Use this medieval manor farming calculator to estimate crop yields, livestock output & peasant feeding capacity for a 12th–14th century English manor
The medieval English manor was the basic unit of agrarian organisation from the Norman Conquest (1066) until the Black Death (1348–51). A "hide" — roughly 120 acres — was the traditional unit of land sufficient to support one free peasant family. The open-field three-field rotation system, spreading from the 11th century, divided the manor's arable land into three great fields: winter grain (wheat/rye), spring grain (barley/oats), and fallow. Domesday Book (1086) records around 5,000 manors in England, averaging 5–10 hides each. Medieval wheat yields of around 3:1 to 5:1 seed-to-harvest ratio (roughly 6–12 bushels per acre) were far below modern yields of 40+ bushels per acre. Beyond the lord's third, peasants also owed a church tithe and paid a toll to have their grain milled — obligations this calculator models as a cascading series of deductions.
Enter your manor's size in hides (1 hide ≈ 120 acres), select the soil quality for your region, and set the number of peasant households. Choose your crop rotation system and adjust the sliders to set the percentage of arable land under each crop type — wheat, rye, barley, and oats must total 100%. Input your livestock numbers, pick a harvest quality modifier, and click Calculate Manor Output. The tool instantly shows total food energy produced, the peasants' retained share after seed corn and manorial dues, feeding capacity, food-security duration in months, and a detailed crop-by-crop breakdown.
Understanding medieval food production isn't just an academic exercise — it reveals the extraordinary precariousness of life before industrialised agriculture. This calculator's own default 5-hide, 20-household manor computes to roughly a 29% surplus in a normal year — but switch the harvest-quality selector to "Famine year (×0.5)" and the same manor swings to a projected 27% shortfall. That single switch, representing real conditions during years like 1315–1317, is the difference between comfortable feasting and genuine hunger.
Historians, game designers building historically grounded strategy games, teachers preparing unit plans, and historical fiction writers all benefit from this medieval manor farming calculator. If you're running a tabletop RPG set in medieval Europe, you can use the Food Security Duration figure to decide whether a siege or blockade will starve a village in weeks or in over a year. If you're writing a novel, you'll understand why a drought in July caused genuine terror. The numbers also explain medieval social structures: the lord's third wasn't arbitrary greed — it was one layer of a fixed cascade of deductions (seed, church tithe, lord's rent, mill toll) that left peasants with well under half of what they actually grew.
This calculator uses historically documented yield ratios and unit conversions drawn from 12th–14th century English manorial records (including the Bolton Priory accounts and Walter of Henley's Husbandry, c.1280).
Arable acres: 1 hide × 120 acres × rotation efficiency (three-field = 66.7% productive, two-field = 50%, intensive = 85%).
Gross crop yield (bushels): Acres under crop × yield per acre × soil modifier × weather modifier, using wheat 8, rye 9, barley 10, and oats 11 bushels per acre.
Bushel weights & calories: Historical bushels varied in weight by grain — wheat 60 lb (27.2 kg), rye 56 lb (25.4 kg), barley 48 lb (21.8 kg), oats 32 lb (14.5 kg). At roughly 3,300–3,900 kcal per kilogram of whole grain, that works out to approximately 90,000 kcal per bushel of wheat, 81,000 for rye, 72,000 for barley, and 57,000 for oats.
Distribution of the gross harvest (applied as a uniform simplification across all four crops, since real manorial accounts varied by parish and year):
Livestock caloric contribution: Cattle = 1,200 kcal/day (milk + occasional slaughter); Sheep = 300 kcal/day (milk, wool, meat); Pigs = 400 kcal/day (autumn mast slaughter estimate). Peasants keep roughly 80% of this output, with the remaining fifth owed to the lord as rent-in-kind, heriot, or pannage dues.
Food security duration = (households actually supportable ÷ resident households) × 12 months — an estimate of how many months of the year the retained food supply could fully cover subsistence needs.
Take a 5-hide manor (600 acres total) using three-field rotation with average soil, a normal harvest, and 20 resident peasant households. Arable land = 600 × 0.667 ≈ 400 acres. Split across the default crop mix (35% wheat, 20% rye, 25% barley, 20% oats), the manor produces a gross harvest of roughly 3,722 bushels — about 1,121 bushels of wheat, 720 of rye, 1,001 of barley, and 880 of oats.
From that gross harvest, peasants first set aside 25% as seed corn (930 bushels), then pay a 10% church tithe (372 bushels) and the lord's third of what remains (806 bushels), and finally lose about 1/16 to the manorial mill toll (101 bushels) when grinding their own grain. That leaves roughly 1,512 bushels — worth about 114 million kilocalories — for the 20 households to actually eat. Add their 80% share of livestock output (24 cattle, 80 sheep, 20 pigs ≈ 17.8 million kcal) and the peasants have roughly 132 million kilocalories to live on: enough to support about 26 households for a full year — a modest ~29% surplus over the 20 households actually resident, or about 15.5 months of food security. Switch the harvest-quality selector to "Famine year (×0.5)" and that same manor swings to a projected 27% shortfall, illustrating just how quickly medieval communities could tip from comfortable surplus into hunger.
A hide was the standard English land unit from the Anglo-Saxon period, theoretically defined as the amount of land sufficient to support one free peasant family for a year. In practice it ranged from 40 to 240 acres depending on region and soil quality, but 120 acres became the standard administrative definition by the time of the Domesday Survey in 1086. This calculator uses 120 acres per hide as its base.
The two-field system left half the manor's land fallow each year to restore fertility — only 50% was productive. The three-field system rotated winter crops, spring crops, and fallow across three fields, meaning 67% of the land was productive each year. This 33% increase in productive acreage, combined with the nitrogen-fixing effect of spring legumes, dramatically increased total output and helped support the population growth of the 12th–13th centuries.
Calorie values are derived from real bushel weights (60 lb for wheat, 56 lb for rye, 48 lb for barley, 32 lb for oats) multiplied by typical whole-grain caloric density, giving roughly 90,000, 81,000, 72,000, and 57,000 kcal per bushel respectively. Livestock figures are estimates based on zooarchaeological evidence and contemporary agricultural treatises. Treat all results as reasonable educational approximations rather than precise historical measurements.
Yes — that's one of this tool's primary use cases. The "Food Security Duration" card converts the manor's retained food supply directly into months of coverage, so you can decide whether a siege or blockade starves a village in weeks or lets it hold out for over a year. A normal-harvest result above 12 months means the village has real reserves; a famine-year result under 9 months means it's already in crisis by midwinter.
This calculator models a cascading deduction: 25% of the gross harvest is reserved as seed corn, then a 10% church tithe is taken, then the lord claims one-third of whatever remains (about 21.7% of the original gross), and finally roughly 1/16 is lost to the mill toll when peasants grind their own grain (about 2.7% of gross). Combined, the church, lord, and miller together claimed around 34% of the gross harvest — or nearly 46% of the grain left once seed corn was set aside.
Selecting the "Famine year (×0.5)" harvest modifier halves gross crop yields, mirroring documented conditions during the Great Famine of 1315–1317. For the calculator's default 5-hide, 20-household manor, this turns a normal-year surplus of about +29% into a projected shortfall of roughly -27%, meaning several households would face genuine hunger by late winter without external grain imports.
HistoryCalc