The pteranodon isn’t in the 2014 SRD 5.1; this is its stat block from the SRD 5.2.
How many pteranodons for a fight?
A pteranodon is worth 50 XP. Using the 2024 encounter budgets (SRD 5.2), this is how many pteranodons fit each difficulty for a party of four characters of the same level. A dash means even one would be over the budget.
Party level
Low
Moderate
High
1st
4
6
8
2nd
8
12
12+
3rd
12
12+
12+
Budgets add up every monster’s XP, so you can swap some for other creatures of the same total. Try other party sizes and mixes in the encounter calculator.
How the pteranodon compares at CR 1/4
Against the 32 other challenge 1/4 monsters in the SRD 5.1, the pteranodon has more hit points than 10 of them, which makes it a little frailer than most at its CR. See every CR 1/4 monster.