How many waffles do solar panels produce?

Quick: is 1.8 kWh a lot? Is 6.5 megajoules? What about 400W? Unless you do this for a living, those numbers mean nothing. Energy units were built for physics, not intuition.

Even Calories don’t fix it - “100 Calories” is just another abstract number. But the food behind the number is intuitive: everyone knows what eating a waffle feels like. And a waffle is just Joules in disguise:

1 \text{ kcal} = 4184 \text{ J}

So let’s measure the Sun and a solar panel in the only unit humans actually feel: breakfast. Let’s do the guesstimate.

Round 1: The Sky

First, our unit. A standard frozen waffle is about 90 kcal.¹ In real energy:

1 \text{waffle} \approx 90 \tfrac{\text{kcal}}{\text{waffle}} \times 4184 \tfrac{\text{J}}{\text{kcal}} \approx 0.38 \text{ MJ}

How energetic is the sky? At bright solar noon, one square meter of ground soaks up about 1,000 W.² Since a waffle is 0.38 MJ, a fresh one lands every:

\frac{0.38 \text{ MJ}}{1000 \text{ W}} = \frac{380{,}000 \text{ J}}{1000 \text{ J/s}} \approx 380 \text{ s} \approx 6 \text{ min}

One waffle every 6 minutes - almost as fast as the microwave. That is about 10 waffles an hour!

For a whole day, the sun only blazes near midday. Across a full day a square meter collects about 4.5 “peak sun hours” of energy³:

4.5 \text{ kWh} \times 3.6 \tfrac{\text{MJ}}{\text{kWh}} = 16.2 \text{ MJ} \approx 43 \text{ waffles}

So call it ~40 waffles a day raining down on each square meter of the planet.

Sky at noon: 10 waffles/h/m²
Per day: ~40 waffles/m²

Round 2: The Solar Panel

How much of that rain can solar panels grab? A standard 2026 panel is rated 400 W across about 1.7 m².⁴ ⁵ ⁶ At full sun that 1.7 m² is hit by 1,700 W, so the panel converts:

\frac{400 \text{ W}}{1000 \text{ W/m}^2 \times 1.7 \text{ m}^2} \approx 23\%

of the sunlight landing on it into electricity.⁷ In waffles, while the sun shines it turns out:

\frac{400 \text{ W} \times 3600 \text{ s}}{0.38 \text{ MJ}} = \frac{1.44 \text{ MJ}}{0.38 \text{ MJ}} \approx 3.8 \text{ waffles/h}

Per day, knowing we have ~4.5 peak sun hours per day, the daily haul is:

3.8 \tfrac{\text{waffles}}{\text{h}} \times 4.5 \text{ h} \approx 17 \text{ waffles/day}

Note that 17 waffles is about 1,550 Calories - close to three-quarters of a person’s daily recommended 2000 calories⁸, pulled from the sky for free in each solar panel. That’s quite insane!

Solar panel at noon: 3.8 waffles/h/panel
Per day: 17 waffles/panel ~ ¾ of a human daily intake

Watt?

Watt is the unit of power, which measures energy over time. One Watt is one joule per second ( $1 \text{ W} = 1 \text{ J/s}$ ). A waffle is 380,000 J, so to make one waffle, the material metabolic energy in the waffle itself, we’d ~106 W for an hour - or ~6,300 W for a minute. For intuition:

Thing	Power	Waffles
💡 LED bulb⁹	~10 W	0.1 / hour
💡 Old incandescent bulb⁹	60 W	0.6 / hour
💻 Laptop charger¹⁰	~65 W	0.6 / hour
☀️ Our solar panel	400 W	3.8 / hour
☕ Electric kettle¹¹	~1,500 W	0.24 / min
🔥 Electric oven¹²	~2,400 W	0.38 / min
⚡ Tesla Supercharger¹³	250,000 W	~40 / min

So our panel is capped at a few bright bulbs, while a Supercharger inhales ~40 waffles a minute.

Filling a Pool

Could the sky itself fill a swimming pool with waffles? A backyard pool holds about 50 m³.¹⁴ A round waffle (~11 cm across, ~1.3 cm thick) is a small cylinder of $\frac{11²\pi}{4}\times1.3\approx124cm³$ , so the pool fits:

\frac{50 \text{ m}^3}{124 \text{ cm}^3} \approx 400{,}000 \text{ waffles}

If a pool sits out in the open, catching the full ~40 waffles a day from the sun on each of a surface area ~32 m² of surface¹⁴ - about 1,400 waffles a day. Filling it:

\frac{400{,}000}{1{,}400 \text{ /day}} \approx 300 \text{ days}

So a sunny pool gets enough energy per year to get completely overfull of waffles. A typical room is close to these 50 m³ (a bit less typically), so you can also imagine your bedroom getting filled with waffles in under a year.

