Calculate Ovulation in Google Sheets & Excel

What this pulls

Estimate fertile windows from a cell. Returns ovulation date and fertile days — Sheets or Excel.

It's one of 250+ live sources you reach with a single =VERVE() function — served from APIVerve's production data engine, billed at 1 credit per resolved cell, and refreshed on whatever cadence you set. No API keys to wrangle, no scripts, no exports.

See it in a cell

A real example — the input you type, and the values you can pull from it. Click any cell to see the formula behind it.

ovulationcalculator.xlsxsample data

B2fx=VERVE("ovulationcalculator", A2, "field", "cycle_length")

Last period

Cycle length

Ovulation › Date

Disclaimer

Ovulation › Days from last period

2024-01-01

2024-01-15

This calculator provides estimates only. A…

click any cell to see its formula1 credit / cell

Ways to use it

One value per row

Fill =VERVE("ovulationcalculator", "2024-01-01", "field", "cycle_length") down a column and Calculate Ovulation returns a result for every row — a batch of live values in a single drag, no code.

Enrich data in place

Add Calculate Ovulation beside a table you already have to append its output right where your data lives, then sort, filter, or chart on it.

Stays fresh on its own

Set the sheet to refresh on a schedule and the calculate ovulation values keep themselves current without anyone re-typing.

Use it in your sheet

The same function works in both apps — install once, sign in with your key, and type it into any cell.

Google SheetsAdd-on

Install from the Workspace Marketplace, then drop the formula into a cell. Autocomplete suggests the source and its fields.

=VERVE("ovulationcalculator", "2024-01-01", "field", "cycle_length")

Microsoft ExcelAdd-in

Same source, same arguments, same key — in Excel on desktop, the web, or mobile. Excel namespaces it as VERVE.CALL. Drag to fill a whole column.

=VERVE.CALL("ovulationcalculator", "2024-01-01", "field", "cycle_length")

Optional inputs

Tune the result by adding name=value before the field argument — in any order. Leave one out and its default applies.

cycle_length
Average menstrual cycle length in days
=VERVE("ovulationcalculator", "2024-01-01", "cycle_length", "28")

Fields you can pull

Add a field name as the last argument to land just that value in the cell.

Ovulation › Date
=VERVE("ovulationcalculator", "2024-01-01", "field", "ovulation.date")
Ovulation › Days from last periodPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "ovulation.days_from_last_period")
Fertile window › StartPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_window.start")
Fertile window › EndPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_window.end")
Fertile window › Duration daysPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_window.duration_days")
Most fertile days › StartPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "most_fertile_days.start")
Most fertile days › EndPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "most_fertile_days.end")
Most fertile days › Duration daysPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "most_fertile_days.duration_days")
Fertile daysPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_days")
Fertile days › DatePremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_days.0.date")
Fertile days › Day relative to ovulationPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_days.0.day_relative_to_ovulation")
Fertile days › Fertility levelPremium
=VERVE("ovulationcalculator", "2024-01-01", "field", "fertile_days.0.fertility_level")

Premium marks data included on paid plans. On the Free plan a marked field is withheld and a marked input is ignored — either way the cell reads #PREMIUM(name) instead of a value, so a gated answer can never be mistaken for a real one. Everything unmarked works on every plan. Compare plans

Calculate Ovulation, answered

Everything you need to wire it into a sheet.

How do I pull Calculate Ovulation into Google Sheets?

Install the VerveSheets add-on, sign in once with your key, and type =VERVE("ovulationcalculator", "2024-01-01", "field", "ovulation.date") into any cell. The "field" argument names the value you want back, so the cell resolves to a single number or string you can chart, sort, or feed into another formula.

What data can I pull from Calculate Ovulation?

Calculate Ovulation returns ovulation.date — name any one of them as the "field" argument and that value lands in the cell. Leave the field out and the whole record spills into a two-column table instead.

Can I narrow what Calculate Ovulation returns?

Yes — Calculate Ovulation takes "cycle_length" as optional inputs. They go in as "name", value pairs after the required ones, in any order, so =VERVE("ovulationcalculator", "2024-01-01", "cycle_length", "28") shapes the result without changing anything else.

Which Calculate Ovulation fields need a paid plan?

ovulation.days_from_last_period, fertile_window.start, fertile_window.end and fertile_window.duration_days, plus 7 more are included from the Starter plan up. On the Free plan the cell returns #PREMIUM(field) rather than a wrong or empty value, so it's always obvious which one to upgrade for. Every other field works on Free.

Can I fill a whole column of Calculate Ovulation at once?

Yes. Put your last_period values down a column and point the formula at the range — A2:A50 instead of A2 — and one call returns a value for every row. Dragging the formula down works too, but the range form is a single billed call per column rather than one per cell.

How many credits does each Calculate Ovulation cell cost?

Each resolved cell costs 1 credit. A cell only re-bills when it actually refreshes, so a sheet you aren't touching doesn't keep charging.

Does Calculate Ovulation work in Excel as well as Google Sheets?

Yes — same arguments, same key, same fields. Excel namespaces custom functions, so the call is =VERVE.CALL() there and =VERVE() in Google Sheets; nothing else about it changes.

Calculate Ovulation

One value per row

Enrich data in place

Stays fresh on its own

Calculate Ovulation, answered

Put Calculate Ovulation in your next spreadsheet. Add the extension, paste the formula, and the cell keeps itself current.

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