Menstrual Cycle Calculator in Google Sheets & Excel
Formula
The API generates detailed cycle calendars with phase information including menstruation, follicular, ovulation, and luteal phases for multiple upcoming cycles.
=VERVE("menstrualcycle", A2, "field", "last_period_date")=VERVE.CALL("menstrualcycle", A2, "field", "last_period_date")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.
=VERVE("menstrualcycle", "2024-01-01", "field", "last_period_date")=VERVE.CALL("menstrualcycle", "2024-01-01", "field", "last_period_date")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.
| Input | Type | Where it goes | Description |
|---|---|---|---|
last_periodRequired | string | argument 2 | First day of last menstrual period (YYYY-MM-DD) (e.g. 2024-01-01) |
cycle_length | integer | "cycle_length", value | Average cycle length in days (e.g. 28) |
period_length | integer | "period_length", value | Average period duration in days (e.g. 5) |
cycles | integer | "cycles", value | Number of future cycles to calculate (e.g. 3) |
Passing an option
=VERVE("menstrualcycle", A2, "cycle_length", 28)=VERVE.CALL("menstrualcycle", A2, "cycle_length", 28)What lands in your sheet
The "field" pair is what makes the formula resolve to one cell. The name is a dot-path from the table below, so swapping it is how you pull a different value — one formula per column.
Seeing everything at once
Drop the "field" pair and the formula returns the whole response instead: two columns, field name on the left and value on the right, spilling from the cell you typed in.
=VERVE("menstrualcycle", A2)=VERVE.CALL("menstrualcycle", A2)Good for finding out what a source returns, but it is not a formula you can fill down: the second row's table would land on top of the first's, and every cell after the first reads #REF! (#SPILL! in Excel). Keep one per sheet, or name a field. Leave the cells below and to the right empty.
Available fields
#PREMIUM(field) rather than a value, so a locked field never looks like a real answer.| Use as "field" | Type | Example cell value | Description |
|---|---|---|---|
last_period_date | string | First day of last menstrual period | |
cycle_length | number | Average menstrual cycle length in days | |
period_length | number | Average menstrual period duration in days | |
cycles_calculated | number | Total number of cycles calculated | |
cycles | array[3] | Array of calculated menstrual cycles with details | |
└ cycles.0.cycle_number | number | Sequential number of the cycle | |
└ cycles.0.period | object | Start, end and length of the period for this cycle | |
└ cycles.0.period.start_date | string | Start date of menstrual period | |
└ cycles.0.period.end_date | string | End date of menstrual period | |
└ cycles.0.period.duration_days | number | Duration of period in days | |
└ cycles.0.ovulation | object | Estimated ovulation date and which day of the cycle it falls on | |
└ cycles.0.ovulation.date | string | Predicted ovulation date in cycle | |
└ cycles.0.ovulation.day_of_cycle | number | Day of cycle when ovulation occurs | |
└ cycles.0.fertile_window | object | Range of days conception is possible in this cycle | |
└ cycles.0.fertile_window.start_date | string | Start of fertile window for conception | |
└ cycles.0.fertile_window.end_date | string | End of fertile window for conception | |
└ cycles.0.fertile_window.duration_days | number | Duration of fertile window in days | |
└ cycles.0.pms_phase | object | Range of days premenstrual symptoms are expected | |
└ cycles.0.pms_phase.start_datePremium | string | Start date of PMS phase | |
└ cycles.0.pms_phase.end_datePremium | string | End date of PMS phase | |
└ cycles.0.cycle_phasesPremium | object | Detailed breakdown of menstrual cycle phases | |
└ cycles.0.cycle_phases.menstrualPremium | object | The bleeding phase, with its dates | |
└ cycles.0.cycle_phases.menstrual.startPremium | string | Start date of menstrual phase | |
└ cycles.0.cycle_phases.menstrual.endPremium | string | End date of menstrual phase | |
└ cycles.0.cycle_phases.menstrual.descriptionPremium | string | Description of menstrual phase | |
└ cycles.0.cycle_phases.follicularPremium | object | From the end of the period to ovulation | |
└ cycles.0.cycle_phases.follicular.startPremium | string | Start date of follicular phase | |
└ cycles.0.cycle_phases.follicular.endPremium | string | End date of follicular phase | |
└ cycles.0.cycle_phases.follicular.descriptionPremium | string | Description of follicular phase | |
└ cycles.0.cycle_phases.ovulationPremium | object | The day the egg is released | |
