Lambing calculator and sheep gestation chart
Sheep are pregnant for about 147 days, just under five months.
Put in the day the tups went in and see when the first lambs are due. Add the day they came out for the whole spread, cycle by cycle, and the dates to book the scanner. It works backwards too: pick the day you want lambing to start and it tells you when to put the tups in. Further down there's a gestation chart for the whole season that you can print for the shed wall.
Add it to see the whole lambing spread.
147 is the usual average. Change it if your ewes run shorter or longer.
Pick the date the tups went in.
This calculator does one group at a time
Agrianta keeps services, scans and lambings on each ewe's record, so the due dates for the whole flock are already worked out.
- Services recorded at the pen
- Record the tup and the date where it happens, even without signal.
- Scans next to the service
- Singles, twins and triplets go on each ewe's record, linked to the service they belong to.
- Due dates from your own records
- Expected dates come from each service and the pregnancy length, so you can plan the work weeks ahead.
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Sheep gestation chart for the 2026 to 2027 season
The first lambs due for each week of tupping from 1 August to the end of January, using the 147-day average. Ewes lamb a few days either side of the date. For another date, or the whole spread cycle by cycle, use the calculator above.
| Tups in | First lambs due |
|---|---|
| 1 Aug 2026 | 26 Dec 2026 |
| 8 Aug 2026 | 2 Jan 2027 |
| 15 Aug 2026 | 9 Jan 2027 |
| 22 Aug 2026 | 16 Jan 2027 |
| 29 Aug 2026 | 23 Jan 2027 |
| 5 Sep 2026 | 30 Jan 2027 |
| 12 Sep 2026 | 6 Feb 2027 |
| 19 Sep 2026 | 13 Feb 2027 |
| 26 Sep 2026 | 20 Feb 2027 |
| 3 Oct 2026 | 27 Feb 2027 |
| 10 Oct 2026 | 6 Mar 2027 |
| 17 Oct 2026 | 13 Mar 2027 |
| 24 Oct 2026 | 20 Mar 2027 |
| 31 Oct 2026 | 27 Mar 2027 |
| 7 Nov 2026 | 3 Apr 2027 |
| 14 Nov 2026 | 10 Apr 2027 |
| 21 Nov 2026 | 17 Apr 2027 |
| 28 Nov 2026 | 24 Apr 2027 |
| 5 Dec 2026 | 1 May 2027 |
| 12 Dec 2026 | 8 May 2027 |
| 19 Dec 2026 | 15 May 2027 |
| 26 Dec 2026 | 22 May 2027 |
| 2 Jan 2027 | 29 May 2027 |
| 9 Jan 2027 | 5 Jun 2027 |
| 16 Jan 2027 | 12 Jun 2027 |
| 23 Jan 2027 | 19 Jun 2027 |
| 30 Jan 2027 | 26 Jun 2027 |
Agrianta works these dates out for the whole flock from your own service records. Start your free trial
How the dates are worked out
- A ewe carries her lambs for 147 days on average, so the first lambs are due 147 days after the tups go in.
- A ewe that doesn't hold comes back into season 16 to 17 days later. The calculator splits the tupping period into 17-day cycles, and each cycle lambs in its own block. If you change the raddle colour every 17 days, each colour matches one block.
- Scotland's Farm Advisory Service suggests scanning 70 to 100 days after the tups go in, so that is the window shown.
- Treat the dates as a guide. If your ewes always come a few days early or late, change the pregnancy length to match your flock.
Sources
Common questions
How long are sheep pregnant?
About 147 days on average, or just under five months. Individual ewes lamb a few days either side, and breed, age and the number of lambs she carries all move it a little.
How do I work out when my ewes will lamb?
Add 147 days to the day the tups went in for the first lambs, and 147 days to the day they came out for the last. The calculator does both and splits the weeks in between into 17-day cycles.
When should I put the tups in?
Count back 147 days from the day you want the first lambs. For lambs from 1 April, the tups go in on 5 November.
When should I scan my ewes?
Scotland's Farm Advisory Service suggests 70 to 100 days after the tups go in. The calculator shows that window for your dates.
Last updated 4 November 2026