First of all, using an International Phonetic Alphabet (IPA) auto-converter won't help you in learning your task; the only way to learn IPA transcription is to do it for yourself. In fact, to help embed the transcription in your mind (and psyche!), you would do well to turn off (momentarily) your SIL Keyman Keyboard Unicode Script writer and transcribe with handwritten symbols. It's really fun as well as effective for learning. In fact, it is most fun when you transcribe by hand the speach of your friends as they speak! This is very amusing for all as well as effective for learning.

Secondly, the best tool you can come to rely upon is your Cambridge English Pronouncing Dictionary. It contains IPA pronunciation spellings of both American English (US/AE) and British English (UK/BE). Simply look up a word as you would in a definitions dictionary to find the words phonetically spelled right there for you, complete with word stress marks.

Now, what you are actually asking is if there are any Internet sites that can help you with IPA transcription when you are having difficulty. Yes, there are two that I know of, but the Project-Modelino.com auto-converter is not fully reliable. The other one is the Weston.Ruter.net type-online application that displays all the IPA charts, including diacritic and tone marks, and permits you to select and type the appropriate symbols, diacritics and tonals. Pretty handy. I like it. Let's try it using one word of your example.

Bear in mind, some of the IPA spellings will vary according to whether you are transcribing a rhotic or a non-rhotic variety of English. American English (AE) is, at this point in time, a rhotic variety, that is AE prescribes the pronunciation of all /r/ phonemes. British English (BE) is a non-rhotic variety, not all /r/ phonemes are pronounced. When this is applied to {for}, after checking our Cambridge volume and typing on the Weston.Ruter.net typing application, we see that the AE IPA spelling is [fɔːr], while in BE, it is [fɔː].

Next, let's put part of your first sentence into the Project-Modelino converter. "For five days, more than 200 students and faculty members participated ..." becomes [fər ˈfaɪv ˈdeɪz ˈmɔr ðən 200 ˈstuːdənts ənd ˈfækəltiː ˈmembərz pɑrˈtɪsəˌpeɪtɪd].

From this, you can see {for} is not transcribed according to the Cambridge entries. The transcription [fər] is actually representative of an accented or a dialectal pronunciation (one often heard in the San Joaquin Valley of California, in fact), sounding something like the free steady-state /ɜː/ vowel in NURSE, although the schwa /ə/ sound is like that in bonus. Therefore, this transcription is unreliable; you would need to compare it symbol by symbol to your Cambridge (or other pronunciation dictionary) to correct inaccuracies.

Finally, using the same sentence portion, I'll give you the typed Weston.Ruter version of the correct IPA transcription for rhotic AE pronunciation. Note that {student} in AE has no /j/ glide whereas BE does [stjuːdənt].

[fɔːr faɪv deɪz mɔːr ðæn 200 stuːdənts ænd fæklti membərz pɑrtɪsəpeɪtɪd] (Cambridge English Pronunciation Dictionary)

You'll note there are also IPA differences in {more} {than} {and} and {faculty}, confirming that the Project-Modelino converter is unreliable.

Weston.Ruter.net

Project-Modelino.com

fɔr fajv dez mɔr ðæn 200 studənts ænd fækəlti mɛmbərz partɪsəpetəd ɪn 100 awərz əv pɑvərti baj spɛndɪŋ ən $ 30 ɑn fud tu ɪkspɪriəns wət ɪts lajk tu lajv ɑn fud stæmps.
partɪsəpənts tʊk ɑn ðə tʃæləndʒ baj lɪmətɪŋ ðɛmsɛlvz tu wən mil ə de, skɪpɪŋ milz ɒl təgɛðər, hævɪŋ tu sɛtəl fɔr tʃipər, lɛs nutrɪʃəs ɑpʃənz ænd dɪklajnɪŋ tu pərtʃəs ləgʒəriz ðev gron əkəstəmd tu.
lɑ skul əsɪstənt prəfɛsər əv klɪnəkəl ligəl ɛdʒəkeʃən dʒɛnəfər bɒm sɛd ðə əmawnt $ $ 27. 49 wəz tʃozən fɔr ðə 100 awərz bɪkɒz ɪt kɔrəspɑndz wɪθ haw ðə səpləmɛntəl nutrɪʃən əsɪstəns progræm ( snæp) dɪstrɪbjuts fud stæmps.
snæp kərəntli əlɑts ə kwɑləfɑjd hawshold əv wən snæp kərəntli əlɑts ə kwɑləfɑjd hawshold əv wən pərsən $ 200 ɪn fud stæmps ɛvəri mənθ, wɪtʃ, kət dawn tu ə spæn əv 100 awərz , kəmz awt tu $ 27. 49