If setting a fixed price on your advertisement does not give you enough control, then choosing the Dynamic Price with Formula option will allow you to enter your own equation for calculating a dynamic price.
The Roolo systems collect pricing information from the top exchanges around the world and use this information to constantly update the price shown against your advertisements.
Each market value that we collect is represented by a placeholder name, such as bitcoinaveragegbp_mid. Every time that these values are updated, they are inserted in to the formula that you entered and a current live price is determined.
Your formulas may contain certain operators and functions, described below, which allow you to specify an advertisement price relative to, or as a function of, any combination of the values that we collect.
+
Addition.

Subtraction
The – operator may also be used as a negation operator : e.g. 6 + (2) which would equal 4.
*
Multiplication
/
Division. Note that the result of a division operation results in a number that may have have a fractional part.
^
The ^ operator raises one number to the power of another. For example 2^3 evaluates to 8 (i.e. 2*2*2).
All of the logical operators compare two values and return 0 (Zero) if the comparison evaluates to false or 1 (One) if the comparison evaluates to true.
These operators are intended for use with the ‘If’ function.
<
LessThan. Is ‘true’ if the first operand evaluates to a smaller number than the second operand.
E.g. 4 < 8 would evaluate to 1 (True).
<=
LessThan or Equal to.
>
GreaterThan.
>=
GreaterThan or Equal to.
=, ==
IsEqualTo. Both of these operators make a simple comparison, the == operator is included for the comfort of developers used to programming languages that use this convention.
!=, <>
IsNotEqualTo.
E.g. 5 != 5 returns 0 (False) whilst 42 != 3 returns 1 (True).
Functions, expressed as a name followed by a pair of round brackets that may contain one or more comma separated values, are intended to simplify complex calculations and to enable you to construct more intelligent price formulae.
Each function parameter may be made up of other price values, operators or functions.
Please note that there must not be a space between the function name and the first opening bracket.
sin, cos, tan
Standard Trigonometric functions.
Each of these functions takes a single parameter which should evaluate to a number expressed in radians.
The constant ‘pi’ is defined to make trigonomic calculations easier.
asin, acos, atan
Trigonometric functions, taking a single parameter, returning a value in radians.
sqrt
Returns the square root of the single parameter given to it.
E.g. sqrt(9) evaluates to 3. Sqrt(4*4*4*4) evaluates to 16.
abs
Absolute. Returns the absolute (i.e. positive) value of the single parameter given to it.
ln, log
Natural Logarithm
trunc
Returns the integer part of the number given to it.
E.g. trunk(3.65) returns 3.
ceil
Returns the next highest integer value by rounding up the value passed to it if necessary.
E.g. ceil(1.1) returns 2 whilst ceil(5.5) returns 5.
floor
Returns the next lowest integer value by rounding down the value passed to it if necessary.
E.g. floor(1.1) returns 1 whilst floor(5.5) returns 6.
round
Rounds the given value to the nearest integer. .5 values round up.
sgn
For a given value, returns (1) if negative, 1 if positive or 0 if the parameter value is zero.
max
This function takes an unlimited number of parameters and will return the largest of the given values.
E.g. max(5,66) returns 66, max(1,33,77,3,56) returns 77.
min
This function takes an unlimited number of parameters and will return the smallest of the given values.
E.g. max(5,66) returns 5, max(1,33,77,3,56) returns 1.
average
This function takes an unlimited number of parameters and will return the average of the given values.
E.g. average(5,66) returns 35.5, average(1,33,77,3,56) returns 34.
if
This function takes three parameters :
If(condition, trueValue, falseValue)
If the condition value contains a nonzero (i.e. true) value, then the second ‘trueValue’ parameter is returned, otherwise the third ‘falseValue’ parameter is returned. This enables you to create conditional logic and the functions can, of course, be nested.
E.g. if(5 < 6, 7,8) returns 7 because 5 is less than 6 so the second parameter is returned.
or
Returns 1 (true) if any of the given parameters is true (i.e. not zero), otherwise it return 0 (false).
E.g. or(0, 5, 77, 0, 3) returns 1 (true).
and
Returns 1 (true) only if ALL of the given parameters are true (i.e. not zero), otherwise it return 0 (false).
E.g. and(1,2,3) returns 1 (true) whilst and(1,2,3,0) returns 0 (false).
not
This function takes a single parameter and returns 1 (true) if the given value is 0 (false), or 0 (false) if the given value is not zero (true).
fx
Fx(FromPrice, FromCurrency, ToCurrency)
This function is provided as a convenience for converting prices from one currency to another. The first parameter is the price to convert, the second parameter is the currency in which that price is denominated, the third parameter is the desired currency of denomination. The Third parameter can be omitted, in which case a price to USD is calculated.
E.g. Fx(100, GBP, EUR) would return the value of 100GBP converted to Euros.
Fx(bitstampusd_bid, USD, GBP) would return the current BitStamp USD Bid price, converted from US Dollars to British Pounds.
