Outside the United States, field capacity is usually measured in hectares per hour. The metric formula is even simpler than the imperial one. Hectares per hour equals width in metres times speed in km per hour times efficiency divided by 10. A 6 m cultivator at 10 km per hour and 80 percent covers 4.8 hectares per hour, so a 40 hectare field takes 8.3 hours. The rest of this guide explains why the divisor is 10, how to convert between acres and hectares, and how to plan a day in metric units.
Table of Contents
The Metric Formula and Why It Divides by 10
Hectares per hour equals working width in metres times speed in km per hour times efficiency divided by 10. The divisor comes from the size of a hectare. A machine 1 m wide travelling 1 km covers 1,000 m of length, so it covers 1 times 1,000, which equals 1,000 sq m. One hectare is 10,000 sq m, so 1,000 sq m is one tenth of a hectare. Dividing by 10 is therefore the same step as dividing by 8.25 in the imperial formula, only with rounder numbers. Read the where does 8.25 come from guide for the full derivation in both systems.
Work the example step by step. A 6 m cultivator at 10 km per hour and 80 percent efficiency gives 6 times 10 times 0.8 divided by 10, which equals 4.8 hectares per hour. A 40 hectare field takes 40 divided by 4.8, which equals 8.3 hours. Use the Acres Per Hour Calculator to try your own numbers. It has a metric switch that converts your entries and always shows both acres and hectares in the results, so a team that plans in mixed units can check the same job both ways.
Efficiency works the same way in metric as in imperial. It is the share of time spent covering new ground at full width, after allowing for turns, refills and stops. A large rectangular field with good logistics can run at 80 to 85 percent, while a small or irregular field can fall to 65 percent or lower. Read the understanding field efficiency guide for the full bands, from 55 to 65 percent on small fields up to 85 to 90 percent in ideal conditions.
Converting Between Acres and Hectares
One acre equals 0.4047 hectares, and one hectare equals 2.471 acres. To convert acres per hour to hectares per hour, multiply by 0.4047. To convert hectares per hour to acres per hour, multiply by 2.471. The same factors convert area, so a 100 acre field is 40.47 hectares, and a 100 hectare field is 247.1 acres. Keep the direction straight, because the two factors are easy to swap by mistake.
| From | To | Multiply by |
|---|---|---|
| acres | hectares | 0.4047 |
| hectares | acres | 2.471 |
| acres per hour | hectares per hour | 0.4047 |
| feet | metres | 0.3048 |
| mph | km per hour | 1.609 |
Width and speed need converting too. One foot equals 0.3048 metres, so a 30 ft header is 9.14 m wide, because 30 times 0.3048 equals 9.14. One mph equals 1.609 km per hour, so 5 mph is 8.05 km per hour, because 5 times 1.609 equals 8.05. Convert width and speed first, then use the metric formula. Do not mix a width in metres with a speed in mph, or a width in feet with a speed in km per hour.
The table below gives area conversions at a glance. Use it to check a field size given in the other system before you plan the time.
| Acres | Hectares | Hectares | Acres |
|---|---|---|---|
| 1 | 0.40 | 1 | 2.47 |
| 5 | 2.02 | 5 | 12.36 |
| 10 | 4.05 | 10 | 24.71 |
| 20 | 8.09 | 20 | 49.42 |
| 40 | 16.19 | 50 | 123.55 |
| 80 | 32.37 | 100 | 247.11 |
| 160 | 64.75 | 200 | 494.21 |
Metric Quick Reference
The table below gives hectares per hour for common machines at realistic speeds and efficiencies. Each row uses the metric formula, and each rate can be checked by hand in seconds.
| Machine | Width | Speed | Efficiency | Hectares per hour |
|---|---|---|---|---|
| Mower conditioner | 3 m | 10 km per hour | 80 percent | 2.40 |
| Rotary cutter | 2 m | 8 km per hour | 75 percent | 1.20 |
| Cultivator | 6 m | 10 km per hour | 80 percent | 4.80 |
| Seed drill | 4 m | 10 km per hour | 70 percent | 2.80 |
| Boom sprayer | 24 m | 12 km per hour | 70 percent | 20.16 |
| Combine | 9 m | 6 km per hour | 75 percent | 4.05 |
Read the table as a planning range, not as a promise. A 12 m sprayer at 15 km per hour and 80 percent covers 14.4 hectares per hour, because 12 times 15 times 0.8 divided by 10 equals 14.4. A 100 hectare block at 20.16 hectares per hour takes 100 divided by 20.16, which equals 5.0 hours, before allowing for refills. The acres per hour chart by equipment gives the same kind of table in imperial units, with mowers, cutters, tillage tools, planters, sprayers and combines side by side.
