Harmonizing a hymn in four parts means taking a tune the congregation already knows and giving soprano, alto, tenor, and bass something they can sing under it. The job is smaller than writing a new anthem and larger than typing the melody into a notation file. You decide the key for this choir, where the chords change, and which cadence the last line will land on. Then you listen, because a hymn that looks finished on the page can still fall apart when the basses meet the refrain.
A generated SATB draft can do the mechanical placement. CantuStudio keeps the imported melody in the soprano and proposes alto, tenor, and bass around it. That draft is a first pass for you to review. It does not clear copyright, and it does not know which section is thin this month. If you do not have the right to arrange the hymn, stop before you print parts. The steps below assume the tune is public domain or already yours to arrange.
Start from the tune the room already sings
Write the melody down before you touch the other voices. A hymn tune is usually a short phrase that repeats, with a refrain the congregation will sing whether or not the choir is ready. If you cannot hum the whole tune from memory, you do not yet know where the harmony has to be obvious. Mark the breaths a speaker would take. Those breaths are where the choir will want a chord that feels like a comma or a period, not a chord that is still traveling.
Keep the melody in the soprano for a congregational hymn. People find the tune by ear from the highest line. Moving it to the tenor for one verse can be a real arranging choice, and the arranging guide is where that texture belongs. For a straight four-part harmonization, leave the tune where the room expects it. When a draft is generated, the same rule is already in the file: the imported melody stays in the soprano so you are reviewing harmony, not hunting for a tune that wandered.
Name the stanza you are actually setting. A four-stanza hymn does not need four different harmonizations on Sunday morning. Set one stanza cleanly, then decide whether stanza three earns a quieter voicing or a different bass. If every stanza is a new puzzle, the choir spends rehearsal learning your curiosity instead of the text. One reliable harmonization, sung in tune, beats four clever ones that never get past bar six.
Choose the key by singing the edges
Play the melody in the key printed in the hymnal, then sing the highest soprano note and the lowest bass note you expect. If the sopranos grimace, or the basses drop out, the printed key is a piano key, not a choir key. Transpose before anyone memorizes the old one. A semitone is often enough. A whole tone is common for a volunteer group. Do this out loud. A key that looks familiar on the staff can still sit a third too high once four parts are filled in.
The range check used on a CantuStudio draft allows soprano from C4 to D5, alto from F3 to C5, tenor from B2 to G4, and bass from E2 to D4. That window is the edge of what the draft may print. It is not a comfortable tessitura for a Sunday choir. Keep most soprano notes between E4 and D5, most altos between A3 and B4, and treat a tenor G4 or a bass E2 as a short peak, not a place to live for a whole verse. If the only way the chord works is on those edges, the key is still wrong.
Meter comes with the key decision. Most traditional hymns sit in four-four or three-four, and the chord changes with the bar, not with every syllable. Write the time signature down before you harmonize, because harmonic rhythm depends on it. A tune in three-four that you accidentally feel in four-four will put the cadence on the wrong beat, and the choir will breathe in the middle of the word you cared about. Count one phrase with the text, not only with the piano.
Put chords on the beats the ear is waiting for
A hymn does not need a new chord on every note. Many tunes hold one chord across two or three melody notes and change when the bar begins, or when the text turns. Walk the melody and mark only the strong beats: beat one, and in four-four often beat three. Ask which chord the congregation would expect there. Tonic at the start of a line, dominant when the line asks a question, tonic again when the line answers. If you cannot name the chord on beat one, the inner voices have nothing honest to stand on.
Functional harmony is enough for most hymns. Tonic, subdominant, and dominant, with a clear cadence at the end of the stanza, will carry the text. A secondary dominant is a color you add because one word deserves it, not a habit you apply to every bar. The SATB harmonization guide goes further into inversions and how the bass announces the chord. This page only asks you to decide the chord before you decorate it. A beautiful alto line under the wrong chord is still the wrong chord.
Write the bass as soon as the chords are chosen. On the first beat of a phrase, a root or a clear inversion tells the choir where they are. A bass that only stamps roots will sound like a drum, so after the leap let it step. Do not ask the alto to explain the harmony. If you mute the soprano and the bass still tells you the progression, the harmony is doing its job. If the bass is a string of leftover chord tones, go back to beat one and choose the root again.
