Ask ten electrical contractors what the hardest part of their job is. Eight will say estimating. Not pulling wire, not dealing with inspectors. Estimating. Get it wrong and you either lose the bid or lose money on the job. No middle ground.
This guide walks through how to estimate electrical work the way it gets done in the field, from plan review through final submission. If you're new to running your own shop or trying to tighten up your process, this framework works.
Why Estimating Is the Hardest Part
Estimating is where your entire profit lives. Bid too high and the GC moves on to the next sub. Bid too low and you're working for free. Or worse, losing money while your crew thinks everything is fine. Every missed junction box, every run of MC cable you forgot to count, comes straight out of your margin.
The thing is, you're pricing work that doesn't exist yet. You're working from drawings that will change, on a schedule you don't control, with material prices shifting weekly. You need to be fast enough to bid multiple jobs per week. And accurate enough that your numbers hold up six months later when you're installing.
Step 1: Read the Plans and Specifications
Before you count a single device, read the entire set. Electrical sheets, mechanical sheets, architectural sheets, the spec book. Most estimators jump straight to the E-sheets and miss things buried in Division 26 or called out on the reflected ceiling plan.
Pay attention to the general notes, the abbreviation legend, and the spec sections on equipment and acceptable manufacturers. If the spec calls for a specific panel manufacturer and you price a cheaper alternative, your number is wrong before you start.
Mark up the drawings as you go. Flag anything unclear or contradictory. Those become RFIs or qualifications in your proposal. A question you ask before the bid is free. A question you ask after the contract is signed becomes a change order negotiation.
Step 2: Do Your Material Takeoff
The material takeoff is the foundation of the entire estimate. You're counting every device, every foot of wire, every stick of conduit, every panel, breaker, and connector on the project. Miss something here and it cascades through the whole bid.
Work through the takeoff systematically. Most estimators go sheet by sheet and count by category:
- Devices - receptacles, switches, dimmers, sensors, data outlets
- Lighting - fixtures, emergency lights, exit signs, controls
- Wire and cable - measure each home run, add vertical rises, add 10-15% for waste and routing
- Conduit and fittings - EMT, rigid, PVC, flex, plus couplings, connectors, straps, boxes
- Panels and breakers - main distribution, sub-panels, breaker schedules
- Special systems - fire alarm, low voltage, generator connections, EV chargers
Use a consistent unit of measure for everything. Counting receptacles is straightforward. Measuring wire runs is where most errors happen. Always scale off the drawings and add length for drops, rises, and slack.
Step 3: Calculate Labor Hours
Now you know what materials go into the job. Next you figure out how long it takes to install them. This is where NECA labor units come in. The National Electrical Contractors Association publishes labor unit data telling you how many hours it takes to install each type of device, each hundred feet of conduit, each panel, all under normal conditions.
The key phrase is under normal conditions. NECA units assume reasonable access, moderate ceiling heights, and a competent crew. If you're working in an occupied hospital, above a drop ceiling at 14 feet, or in a building with no elevator and the panel room is on the fifth floor, you need to adjust upward. Common adjustment factors include:
- Occupied building or restricted hours: 10-20% increase
- High work (above 10 feet): 10-15% per additional 10 feet
- Congested mechanical rooms: 15-25% increase
- Prevailing wage or union crew productivity differences
Multiply your material quantities by the adjusted labor units. You get total labor hours. Multiply by your burdened labor rate (wages plus taxes, insurance, benefits, and workers comp) and you have your labor cost.
Step 4: Price Materials
Get real quotes from your suppliers. Don't estimate material cost from memory or old price sheets. Copper prices move, fixture lead times change, and the panel you used on the last three jobs might be discontinued.
Send your takeoff to at least two distributors and ask for project pricing. Most electrical distributors will give you a better rate on a full job package versus one-off purchases. Keep track of lead times too. If a switchgear has a 20-week lead time and the schedule shows 12 weeks to rough-in, flag it now.
Apply your material markup on top of your cost. Most electrical subs mark up materials somewhere between 10% and 25% depending on the job size and how competitive the bid is. In other words, the markup covers your purchasing overhead, your warehouse, delivery coordination, and the inevitable material damage and theft on site.
Step 5: Add Overhead and Profit
Your direct costs (labor and materials) are only part of the picture. You need to cover overhead: your office rent, trucks, insurance, estimating time, accounting, software, and the dozens of hours you spend on bids you don't win.
And there's a distinction between markup and margin that trips up a lot of contractors. If you are not clear on the difference, read our markup and margin guide — the math matters more than most subs realize. A 20% markup on a $100,000 job gives you a $120,000 bid with $20,000 gross profit. But your margin on the job is only 16.7% ($20,000 / $120,000). If your overhead runs at 18%, you lost money.
Know your overhead rate. Track it quarterly. Then add profit on top. If you need a 25% gross margin to cover overhead and profit, your markup needs to be 33%. The formula: markup = margin / (1 - margin). Get this wrong and you'll be busy and broke.
Step 6: Review and Submit
Before you send the bid, review it with fresh eyes. Check your extensions. Quantity times unit price should equal the line total. Make sure your labor rate is current. Verify you included sales tax on materials if your state requires it.
Write clear qualifications and exclusions. State what is included and what is not. If the spec is ambiguous on a particular item, qualify it. Common exclusions include generator installation, fire alarm programming, trenching, and patching/painting after rough-in.
Double-check your scope matches the bid form. If the GC wants the price broken into phases or CSI divisions, format it accordingly. A clean, professional proposal wins ties. And once you win the job, your estimate breakdown becomes the foundation of your schedule of values — so structure it accordingly from the start.
Common Estimating Mistakes
After years of estimating, the same mistakes come up over and over. Here are the ones that cost real money:
- Leaving out wire - You counted the devices but forgot the home runs. Or you measured horizontal runs and missed the vertical drops from ceiling to switch height. Wire is often the single largest material cost on a job.
- Underestimating travel and mobilization time - A 30-minute drive each way with a two-man crew is two labor hours per day producing nothing. On a 3-month job, it adds up fast.
- Not accounting for waste - You won't use every inch of a 250-foot roll of Romex or every stick of EMT. Industry standard is 10-15% waste factor on wire and conduit. Leave it out and you're buying extra material out of your profit.
- Missing change order language - If your proposal doesn't specify how changes are priced (time-and-material rates, markup on change orders, minimum charges), you'll end up eating scope creep you should have billed for.
- Using old pricing - Material prices from three months ago aren't valid today. Always get fresh quotes for anything over a small job.
Making the Process Faster
Contractors who win consistently aren't better electricians. They're better estimators. They have systems: templates for common job types, a database of labor units adjusted to their crews, and supplier relationships for fast quotes.
So if you're still doing takeoffs on paper or pricing in a spreadsheet, you're leaving speed and accuracy on the table. We built NEC calculators and estimating tools into Faraday because we got tired of flipping through code books and second-guessing conduit fill calculations. If your current process slows you down, give it a look. It's free to try and built by people who have pulled wire.
Whatever tools you use, the fundamentals don't change: read the plans carefully, count everything twice, price with real numbers, and know your overhead. Get it right and estimating stops being the hardest part of the business. It becomes your competitive advantage.