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13 Letter Words Starting With IS

There are 63 valid 13 letter words that start with IS, drawn from NWL2023, CSW24, and Words With Friends. Sorted below by score, with the single highest scorer called out.

Highest Scoring 13-Letter Words

US Scrabble (NWL)

isocarboxazid - 34 points

UK Scrabble (CSW)

isocarboxazid - 34 points

Words With Friends

isocarboxazid - 36 points

13 Letter Words (63)

View all words starting with IS

Top 20 Highest-Scoring 13 Letter Words Starting With is

Point values shown for US Scrabble, UK Scrabble, and Words With Friends. The average across this full 63 word list is 66.3 combined points.

Rank Word US Scrabble UK Scrabble WWF Points Total
#1 ischiofemoral 23 23 25 71
#2 ischiofibular 23 23 26 72
#3 ischiorrhogic 24 24 25 73
#4 ischiovaginal 22 22 26 70
#5 isidiophorous 19 19 20 58
#6 islandologist 15 15 19 49
#7 ismaticalness 17 17 21 55
#8 isoagglutinin 15 15 21 51
#9 isoalloxazine 29 29 32 90
#10 isoantibodies 16 16 18 50
#11 isoasparagine 16 16 19 51
#12 isobarbituric 19 19 23 61
#13 isobarometric 19 19 22 60
#14 isobathytherm 26 26 25 77
#15 isobenzofuran 27 27 31 85
#16 isobiogenetic 18 18 22 58
🏆 #17 isocarboxazid 34 34 36 104
#18 isocheimenals 20 20 23 63
#19 isochromosome 22 22 24 68
#20 isochronising 19 19 22 60

Where 13 Letter Words Fit on the Board

At 13 letters, a word almost always uses your entire rack plus tiles already on the board these are realistically bingo-adjacent plays rather than everyday moves, which is why the list leans heavily on compound and suffixed forms (-nesses, -ation, -izing). If you're looking for words you can play more often, shorter lengths starting with IS will give you far more flexible options try 13 letter words starting with IS for a more practical middle ground.

Frequently Asked Questions

What is the highest-scoring 13 letter word starting with is?

isocarboxazid — worth 104 combined points (US Scrabble: 34, UK Scrabble: 34, Words With Friends: 36).

How many 13 letter words start with is?

63 valid words, combining entries from NWL2023, CSW24, and the Words With Friends dictionary.

Are 13 letter words realistic to actually play?

Only occasionally — you'd need most of your rack plus letters already on the board to reach 13 tiles. They're worth knowing for the rare bingo-extension play, but for regular turns, shorter is words will come up far more often.