└ cycles.0.cycle_phases.ovulation.datePremium | string | Ovulation date within cycle | |
└ cycles.0.cycle_phases.ovulation.descriptionPremium | string | Description of ovulation phase | |
└ cycles.0.cycle_phases.lutealPremium | object | From ovulation to the start of the next period | |
└ cycles.0.cycle_phases.luteal.startPremium | string | Start date of luteal phase | |
└ cycles.0.cycle_phases.luteal.endPremium | string | End date of luteal phase | |
└ cycles.0.cycle_phases.luteal.descriptionPremium | string | Description of luteal phase | |
└ cycles.0.statusPremium | string | Status of cycle relative to current date | |
└ cycles.0.days_untilPremium | object | Days until cycle phase occurs | |
└ cycles.0.days_agoPremium | number | Days since cycle phase occurred | |
current_status | object | Which phase today falls in and when the next period is due | |
└ current_status.phasePremium | string | Current menstrual cycle phase name | |
└ current_status.descriptionPremium | string | Description of current cycle phase | |
└ current_status.next_periodPremium | object | Date of next expected menstrual period | |
└ current_status.days_until_next_periodPremium | object | Days until next menstrual period starts | |
averages | object | Average cycle length, period duration and gap between periods | |
└ averages.cycle_lengthPremium | number | Average menstrual cycle length across periods | |
└ averages.period_durationPremium | number | Average menstrual period duration across cycles | |
└ averages.days_between_periodsPremium | number | Average days between menstrual period starts | |
disclaimer | string | Legal disclaimer about calculation accuracy |
Filling a whole column
Both platforms make one batched call for a column rather than one request per cell, and both cost the same — 1 credit per row looked up. How you write it differs, because the two runtimes batch at different points.
=VERVE("menstrualcycle", A2:A100, "field", "last_period_date")Give the arguments ranges and the answers spill down from the cell you typed in. Sheets custom functions run synchronously and in isolation, so dragged cells can't be coalesced — the range form is how a column becomes one call.
The "field" pair is required here: a per-row two-column table has nowhere to spill. Use a full column per input (A2:A100, not A2) — a single-cell reference is read as row 1 only, and the rest of the column comes back blank.
=VERVE.CALL("menstrualcycle", A2, "field", "last_period_date")Drag or double-click the fill handle — no range form and none needed. Excel's runtime is asynchronous, so the add-in coalesces the calls a fill produces into a single batched request on its own.
Don't hand VERVE.CALL a range: Excel flattens it into positional arguments, so A2:A100 arrives as a hundred separate arguments and the cell reads #ERR rather than filling.
Either way, column A holds your last_period values and the answers land beside them, one row each, blank rows 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 reads | What happened |
|---|---|
#ERR Not connected | No API key saved. Open the side panel and connect your account. |
#ERR Replace <name> with a cell or value | The preview formula was copied as-is. Swap the placeholder for a cell reference. |
#ERR No "x" in menstrualcycle | An 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 credits | The 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.
- Install the add-in for Google Sheets or Excel.
- Open the side panel and sign in, or paste a key from your dashboard.
- Type the formula above into any cell.
Other ways to use Menstrual Cycle Calculator
Set up Menstrual Cycle Calculator on VerveSheets, or reach the same source a different way. Your VerveSheets account and credits work on all of them — one key, one balance.
Frequently asked questions
Does Menstrual Cycle Calculator work in both Google Sheets and Excel?
Yes — the same source, the same arguments, the same result. Google Sheets calls it =VERVE("menstrualcycle", A2, "field", "last_period_date") and Excel namespaces it as =VERVE.CALL("menstrualcycle", A2, "field", "last_period_date"). Filling a whole column is the one place the two differ: Sheets takes ranges directly, Excel fills down.
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, on both platforms and however you fill it. Repeated identical lookups in the same column are charged once. Batching changes how many HTTP calls are made, never the credit count.
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.