In Ecolego it is not necessary to specify units for each object. This entry is optional. However, the user should specify the unit of the simulation time step and materials (if materials are included in the model) before starting a simulation. The default unit for the simulation time step is Year but can be changed in the simulation settings window.

Entering units

Units are specified in the properties page when editing blocks. Some objects like compartments and transfers cannot be assigned units because they are implicit from the materials and time unit of the model. For instance, if the unit for the material “Arsenic” is set to “kg” and the simulation time unit is set to “year”, the unit of a compartment will be (kg) and the unit of a transfer will be (kg/year).

Use ^ to enter exponents, for example: m^2 s^-1 will be displayed as (m2 s-1)

Unit suffix

To specify unit notations such as “freshweight” or “particle” you can use a ”.”. For example: kg.fw will be displayed as (kgfw).

The unit suffix is important for unit checking, see below.

Unit conversions

There is no automatic unit conversion in Ecolego. You can however convert units when you enter parameter values by using the constants editing tool. The units supported are listed below.

Unit checking

By default Ecolego will not perform unit checking. To enable this feature, open the errors and warnings page of the preferences screen.

The unit checking algorithm is strict - there might be cases (for instance with empirical relationships) where the unit checker will report an error even if there is none. Also, when using suffixes, the unit checking algorithm will refuse to accept mixing of quantities. For instance, the expression rho(kg/m3) = m (kgpart)/V(m3) will fail because kg != kgpart.


The default unit for radionuclides is mol. The unit must be the same for all radionuclides, so when the unit is changed from mol to Bq for one radionuclide the unit of all other radionuclides will change.

Built-in units

sSecond kgKilogram mMeter
minMinute60 s uAtomic mass10-3/
6.02214199 1023 kg
ftFoot0.3048 m
hHour60 min meElectron mass9.10938188 10-31 kg ydYard3 ft
dDay24 h lbPound0.45359237 kg inInch1/12 ft
weekWeek7 d oz_avOunce1/16 lb ÅAngstrom10-10 m
monthMonth1/7 year ton_UKLong ton2240 lb uaAstronomical unit149597870691.0 m
yearYear31556952 s tMetric ton1000 kg lyLight year9.460528405 1015 m
Plane angle Area Volume
radRadian m2Square meterm2 m3Cubic meterm3
revRevolutionrad aAre100 m2 LLiter0.001 m3
°Degree angle1/360 rev haHectar100 a gallon_liquid_USGallon liquid US231 in3
'Minute angle1/60 ° bBarn10-28 m2 pint_liquid_USPint liquid US1/8 gallon_liquid_US
''Second angle1/60 ' Velocity fluid_ounce_USFluid ounce US1/16 pint_liquid_US
gradeGrade1/400 rev m/sMeter per secondm/s gallon_dry_USGallon dry US268.8025 in3
Solid angle MMach331.6 m/s pint_dry_USPint dry US1/8 gallon_dry_US
srSteradian Acceleration gallon_UKGallon UK4.54609 L
sphereSpheresr m/s2Meters per second squarem/s2 pint_UKPint UK1/8 gallon_UK
Temperature Pressure Substance
KKelvin PaPascalN m-2 molMole
CCelsiusK+273.15 atmAtmosphere101325 Pa atomAtom1/6.02214199 1023 mol
°RRankine5/9 K barBar100 kPa Frequency
°FFarenheit459.67 °R mm_HgMillimeter of mercury133.322 Pa HzHertzs-1
Force Energy Magnetic flux
NNewtonkg s-2 JJouleN m WbWeberV s
dynDyne10-5 N BtuBritish thermal unit1055.056 J MxMaxwell10-8 Wb
kgfKilogram force9.80665 N Btu_ThBritish thermal unit (thermochemical)1054.350 J Magnetic flux density
lbfPound force9.80665 N kb Btu_meanBritish thermal unit (mean)1055.87 J TTeslaW m-2
Power calCalorie4.1868 J GGauss10-4 T
WWattJ/s CalKilocalorie103 cal Inductance
hpHorsepower735.499 W ergErg10-7 J HHenryW/A
eVElectron-volt1.602176462 10-19 J
Electric current Electric charge Electric resistance
AAmpere CCoulombs A ΩOhmV/A
GiGilbert10/4π A eElectron1.602176462 10-19 C Electric conductance
Electromotive force FdFaraday1.602176462 10-19 3.3356 10-10 C FFaradC/V
VVoltW/A FrFranklin3.3356 10-10 6.02214199 1023C Capacitance
Luminous intensity Lumenous flux Illuminance
cdCandela lmLumencd sr lxLuxlm m-2
LaLambert10 4 lx
Activity Absorbed dose Dose equivalent
BqBequerels-1 GyGrayJ/kg SvSievertJ/kg
CiCurie3.7 1010 Bq rdRad0.01 Gy remRem0.01 Sv
RdRutherford106 Bq Catalytic activity Ionizing ability
katKatal RRöntgenC/kg

See also