As well as fixed numbers and functions, your formulae can contain placeholders representing prices published by other markets. These placeholders can be used anywhere in your formula and a new price will be calculated each time any of them change.
The prices that we collect are all taken from the public APIs of each site.
The update frequency and availability of these prices is subject to the business practice and good will of the respective exchanges.
All of the placeholder prices are in the form :
<Exchange><Currency>_<price>
For example, Bitfinex USD Bid price has the placeholder : bitfinexusd_bid
The placeholders are not case sensitive.
Exchange
Currency(s)
Price(s)
Example(s)
Bitfinex
USD
Bid, Ask, Last
High, Low, Mid
bitfinexusd_bid
bitfinexusd_mid
Cryptopay
EUR
GBP
cryptopayeur_bid
cryptopayusd_high
BTC China
CNY
High, Low, Last
Mid, VWAP
btcchinacny_last
btcchinacny_mid
BTCe
RUR
Avg, Mid
btceeur_avg
btceusd_last
Coinbase
Bid, Ask
coinbaseusd_bid
coinbaseusd_ask
Bitbargain
Avg_1h
Avg_3h
Avg_6h
Avg_12h
Avg_24h
bitbargaingbp_avg_1h
bitbargaingbp_avg_12h
Igot
AED, AUD
EUR, GBP
HKD, INR
INR_India
KES, NZD
SGD, USD
Open
High
Low
Mid
igotusd_mid
igothkd_open
BitStamp
bitstampusd_bid
bitstampusd_ask
OKCoin
okcoincny_ask
okcoincny_low
Huobi
huobicny_high
huobicny_low
Bitcoin Average
AUD, BRL
CAD, CHF
CNY, EUR
GBP, IDR
ILS, MXN
NOK, NZD
PLN, RON
RUB, SEK
ZAR
bitcoinaverageaud_mid
bitcoinaverageusd_last
Local Bitcoins
(localbtc)
AED, ARS, AUD
BRL, CAD, CHF
CLP, CNY, COP
CZK, DKK, EUR
GBP, HKD, HRK
HUF, INR, IRR
JMD, KES, MXN
MYR, NGN, NOK
NZD, PEN, PHP
PLN, RON, RUB
SAR, SEK, SGD
THB, TRY, UAH
USD, VEF, XAF
LAST
AVG1
AVG12
AVG24
localbtcusd_last
localbtczar_avg1
ANX
CAD
HKD
JPY
NZD
SGD
Avg, Vwap
anxcad_vwap
anxcad_low
Kraken
High, High24,
Low, Low24,
Vwap, Vwap24
krakengbp_mid
krakenjpy_last
In addition to the market price placeholders, there are a number of system names that are there to help you further customise your prices.
Pi, e
Standard mathematical constants
timestamp
Returns the current time measured as seconds since 1 Jan 1970.
This is a Unix convention and equates to GMT.
Year
Four digit year of the timestamp date
Month
Month of the timestamp date, an integer between 1 and 12.
Day
Day of the timestamp date, an integer between 1 and 31.
Hour
Hour of the timestamp date, an integer between 0 and 24.
Minute
Minute of the timestamp date, an integer between 0 and 59.
Second
Second of the timestamp date, an integer between 0 and 59.
These values can be used with the logical operators and the IF function to, for example, adjust your prices when outside of normal hours.
There are placeholders for many international currencies using the standard ISO currency codes including, but not limited to :
AED, ARS, AUD, BRL, CAD, CHF, CLP, CNY, COP, CZK, DKK, EUR, GBP, HKD, HRK, HUF, IDR, INR, IRR, JMD, KES, MXN, MYR, NGN, NOK, NZD, PEN, PHP, PLN, RON, RUB, SAR, SEK, SGD, THB, TRY, UAH, USD, VEF, XAF, ZAR
These placeholders represent the amount of local currency that equals 1 USD, so to convert a price from Hong Kong Dollars to US Dollars, for example, the formula might be :
SomeHKDPrice / HKD
Which would result in the USD equivalent of the HK Dollar price. To convert the same price to GBP, you would need to convert to USD as above and then into Pounds Sterling:
(SomeHKDPrice / HKD) * GBP
or the equivalent : SomeHKDPrice * (GBP/HKD)
or using the FX function : fx(SomeHKDPrice, HKD, GBP)
To calculate the Average mid price of Bitstamp, BitFinex and Kraken USD prices :
Average(bitstampusd_mid, bitfinexusd_mid, krakenusd_mid)
To return that as a GBP Price :
Average(bitstampusd_mid, bitfinexusd_mid, krakenusd_mid) / GBP
Or
Fx(Average(bitstampusd_mid, bitfinexusd_mid, krakenusd_mid), USD, GBP)
To price off the BitcoinAverage GBP Mid price and adjust your price by +5 if the time (GMT) is before 9AM or After 6PM :
bitcoinaveragegbp_mid + if(or(hour < 9, hour >= 18), 5, 0)