Sizing
What Size Inverter for a Campervan?
The inverter turns your van battery's DC power into the household AC your laptop, blender, and chargers expect. Pick it too small and it shuts off mid-use; too big and it wastes battery just sitting on. Here is the simple way to land on the right size the first time.
The formula for sizing a van inverter
You only need two numbers, and the bigger of the two wins:
Inverter size = the sum of the running watts you'll use at once, with enough surge headroom for your biggest motor or compressor at startup.
In plain terms: write down everything you might have plugged in and switched on at the same moment, add up their running watts, and pick an inverter rated a bit above that total. Then double-check one thing the running total hides: surge. A fridge compressor, a water pump, or a power tool can briefly pull two to three times its running watts the instant it starts. A good inverter lists both a continuous rating and a higher surge rating, and the surge rating has to cover that startup spike or the inverter will trip off exactly when the appliance kicks on.
Worked examples by van build
Three common setups, sized from real loads:
Small van: electronics and a fan (1000 to 1500W)
If your AC needs are a laptop, phone and camera chargers, a few lights, and a roof fan, your peak running total is small, maybe 150 to 300W at once. You don't strictly need a big inverter for that. A 1000W pure sine unit covers it with ease, and a 1500W gives you room for the occasional blender or small power tool. Many minimalist vans skip a hardwired inverter entirely and let a portable power station handle the AC outlets.
| Device | Running watts |
|---|---|
| Laptop | ~60W |
| Phone + camera chargers | ~30W |
| LED lights | ~20W |
| Roof fan | ~30W |
| Peak total at once | ~140W |
Pick: 1000W pure sine, or 1500W for headroom.
Mid-size van: the everyday all-rounder (2000W)
This is where most full-time van builds land. You want to charge electronics, run a fan, occasionally use a blender or a small coffee maker, and maybe run a single induction burner for cooking, just not all at the same instant. A 2000W pure sine inverter handles each of these with margin and covers the surge when the fridge compressor cycles on. It is the most common van inverter size for good reason.
| Device | Running watts |
|---|---|
| Blender (burst) | ~500W |
| Laptop + chargers | ~90W |
| 12V fridge (compressor surge handled separately) | ~50W |
| Lights + fan | ~50W |
| Peak total at once | ~700W (with surge headroom to 2000W) |
Pick: 2000W pure sine.
Cooking van: fridge plus induction (3000W and up)
If you want to cook on an induction cooktop while the fridge, lights, and a charger are also running, your simultaneous load climbs fast. A single portable induction burner alone peaks near 1800W. Add a kettle or a second burner and you're past what a 2000W unit can sustain. Step up to a 3000W pure sine inverter so it isn't pinned at its limit every time you boil water, and make sure your battery bank and wiring can deliver the current that a 3000W draw demands.
| Device | Running watts |
|---|---|
| Induction burner (high) | ~1800W |
| 12V fridge | ~50W |
| Lights + fan + charger | ~120W |
| Peak total at once | ~2000W (size to 3000W) |
Pick: 3000W pure sine, on a battery and cabling sized to match.
Always buy pure sine for a van
There are two kinds of inverter output: pure sine and modified sine. Pure sine is clean power, identical to a wall outlet, and it is what you want for a van you actually live in. Modified sine is a cheaper, rougher waveform that can buzz, run hot, or even damage laptops, camera chargers, CPAP machines, and anything with a motor. The price gap is small and the risk is not worth it. Buy pure sine and don't look back. We break down exactly why in our pure sine vs modified sine guide.
Why you should oversize a little (but not a lot)
Round up from your peak load, don't shave it. An inverter run constantly near its continuous rating gets hot, less efficient, and works harder than one with breathing room, so a little headroom extends its life and covers the day you add a new gadget. But there is a real cost to going much bigger than you need: every inverter draws a small idle current just being switched on, and a 3000W unit idles higher than a 2000W one. Over a long boondock that wasted power adds up. The sweet spot is your honest peak load plus a sensible margin, which is why 2000W fits so many vans, not 4000W "just in case."
Match the inverter to the rest of your build
The inverter is one link in the chain. Once you know the size, see the units we'd actually buy in our best inverters for off-grid solar roundup, which sorts pure sine picks by build size from vans to whole-home 48V setups. To check how long your battery will actually run a given load, the run-time calculator does the math for you. And to plan the whole van system at once, the System Builder hands you a matched parts list, while the campervan wiring guide shows where the inverter sits in the layout.
We may earn a commission from links on this page, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.
The two sizes that fit most vans are the 2000W all-rounder and the 3000W cooking build:
Check 2000W Inverter Price on Amazon Check 3000W Inverter Price on Amazon
Related guides
- Pure Sine vs Modified Sine Inverters
- How to Wire a Campervan Electrical System
- 12V vs 24V vs 48V Off-Grid Systems
- What Can a 1000Wh Power Station Run?
Frequently Asked Questions
What size inverter do I need for a campervan?
For most van builds, a 2000W pure sine inverter is the sweet spot. It runs a laptop, lights, a fan, a blender, and a small induction burner one at a time with room to spare. Go to 1000 to 1500W if you only ever charge electronics and run a fan, and step up to 3000W only if you want to run an induction cooktop and a few other things at the same time.
Can a 2000W inverter run an induction cooktop?
Yes, a single portable induction burner peaks around 1800W, so a 2000W pure sine inverter handles it, just barely, with nothing else running. If you want the burner plus a kettle, a fridge, and lights all at once, size up to 3000W so the inverter is not constantly near its limit.
Do I need a pure sine wave inverter in a van?
Yes for almost everyone. Pure sine power is clean like a wall outlet and safe for laptops, camera chargers, CPAP machines, and anything with a motor. Modified sine inverters are cheaper but can buzz, run hot, or damage sensitive electronics, so they are rarely worth the small saving in a van you live in.
Should I size the inverter to running watts or surge watts?
Both. Add up the running watts of everything you will use at the same time to set the size, then check that the inverter's surge rating covers the biggest motor or compressor when it kicks on. A fridge or pump can pull two to three times its running watts for a split second at startup, and an undersized inverter shuts off right at that moment.
Is it bad to buy an inverter that is too big?
A little oversizing is good headroom, but a much larger inverter than you need wastes battery power. Inverters draw a small idle current just being switched on, and a big 3000W unit idles higher than a 2000W one. Size for your real loads plus some room to grow, not for the biggest number on the shelf.