Bonus: the Menu

The waffle earns its keep as a unit because the usual snacks sit right next to it: a banana (105 kcal), an apple (95 kcal) and an egg (72 kcal) are each about one waffle.¹⁵ ¹⁶ So at full sun, the sun’s ~10 waffles an hour is also roughly ten bananas, ten apples, or ten eggs every hour.

The Big Mac is the outlier at 550 kcal - about 6 waffles each - so at noon the sun manages about one and a half Big Macs per hour.¹⁷

Interactive Calculator 💡

The Verdict

A solar panel pulls about 17 waffles of energy a day out of sunlight - roughly three-quarters of what a person eats, or about 4 waffles an hour while the sun is up. The sun is far more generous still: ~10 waffles an hour on every square meter at noon, almost all of which we never use.

You can’t eat the electricity, of course. But next time someone mentions a roof with 20 panels, you can translate: that is roughly 15 people’s worth of daily meals, falling from the sky.

Sources

¹ Kellogg’s Eggo Homestyle Waffles (SmartLabel): 180 kcal per 2 waffles. https://smartlabel.kelloggs.com/Product/Index/00038000402401

² Alternative Energy Tutorials: 1,000 W/m² is the solar irradiance at the Earth’s surface at solar noon on a clear day - “one full sun” (Standard Test Conditions). https://www.alternative-energy-tutorials.com/photovoltaics/standard-test-conditions.html Irradiance peaks near solar noon (Penn State EME 812). https://courses.ems.psu.edu/eme812/node/644

³ Daily insolation ≈ 4.5 kWh/m²/day = 16.2 MJ (peak-sun-hours, as above⁵). Top-of-atmosphere solar constant is 1,361 W/m² (NASA / Kopp & Lean 2011). https://earth.gsfc.nasa.gov/climate/projects/solar-irradiance/science

⁴ EnergySage, How Much Energy Does a Solar Panel Produce? (97% of 2025 quotes are 400-460 W). https://www.energysage.com/solar/solar-panel-output/

⁵ Nautilus Solar (400 W × 4.5 peak sun hours = 1.8 kWh/day). https://nautilussolar.com/blogs/how-much-energy-does-a-solar-panel-produce

⁶ A typical 400 W residential panel measures about 1.7 m × 1 m ≈ 1.7 m² (≈67 × 39 in). https://solarpanelquestions.com/how-big-is-a-400w-solar-panel-key-facts-and-insights/

⁷ EnergySage: top residential panels ≈ 20-23% efficient. https://www.energysage.com/solar/solar-panel-output/

⁸ U.S. FDA, How to Understand and Use the Nutrition Facts Label: 2,000 calories a day is used as a general guide for nutrition advice. https://www.fda.gov/food/nutrition-facts-label/how-understand-and-use-nutrition-facts-label

⁹ LEDVANCE, LED Bulb Wattage Equivalent: 60 W incandescent, ~8-10 W LED equivalent. https://www.ledvance.com/en-us/professional-lighting/insights/blog/lighting-basics/what-is-the-equivalent-wattage-for-led-bulbs

¹⁰ Anker: average laptop charger 65 W (~45-100 W). https://www.anker.com/blogs/chargers/how-many-watts-does-a-laptop-charger-use

¹¹ PowerInverters: standard kettle 1,200-1,500 W (UK 240 V up to ~3,000 W). https://powerinverters.com/electric-kettle-power-consumption

¹² Energy Use Calculator: ovens 1,000-5,000 W, ~2,400 W average. https://energyusecalculator.com/electricity_oven.htm

¹³ Tesla V3 Supercharger: up to 250 kW. https://hysunpower.com/blogs/news/how-many-watts-does-a-tesla-charger-take

¹⁴ A typical European backyard pool is about 8 × 4 m - a ~32 m² surface - and at a standard ~1.5 m depth that gives 8 × 4 × 1.5 ≈ 48 m³, rounded to ~50 m³ (about the same as a typical room). https://oasisbiosistema.com/en/blog/pool-sizes/ ; https://deependpools.co.uk/blogs/news/swimming-pool-size-whats-right-for-you

¹⁵ Banana: USDA via Food Network, medium banana 105 kcal. https://www.foodnetwork.com/how-to/packages/food-network-essentials/how-many-calories-in-a-banana Apple: USDA FoodData Central (FDC ID 1750340), medium apple (182 g) ≈ 95 kcal. https://caleye.fit/blog/calories-in-apple/

¹⁶ Large egg ≈ 72 kcal (USDA).

¹⁷ Big Mac sandwich = 550 kcal (CalorieKing; McDonald’s own current figure is 580 kcal). https://www.calorieking.com/us/en/foods/f/calories-in-sandwiches-burgers-big-mac-burger/atwb2iT2QqiH7k3guoeslg