"Challenge Rating (CR) summarizes the threat a monster poses to a group of four player characters. Compare a monster’s CR to the characters’ level. If the CR is higher, the monster is likely a danger. If the CR is lower, the monster likely poses little threat. But circumstances and the number of player characters can significantly alter how threatening a monster is in actual play. The Dungeon Master’s Guide provides guidance to the DM on using CR while planning potential combat encounters."

Challenge rating means nothing – it doesn't really compare to anything else except that one monster is more challenging than another.

Defining challenge rating by the monsters who possess it in FOF.

Why challenge rating? Why not levels?

Monster types (minion, normal, elite, solo) are so much easier! Why not those?

The scaling challenge of particular challenge ratings. CR 2s are my favorite.

https://slyflourish.com/what_does_cr_mean.html

Changes in challenge ratings in D&D 2024.

A focus on experience-based encounter building.

The Lazy Encounter Benchmark

An encounter may be deadly if the sum total of monster challenge ratings is greater than 1/4th of the total of character levels, or 1/2 if the characters are 5th level or above.

A single monster might be deadly if its challenge rating equals the average level of the characters, or 1.5x of average character levels if the characters are 5th level or above.

Write down the total character levels.
Divide by 4 if they're 1st to 4th level.
Divide by 2 if they're 5th level or above.
Write down 1.5 x the average of character levels to keep in mind for a single monster.

If characters are particularly powerful, consider the following modifiers to the benchmark:

at 11th level, multiply the total of character levels by .75 for your encounter benchmark.
At 17th level and above, the benchmark equals the sum total of character levels. don't divide by anything.

Scott Gray's approach: Add total character levels. Divide by 4. Multiply by tier (1, 2, 3 or 4).

Scale the benchmark by pretending there's an extra character or one fewer characters as desired.

Advantages of the Lazy Encounter Benchmark

It scales with the number of characters
It scales with a mixed level among characters
It scales with monsters of different challenge ratings
It scales well with the number of monsters.
It's easy to remember and calculate during the game. No tables or software needed.
It's flexible. You can modify it easily if its swaying too easy or too hard.

What About the D&D 2024 Encounter Building Guidelines?

They probably work fine.
It undervalues lower CR monsters compared to the LEB.
It overvalues higher CR monsters compared to the LEB.
You can't keep it in your head, you have to look at a chart.
It's designed as a budget instead of only being used as a warning light.

Do You Need a Benchmark?

Maybe not. Start with the monsters that make sense for the story and situation in the game. The LEB gives you this little warning light if things get too unintentionally hot.