Fill alto and tenor so they can be sung alone
Alto and tenor complete the triad. Their default motion is a step or a held common tone. A leap in an inner voice is allowed when the chord actually changes color, and it should be repaired by a step in the other direction. If the alto is a row of repeated notes for eight beats, the section will drift, even though every note is legal. Give that line a small shape into the cadence: a neighbor tone, a step up when the text lifts, a rest when the soprano needs to be heard alone.
Spacing matters as much as the chord tones. Keep soprano and alto within an octave, and alto and tenor within an octave, so the upper voices sound like one choir. Tenor and bass may sit farther apart, because the bass often needs the root lower than the rest of the chord. A wide gap between alto and tenor makes a hymn sound hollow in a carpeted room. Close that gap before you add a passing tone. The voice-leading guide is the longer treatment of common tones, tendency tones, and crossings. Use it when a bar is correct and still feels stiff.
Check non-chord tones the way a singer hears them. A passing tone on a weak beat that resolves by step is ordinary hymn writing. A note that is not in the chord, sitting on a strong beat, and not resolving, is the thing the voice-leading check is built to flag. Do not call it expression until it behaves like a neighbor, a passing tone, or a suspension that was prepared. The same check flags parallel fifths and octaves, including a twelfth, and it does not treat contrary motion as a parallel. The parallel-fifths guide is the place to learn the distinction before you argue with the report.
Listen to the draft one voice at a time
Generate or write the four parts, then do not send the file. Play it. Mute the soprano and ask whether alto, tenor, and bass still make sense as music. Mute everyone except the tenor and sing that line on a neutral syllable. A part that only works when the melody is loud is not finished. The same pass catches a parallel that fused two sections and a leap the cautious singer will not find in the dark. Fix the bar in the file the same day. Next week is too late, because the choir will have memorized the version you already rejected.
A CantuStudio draft is that first pass, not the arrangement you hand out. The melody stays in the soprano. The report can flag parallel fifths, parallel octaves, voice crossing, range, and a non-chord tone on a strong beat. A rest breaks the parallel comparison. The report does not know your text stress, your theology, or which tenor is out. You still decide whether the cadence is the one you promised. If the last chord surprises the room, change it before rehearsal. Save the one unusual harmony for a word that deserves it, then resolve in a way the section can find without the piano.
The no-signup demo accepts a short melody, up to 16 notes, so you can try one phrase before you create an account. A free account includes a monthly harmonization allowance. Current limits are written on the English pricing page. Do not promise the choir a stack of new hymns until you have read that page. The SATB arranger and the hymn arranger are the product doors into the same drafting loop. The choir-director tool and the SATB arrangement app describe it from the product side. MusicXML harmonization is the door when the tune is already a MusicXML file rather than a line you typed.
Teach the cadence, then the rest of the stanza
In the room, teach the last line first. A hymn cadence the choir can feel coming, usually dominant to tonic, with the soprano arriving by step and the bass arriving on the root, gives every section a target. Once that bar is secure, back up a phrase. People learn a hymn from the place they already know, not from bar one of a cold reading. If the cadence is mush, no amount of alto detail earlier in the verse will save the stanza.
Have each section sing its line alone, then with the text, then with the other parts. When a bar collapses, it is usually a leap, a breath in the wrong syllable, or two voices that fused. Mark that bar on the paper the same afternoon. An arrangement that changes after the choir has memorized it costs more rehearsal than an arrangement that took one extra evening at the desk. Unison on the first line of the refrain, opening into four parts on the second line, is a legal tool when the group needs a pitch lock. It is arranging, and it belongs in the file, not as a spoken apology.
Export only the version you have already heard. PDF is the page someone prints. MIDI is the practice file a singer can loop. MusicXML is the score you keep editing in MuseScore, Sibelius, Dorico, or Finale, and that download is Pro. A free account does not receive the .musicxml file. The export guide explains which file to send to whom. Bring the reviewed hymn back to the arranging guide when you are deciding texture, who carries the tune, and what this particular choir can hold for a whole stanza.