Menstrual Cycle Calculator in SheetsMenstrual Cycle Calculator in Sheets

OnlineCredit Usage:1 per cell

Formula

The API generates detailed cycle calendars with phase information including menstruation, follicular, ovulation, and luteal phases for multiple upcoming cycles.

In a cell
=VERVE("menstrualcycle", A2)
In a cell
=VERVE.CALL("menstrualcycle", A2)

A2 holds the last_period you're looking up. Drag the formula down and each row resolves on its own.

With literal values

Nothing has to come from a cell — typed values work the same way.

Sheets
=VERVE("menstrualcycle", "2024-01-01")

Inputs

Required inputs are positional, in the order below. Everything else is passed as a "name", value pair after them — the same shape as SUMIFS.

InputTypeWhere it goesDescription
last_periodRequiredstringargument 2First day of last menstrual period (YYYY-MM-DD) (e.g. 2024-01-01)
cycle_lengthinteger"cycle_length", valueAverage cycle length in days (e.g. 28)
period_lengthinteger"period_length", valueAverage period duration in days (e.g. 5)
cyclesinteger"cycles", valueNumber of future cycles to calculate (e.g. 3)

Passing an option

Sheets
=VERVE("menstrualcycle", A2, "cycle_length", "28")

What lands in your sheet

With no "field" pair the formula spills the whole response as two columns — field name on the left, value on the right — starting at the cell you typed in. Make sure the cells below and to the right are empty.

Pulling one value

Add a "field" pair to get a single cell back instead of a table. The field name is the dot-path from the table below.

Returns last_period_date
=VERVE("menstrualcycle", A2, "field", "last_period_date")
Returns last_period_date
=VERVE.CALL("menstrualcycle", A2, "field", "last_period_date")

Available fields

Fields marked Premium need a paid plan. On the free plan those cells read #PREMIUM(field) rather than a value, so a locked field never looks like a real answer.
Use as "field"TypeExample cell valueDescription
last_period_datestring2024-01-01First day of last menstrual period
cycle_lengthnumber28Average menstrual cycle length in days
period_lengthnumber5Average menstrual period duration in days
cycles_calculatednumber3Total number of cycles calculated
cyclesarray[3]list of rowsArray of calculated menstrual cycles with details
cycles.0.cycle_numbernumber1
cycles.0.periodobject{…}
cycles.0.period.start_datestring2024-01-01
cycles.0.period.end_datestring2024-01-05
cycles.0.period.duration_daysnumber5
cycles.0.ovulationobject{…}
cycles.0.ovulation.datestring2024-01-15
cycles.0.ovulation.day_of_cyclenumber14
cycles.0.fertile_windowobject{…}
cycles.0.fertile_window.start_datestring2024-01-10
cycles.0.fertile_window.end_datestring2024-01-15
cycles.0.fertile_window.duration_daysnumber6
cycles.0.pms_phaseobject{…}
cycles.0.pms_phase.start_datestring2023-12-21
cycles.0.pms_phase.end_datestring2023-12-31
cycles.0.cycle_phasesobject{…}
cycles.0.cycle_phases.menstrualobject{…}
cycles.0.cycle_phases.menstrual.startstring2024-01-01
cycles.0.cycle_phases.menstrual.endstring2024-01-05
cycles.0.cycle_phases.menstrual.descriptionstringMenstruation
cycles.0.cycle_phases.follicularobject{…}
cycles.0.cycle_phases.follicular.startstring2024-01-06
cycles.0.cycle_phases.follicular.endstring2024-01-14
cycles.0.cycle_phases.follicular.descriptionstringFollicular phase - preparing for ovulation
cycles.0.cycle_phases.ovulationobject{…}
cycles.0.cycle_phases.ovulation.datestring2024-01-15
cycles.0.cycle_phases.ovulation.descriptionstringOvulation - most fertile day
cycles.0.cycle_phases.lutealobject{…}
cycles.0.cycle_phases.luteal.startstring2024-01-16
cycles.0.cycle_phases.luteal.endstring2024-01-28
cycles.0.cycle_phases.luteal.descriptionstringLuteal phase - preparing for next period
cycles.0.statusstringpast
cycles.0.days_untilobjectnull
cycles.0.days_agonumber715
current_statusobject{…}Which phase today falls in and when the next period is due
current_status.phasePremiumstringUnknownCurrent menstrual cycle phase name
current_status.descriptionPremiumstringDescription of current cycle phase
current_status.next_periodPremiumobjectnullDate of next expected menstrual period
current_status.days_until_next_periodPremiumobjectnullDays until next menstrual period starts
averagesobject{…}Average cycle length, period duration and gap between periods
averages.cycle_lengthPremiumnumber28Average menstrual cycle length across periods
averages.period_durationPremiumnumber5Average menstrual period duration across cycles
averages.days_between_periodsPremiumnumber28Average days between menstrual period starts
disclaimerstringThis calculator provides estimates only. Actual cycles may vary. Consult a healthcare provider for medical advice.Legal disclaimer about calculation accuracy

