When I write fiction, or even technical reports, I have a very difficult time catching myself unintentionally switching verb tenses. Does software exist that highlights verb tense (either by colour-coding them or something) to identify verb tense mistakes?

  • 2
    I don't know of any software, but this is what editing is for. Commented Sep 17, 2015 at 17:53
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    Even if it were possible to flag up tense misuse in a more accurate way than Word is able to do so, reading over your work should be the most important solution. Commented Sep 17, 2015 at 20:47
  • Can you tell me how such software could distinguish between "I read the book" (present tense) and "I read the book" (past tense)?
    – Robusto
    Commented Sep 24, 2015 at 11:21
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    @Robusto I figured it would highlight verbs it's uncertain about in a different colour.
    – Seanny123
    Commented Sep 24, 2015 at 12:06
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    None of these comments are on topic. The author asks a very clear, specific question. Please don't discuss here, whether or not the use of such a software would be helpful or not. Commented Aug 1, 2017 at 19:38

7 Answers 7


One inelegant way to do this:

  1. download https://nlp.stanford.edu/software/lex-parser.shtml
  2. run on your text (lexparser.sh yourtextfile.txt)
  3. split by tense. "VBD", "VBN" is past tense, "VBP", "VBZ","VBG" are present tense, "VBC", "VBF" future tense

Grammarly - It is web based, but also has browser and Word plugins. It will check all manner of grammar errors

  • 1
    Grammarly is nice, but unfortunately, it can't do, what the author is asking for specifically. Commented Aug 1, 2017 at 19:49
  • this does not do what the OP wants
    – ashleylee
    Commented Jan 30, 2019 at 16:06

Hemingway - Free web-version, paid download version. Identify clunky sentences, passive voice, unnecessary words. I think tense changes are included in the 'clunky' setting and passive voice is often an indicator of changing tense as well. Exports to HTML, Markdown, and Word.


AutoCrit has this feature. I've used Grammarly and it does not, but AutoCrit looks at tense changes and highlights each verb with color codes to make it clear where you change tense. Also point of view. Allows statistical comparisons with other fiction writers in your genre.


It's taking a sledgehammer to a nut, but the natural language toolkit could do it if your Python's decent.


This code was useful to me.

from nltk import word_tokenize, pos_tag

def determine_tense_input(sentence):
    text = word_tokenize(sentence)
    tagged = pos_tag(text)

    tense = {}
    tense["future"] = len([word for word in tagged if word[1] == "MD"])
    tense["present"] = len([word for word in tagged if word[1] in ["VBP", "VBZ","VBG"]])
    tense["past"] = len([word for word in tagged if word[1] in ["VBD", "VBN"]]) 

My final version looks like this:

text = word_tokenize(sentence)
tagged = pos_tag(text)
universal_tag = pos_tag(text, tagset='universal')
presents = [word for word in tagged if word[1] in ["VBP", "VBZ","VBG"]]

for i, x in enumerate(tagged[:]):
    if x[1] in ["VBP", "VBZ","VBG"] and universal_tag[i][1] in ["VERB"] and x[0] not in ["etc","[","]"]:

present_verbs = [" " + x for x in set(present_verbs)]
print(" \n".join(present_verbs))


Pro Writing Aid is great for checking nearly anything in your writing - just pick your analysis type. It's free to run it on up to 1,000 words at a time, so give a try.

Grammarly may work, but it's analysis isn't nearly as in-depth.

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    The tool is impressive, I tried it, thank you. However, it misses a feature: The one that the author has asked about. Commented Aug 1, 2017 at 19:40

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