Planning a Day in Hectares Per Hour
Start with hectares, divide by hectares per hour to get hours, then divide by working hours per day to get days. A 120 hectare block with a 9 m combine at 4.05 hectares per hour takes 120 divided by 4.05, which equals 29.6 hours. At 10 working hours per day, that is about 3 working days, before allowing for weather. A 60 hectare block at the same rate takes 60 divided by 4.05, which equals 14.8 hours, or about 2 working days at 8 hours per day.
Refills and unloading still set the real limit, even in metric units. A boom sprayer at 20.16 hectares per hour will empty its tank long before the hour is up, and the refill cycle decides the real output for the day. Plan the tank loads and the refill time in the same units as the rate, and check the total mix volume from area times rate before the day starts. A plan that needs every hour to be a working hour with no stops and no weather is too tight. Build in a buffer, and cut the fields most at risk first.
Mixing Units Safely
Errors creep in when units are mixed, for example a width in metres with a speed in mph. Pick one system and convert everything before you calculate. The calculator metric switch does this automatically, but a hand calculation needs the same discipline. Write the units beside every number, and check the divisor matches the units: 8.25 for feet and mph, 99 for inches and mph, 10 for metres and km per hour. If the divisor and the units do not match, the answer will be wrong by a large factor, not by a rounding error.
The second risk is converting the rate but not the area, or the area but not the rate. A field of 40 hectares at 4.8 hectares per hour takes 8.3 hours, but a field of 40 acres at 4.8 hectares per hour is a different job, because 40 acres is only 16.19 hectares. Keep area and rate in the same system all the way through the plan, and convert only at the end if the team needs the other system for quoting. The how to calculate acres per hour guide shows the imperial method step by step, so you can check a metric plan against its imperial twin.
Common Mistakes in Metric Planning
The most common mistake is to use machine width instead of working width. Working width is the actual swath minus overlap, not the width on the spec sheet. Using the full width makes the estimate too high, and the job takes longer than planned. The second mistake is to use top speed instead of average speed held safely while working. The third mistake is to leave efficiency out, which gives a theoretical rate that no real field achieves. Use an efficiency that fits the field, and keep a log of real rates so the next estimate starts from measured numbers.
The fourth mistake is to round too early. Convert with the full factors, 0.4047 and 2.471, and round only the final answer. Rounding the conversion factor to 0.4 or 2.5 at the start can shift a large field by several hectares, and that shift changes the planned hours. The combine harvester productivity guide shows the same mistakes at harvest scale, where a wrong rate costs days.
Frequently Asked Questions
Q: What is the hectares per hour formula?
A: Hectares per hour equals width in metres times speed in km per hour times efficiency divided by 10. A 6 m cultivator at 10 km per hour and 80 percent covers 4.8 hectares per hour.
Q: Why does the metric formula divide by 10?
A: One hectare is 10,000 sq m, and a machine 1 m wide travelling 1 km covers 1,000 sq m, which is one tenth of a hectare. Dividing by 10 is that conversion.
Q: How do I convert acres per hour to hectares per hour?
A: Multiply by 0.4047. A rate of 12.27 acres per hour equals 4.97 hectares per hour, because 12.27 times 0.4047 equals 4.97.
Q: How do I convert hectares per hour to acres per hour?
A: Multiply by 2.471. A rate of 4.8 hectares per hour equals 11.86 acres per hour, because 4.8 times 2.471 equals 11.86.
Q: How long does it take to cover 40 hectares?
A: Divide area by rate. At 4.8 hectares per hour it takes 40 divided by 4.8, which equals 8.3 hours, before allowing for stops and weather.
Q: Can I mix metric width with mph speed?
A: No. Pick one system and convert everything first. A width in metres with a speed in mph gives a wrong answer, so convert the speed to km per hour or the width to feet before you calculate.
Metric planning is simpler than imperial planning, because the divisor is 10 and the conversions are clean. Use the metric formula, keep area and rate in the same system, and plan the day on the real rate after efficiency, refills and weather. A plan built that way finishes the hectares it promises, in either system.
