The project legend governs. Abbreviations vary by firm and discipline. Always check the abbreviation list on the general sheets; when a project uses a term differently from common usage, the project's definition wins. Many firms base their lists on the U.S. National CAD Standard.
Units of measure
| Abbrev. | Meaning | Typical use |
|---|---|---|
| SF | Square feet | Flooring, drywall, paint, roofing |
| SY | Square yards (9 SF) | Carpet, paving, some earthwork |
| LF | Linear feet | Base, pipe, conduit, curb, trim |
| CY | Cubic yards (27 CF) | Concrete, excavation, fill |
| CF | Cubic feet | Small volumes, grout |
| EA | Each | Fixtures, devices, doors |
| LS | Lump sum | Items priced as one total |
| SQ | Roofing square (100 SF) | Roofing, siding |
| BF / MBF | Board foot (144 cubic inches) / thousand board feet | Lumber |
| SFCA | Square feet of contact area | Concrete formwork |
| TN / T | Short ton (2,000 lb) | Steel, asphalt, aggregate |
| CWT | Hundredweight (100 lb in U.S. usage) | Rebar and steel pricing |
| GAL | Gallon | Paint, coatings |
| HR / MH / LH | Hour / man-hour / labor-hour | Labor |
| VF | Vertical feet | Risers, manhole depth |
Ambiguous abbreviations to watch
- MH: man-hour in an estimate; manhole on a civil sheet.
- C: conduit, cold, ceiling or centerline, depending on the set.
- EQ: equal (dimensions) or equipment.
- FD: floor drain on plumbing sheets; fire damper on mechanical sheets.
- CB: catch basin (civil) or circuit breaker (electrical).
- T: ton, thermostat, or tread.
- PF: plumbing fixture, per foot, or power factor.
When the meaning is unclear, send an RFI rather than guessing.
General drawing abbreviations
| Abbrev. | Meaning |
|---|---|
| TYP / SIM | Typical / similar |
| NTS | Not to scale |
| AFF / FFE | Above finished floor / finished floor elevation |
| TOS / TOC / TOW / BOF | Top of steel / top of concrete / top of wall / bottom of footing |
| O.C. / CLR / EQ | On center / clear / equal |
| FV / VIF | Field verify / verify in field |
| NIC / BO | Not in contract / by others |
| GWB / ACT / VCT / LVT | Gypsum wallboard / acoustical ceiling tile / vinyl composition tile / luxury vinyl tile |
| IE / INV | Invert elevation |
Plumbing, mechanical and electrical
| Abbrev. | Meaning |
|---|---|
| WC / LAV / UR / MS | Water closet / lavatory / urinal / mop sink |
| FD / HB / EWC | Floor drain / hose bibb / electric water cooler |
| CW / HW / HWR / DWV | Cold water / hot water / hot water return / drain, waste and vent |
| RTU / AHU / VAV / ERV | Rooftop unit / air handling unit / variable air volume box / energy recovery ventilator |
| FD / SD / FSD | Fire damper / smoke damper / combination fire-smoke damper |
| GFCI / AFCI | Ground-fault / arc-fault circuit interrupter |
| MCC / VFD / ATS | Motor control center / variable frequency drive / automatic transfer switch |
| EM / WP / WR | Emergency / weatherproof / weather-resistant |
Contract and estimating terms
| Abbrev. | Meaning |
|---|---|
| RFI / ASI / CCD | Request for information / architect's supplemental instructions / construction change directive |
| PCO / COR / CO | Potential change order / change order request / change order |
| OFCI / OFOI / CFCI | Owner furnished contractor installed / owner furnished owner installed / contractor furnished contractor installed |
| GMP / T&M / OH&P | Guaranteed maximum price / time and material / overhead and profit |
| SOV / NTP / LDs | Schedule of values / notice to proceed / liquidated damages |
| AHJ / EOR | Authority having jurisdiction / engineer of record |
| VE / ALT | Value engineering / alternate |
Conversions
1 SY = 9 SF 1 CY = 27 CF 1 SQ = 100 SF
CY = SF x thickness (in.) / 12 / 27
1 BF = 1 in. x 12 in. x 12 in. BF = thickness (in.) x width (in.) x length (ft) / 12
1 m² = 10.764 SF 1 m = 3.281 ft 1 metric ton = 2,204.6 lb
Illustrative conversions
carpet: 1,800 SF / 9 = 200 SY
slab: 2,000 SF at 4 in. = 2,000 x 4 / 12 / 27 = 24.7 CY
lumber: 20 pieces of 2x10 at 16 ft = 20 x (2 x 10 x 16 / 12) = 533 BF (nominal)
roof: 3,450 SF / 100 = 34.5 SQ
Board feet are calculated on nominal dimensions in common U.S. practice; check how your supplier prices.
Abbreviations in proposals
In proposals and scope letters, write units the way the customer uses them. Owners may not know SFCA or MBF, and GCs outside your trade may not know your fixture shorthand. Spell a term out once, followed by the abbreviation. Label the unit on every estimate row; many costly errors are SF priced as SY or LF priced as each.
Where RenderDraw fits
RenderDraw's AI takeoff reads legends and schedules and proposes quantities with their units and sheet sources for estimator review. Try a free sample takeoff, or see the takeoff measurement types guide.