Filling a whole column

Hand the first argument a range instead of a cell and the add-in makes one batched call for the lot, then spills the answers down. That is faster than dragging the formula and costs the same credits — one per row looked up.

Rows 2–100 in one call
=VERVE("menstrualcycle", A2:A100, "field", "last_period_date")
Rows 2–100 in one call
=VERVE.CALL("menstrualcycle", A2:A100, "field", "last_period_date")

A2:A100 is the column of last_period values. The result spills down alongside it, one row per input, blanks skipped.

When a cell doesn't fill

A failed lookup returns readable text starting with #ERR rather than a spreadsheet error, because Excel cannot show a custom message on a real error — you would get a bare #VALUE! with no reason. The trade-off is that IFERROR() won't catch it; test with LEFT(cell, 4) = "#ERR" instead.

Cell readsWhat happened
#ERR Not connectedNo API key saved. Open the side panel and connect your account.
#ERR Replace <name> with a cell or valueThe preview formula was copied as-is. Swap the placeholder for a cell reference.
#ERR No "x" in menstrualcycleAn option name that this source doesn't take. The message lists the ones it does.
#ERR No data point "…"The "field" path isn't in the response. Check the dot-path against the table above.
#PREMIUM(field)The field exists but your plan doesn't include it.
#ERR Out of creditsThe month's credits are spent. Usage resets on your billing date.

Before the formula works

The add-in reads the API key you saved once in the side panel — the key never goes in the formula, so a shared sheet doesn't leak it and a collaborator without access simply sees the last calculated values.

  1. Install the add-in for Google Sheets or Excel.
  2. Open the side panel and sign in, or paste a key from your dashboard.
  3. Type the formula above into any cell.

Other ways to use Menstrual Cycle Calculator in Sheets

Set up Menstrual Cycle Calculator in Sheets on VerveSheets, or reach the same source a different way. Your VerveSheets account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an X-API-Key header, with SDKs for Node, Python and .NET.APIVerveReference →
Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKitReference →
Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContextReference →

Frequently asked questions

Does Menstrual Cycle Calculator in Sheets work in both Google Sheets and Excel?

Yes — the same source, the same arguments. Sheets calls it =VERVE("menstrualcycle", …) and Excel calls it =VERVE.CALL("menstrualcycle", …); that function name is the only difference.

Do the cells recalculate on their own?

They recalculate when the sheet does — on edit, on open, or on a manual recalc. Each recalculation is a fresh call and spends credits, so for a large static column it's worth copying the results and pasting them as values.

How many credits does a filled column cost?

1 credit per row looked up, whether you drag the formula or pass a range. The range form is one HTTP call instead of many, but the credit count is the same.

Can I share the sheet without sharing my key?

Yes. The key is stored against your account, not in the file. Collaborators see the values already in the cells; formulas only recalculate for someone who has connected their own account.

Why is a cell showing #ERR instead of an error?

So you can read the reason. Excel can't display a custom message on a real spreadsheet error, so the add-in returns the explanation as text on both platforms instead.

What's Next?

Continue your journey with these recommended resources

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