Service amperage, meter socket, panel size, grounding and breaker schedule for a panel upgrade.
Estimates are planning aids, not a professional quote. Double-check quantities and product coverage — and any local code or permit requirements — before you buy.
⚠ This connected-load buildup comes in at or under your existing 100A service. A load calculation this close doesn't automatically mean you need a bigger service — have a licensed electrician run the full NEC 220 calculation before paying for a full upsize; you may only need new breaker positions.
⚠ The utility must de-energize and physically disconnect service before this work starts, and reconnect and re-seal the meter after it passes inspection — schedule that outage window with them directly. Every jurisdiction requires a permit and inspection for a service change, and the vast majority require a licensed electrician to make the utility-side and panel connections even on an otherwise DIY-assisted job.
| Electrical | $786–$1,064 |
| Total | $786–$1,064 |
Excludes tools, delivery, tax and permit fees. Labor not included — this is a DIY materials estimate.
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About this calculator
Enter your home's square footage, the major appliances you're running, and how many circuits the new panel needs to hold, and the Panel Upgrade Calculator runs a real NEC 220 connected-load buildup — general lighting and receptacle demand, small-appliance and laundry circuits, and every major appliance at its full nameplate rating — to find the smallest standard service size that actually clears it, rather than guessing 100 versus 200 amps from house size alone.
Central electric heat is weighed against your cooling load rather than added to it, the way the code's larger-of test actually reads, so an electric furnace moves the answer without double-counting a condenser you never run at the same time. From there it sizes the parts nothing else on this site touches: the meter socket, the service-entrance conductor in copper or aluminum over your actual meter-to-panel run, a main breaker panel sized to your circuit count with spare capacity, and the grounding electrode system — conductor gauge, two ground rods, and the intersystem bonding bridge most DIY estimates skip entirely.
Step by step
A step-by-step walkthrough to go with your plan above. Follow the product instructions and any local code or permit requirements as you work.
Use the calculator to add up your general load, appliances and HVAC and get the smallest standard service size that clears it — this is the number that determines every part on the rest of the list.
Call your utility to schedule the outage window before you buy or schedule anything else. They control the drop conductor and the meter seal, and nothing downstream can start until they de-energize their side.
Mount the meter socket at the utility's required height and clearance, and run the overhead mast or underground conduit between the meter location and the panel.
Run the SE cable sized to your new service amperage through the mast or conduit, leaving enough slack at both ends for terminations without straining the conductors.
Set the main breaker load center at the required working clearance, land the service-entrance conductors on the main lugs, and land the neutral and equipment grounding bars per the panel's wiring diagram.
Drive both ground rods at least 6 ft apart, run the grounding electrode conductor sized to your service, and land the intersystem bonding bridge for the phone, cable and satellite grounds.
Move or land each branch circuit breaker into its space, torque every lug to the panel's spec, and fill out the door schedule as you go — not after, when it's easy to mislabel one.
Have the electrician confirm every connection, then call for inspection and the utility reconnect. Don't energize anything before the inspector signs off.
Equip the job
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Interior & Finishing
Answers
It comes from your actual connected load, not a rule of thumb per square foot. The standard method — NEC 220.82's optional calculation for dwellings — adds your general lighting and receptacle load, the required small-appliance and laundry circuits, and every major appliance at its full nameplate rating into a single total, then demand-factors that whole total at 100% of the first 10,000 VA and 40% of everything above it. Your heating or cooling load, whichever is larger, is added separately at 100%. This calculator runs that buildup and picks the smallest standard service size (100, 125, 150 or 200A) that clears the result, which is often smaller than homeowners expect.
It's headroom for the appliances you're running now and might add later. A 100A service can run a modest home comfortably but gets tight fast with electric heat, a large AC system, an EV charger and an electric range all on the same panel. 200A has become the practical default for most single-family homes today because it leaves room for those loads without a second upgrade a few years later, and 150A sits as a middle option for homes with moderate electric loads that don't need the full 200A jump.
Yes, in every jurisdiction we're aware of. A service change requires a permit, an inspection, and coordination with your utility to schedule the disconnect and reconnect — the utility has to physically pull or de-energize their side before anyone can safely work on the meter or panel. Prepping the site, trenching for an underground run, and staging materials are reasonable DIY tasks, but the utility connection and the final panel termination need a licensed electrician.
The grounding electrode conductor bonds your panel to the earth through driven ground rods, and its wire gauge is set by NEC Table 250.66 off the size of your service conductor — a bigger service needs a heavier ground wire. Code defaults to two rods driven at least 6 ft apart unless you test a single rod and prove it reads 25 ohms or less to ground, which most residential installs don't bother doing, so two rods is the practical default this calculator uses.
It happens more often than you'd expect, especially on a 100A service in a smaller or well-insulated home. If the load buildup comes in at or under what you already have, you may only need more breaker positions — a sub-panel or a bigger main panel at the same amperage — rather than a full service change with a new meter socket, entrance conductor and utility coordination. Have an electrician confirm with the full NEC 220 calculation before you commit to the bigger job.
Most upgrades keep whatever's already there, since converting from overhead to underground (or the reverse) is a separate, larger utility coordination job layered on top of the panel swap — new trenching or a new pole connection, not just a panel change. If you're building from scratch or genuinely have the choice, underground avoids storm damage and ice loading on the drop conductor but costs more upfront for the trenching, while overhead is cheaper and faster to install but more exposed to weather and tree limbs.