | Ordered |
|---|---|---|---|
| 3 × 2.5 mm² (ring circuits) | 240 m | 264 m | 3 drums = 300 m |
| 3 × 2.5 mm² (dedicated) | 60 m | 66 m | 1 drum = 100 m |
| 3 × 1.5 mm² (lighting) | 110 m | 121 m | 2 drums = 200 m |
| 3 × 6 mm² (cooker) | 18 m | 20 m | 1 coil = 25 m |
| 3 × 10 mm² (sub-main) | 22 m | 24 m | 1 coil = 25 m |
Look at the last column. Measured 240 m plus ten percent is 264 m, but cable is bought in drums, so the order is 300 m — an effective waste of 25%. Across twenty flats that is a purchasing decision, and it is exactly what an estimate built on measured metres hides.
Device count is 19 + 7 + 15 + 11 = 52 points. With 60 back boxes and a 180 m containment allowance, the bill is complete enough to price and small enough to check by hand.
Run this on a real plan. Open the GorkyCAD demo, import a floor plan and count one room — no installation required.
From takeoff to estimate
Quantities become a price through three multipliers: material cost, labour units and indirect costs.
Material cost is easy if your price list is dated. Labour units are where the money hides: an hour per socket is a very different bid from forty minutes, and the difference is usually a judgement about wall type, height and access. Indirect costs — preliminaries, supervision, testing, contingency — do not scale linearly with device count.
Keep takeoff and estimate in separate layers. When a variation arrives you want to re-measure without re-pricing the whole job.
Five errors that survive every software
- Counting from the legend. The legend shows one example of each symbol; the plan shows the devices.
- Trusting an uncalibrated scan. A two percent scale error on a 40 m run is 800 mm per run — material across a building.
- Ignoring containment. Cable is cheap next to tray, trunking and the labour to fit it, yet containment is the most frequently omitted line in a small takeoff.
- Mixing revisions. Quantities from revision B priced against revision A produce an error nobody can trace. Date every takeoff and name the file.
- Rounding twice. Waste on an already rounded quantity, then rounded again to pack size, quietly adds ten percent. Round once.
Checklist before quantities go to the estimator
- [ ] Scale calibrated on two dimensions, recorded
- [ ] Drawing revision and date noted
- [ ] Symbol legend mapped to catalogue items
- [ ] Counts done room by room and marked off
- [ ] Counts reconciled against the panel schedule
- [ ] Vertical drops and slack measured, not assumed
- [ ] Containment and fixings priced as separate lines
- [ ] Waste applied per cable size, rounded to pack sizes
- [ ] Exclusions written down (client-supplied kit, builder's work)
- [ ] A second person has checked the two largest lines
Where takeoff tools stop
Software will not tell you that a circuit is missing or that the drawing contradicts the specification — that is a design and review task, covered by separate automated checks. Those checks flag inconsistencies; they do not certify a design against NEC, IEC or any national code, and they do not replace an engineer's review.
Three further limits matter. There is no offline mode: takeoff happens in a browser, so a site with no connection is out. DWG exchange is practical but not lossless, so complex third-party blocks may need clean-up after import. And the symbol and manufacturer library is smaller than in mature desktop packages, which matters for industrial work.
Ready to run this on your project?
Import a plan, run the calculations and export a checked PDF set. Free demo, no installation, no card.
Open demo See pricingFrequently asked questions
Can takeoff software count symbols automatically?
Partly. On clean vector PDFs and DWGs, repeated blocks can be detected and counted, then confirmed by a human. On scans, detection is unreliable enough that counting with a marker beats correcting a bad automatic pass.
How accurate is a takeoff from a PDF?
Lengths are as accurate as the drawing once the scale is calibrated — typically within a percent or two. Counts depend on the person, not the file. The largest errors come from omissions.
Do I need DWG files to take off a plan?
No. A vector PDF with a printed dimension is enough for most residential and light-commercial work. DWG helps when you need block names or exact geometry, and it is essential when the drawing will be edited rather than only measured.
How much waste should I allow for cable?
Five to fifteen percent depending on route complexity; ten percent is a defensible default for straightforward domestic work. Apply it per cable size and record it in the assumptions.
Can I export the bill of materials?
You should insist on it. XLSX export lets you check the numbers, merge a supplier price list and hand them to a purchaser. If a tool only prints a PDF, you cannot audit it — the documentation shows what GorkyCAD exports.
Does a takeoff include labour?
A takeoff produces quantities; labour appears when quantities meet labour units. Some tools bundle both, which hides the assumptions. Keeping them separate shows whether a price moved because of quantity or rate.
Take off your next plan in the browser. Start the demo, then check pricing and the blog for the rest of the workflow.
Sources
- IEC 60617 — graphical symbols for diagrams: https://std.iec.ch/iec60617
- NFPA 70, National Electrical Code: https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70
- NECA — electrical contracting resources and labour units: https://www.necanet.org/
- Gordian (RSMeans) — construction cost data: https://www.gordian.com/