Convert Celsius to Romer in seconds.

Ever tried reading a 300-year old Danish cookbook and stumbled over temperature instructions like "Bake at 60 degrees Romer"? Suddenly, your modern oven’s Celsius settings seem useless. That’s where understanding Celsius to Romer conversions becomes weirdly practical. But even if you’re not recreating Viking-era recipes, this conversion offers a fascinating peek into how science stumbled toward standardized measurements.

Unit definitions

What is a celsius (°C)?

The Celsius scale, named after Swedish astronomer Anders Celsius, sets water’s freezing point at 0°C and boiling point at 100°C (at sea level). It’s the go-to scale in most countries for weather, cooking, and science. Fun fact: Celsius originally proposed 0° for boiling and 100° for freezing, but it was flipped after his death.

What is a romer (°Rø)?

The Romer scale was invented by Danish astronomer Ole Romer in 1701. He used brine’s freezing point as 0°Rø and water’s boiling point as 60°Rø. It’s quirky, inconsistent, and barely used today. But back in the 18th century, it was cutting-edge tech for brewing and weather tracking.

Conversion formula

To convert Celsius to Romer:
°Rø = (°C × 21/40) + 7.5
Or simplified: Multiply Celsius by 0.525, then add 7.5.

Example calculations

1. Converting 20°C to Romer:
   20 × 0.525 = 10.5
   10.5 + 7.5 = 18.0°Rø
   (Perfect room temperature for fermenting beer, according to 1700s Danish brewers.)
2. Converting 100°C (boiling water) to Romer:
   100 × 0.525 = 52.5
   52.5 + 7.5 = 60.0°Rø
   (Matches Romer’s original boiling point definition!)

Conversion tables

Celsius to Romer

Romer to Celsius

From stargazing to sauerkraut: The Romer scale’s odd journey

Ole Romer didn’t set out to create a temperature scale. He was too busy calculating the speed of light by timing Jupiter’s moons (which he nailed within 25% of the modern value). But in 1701, Copenhagen needed better thermometers for its booming beer industry. Romer’s solution used two fixed points: freezing brine (0°Rø) and boiling water (60°Rø). The scale spread through Scandinavia but had a fatal flaw: brine’s freezing point varies with salt concentration. By 1742 Anders Celsius proposed his more reproducible water-based scale, though his original version was upside-down. The switch to today’s 0°C freezing/100°C boiling happened posthumously, giving Celsius all the glory while Romer became a historical footnote. Still, without Romer’s work, Fahrenheit might never have developed his scale, which dominated English speaking countries for centuries.

Interesting facts

1. Beer motivated innovation: Romer created his scale to help Copenhagen brewers maintain consistent fermentation temps.
2. Fahrenheit’s muse: Daniel Fahrenheit visited Romer in 1708 and used his scale as a basis for early Fahrenheit experiments.
3. Speed of light side quest: Romer’s astronomical work indirectly helped Einstein’s theories, 200 years later.
4. Thermometer tyranny: Denmark enforced Romer scale use until 1850, delaying Celsius adoption.
5. Cheese connection: Some traditional Danish cheesemakers still reference Romer temps in aging processes.

FAQ