As a frequent flyer and devout Muslim, businessman Abdalhamid Evans always comes up against the same challenge in the air: when to say his prayers.

Muslims are required to pray five times a day, at certain hours, but this schedule becomes complicated when crossing various time zones at thousands of metres above sea level.

"I usually don't pray when I am in a plane," said Evans, the London-based founder of a website that provides information on the global halal, or Islam-compliant, industry. "But lately I have been thinking that it is probably better to do them in the air than make them up on arrival."

The problem may be solved for travellers such as Evans thanks to an innovation called the Air Travel Prayer Time Calculator, developed by Singapore-based Crescentrating, a firm that gives halal ratings to hotels and other travel-related establishments.

Launched earlier this month, the online tool takes data such as prayer times in the country of origin, the destination city and in countries on the flight path and uses an algorithm to plot exact prayer hours during a flight.

Older software only allows Muslims to find their prayer hours according to a fixed position on land, and the absence of any tools that can be used to calculate during a flight has compromised many travellers.

"I knew there was lot of frustration among the travellers on this issue, but nobody had really attempted to solve it," Crescentrating chief executive Fazal Bahardeen said.

Before embarking on a trip, a Muslim traveller can now go to the online calculator in the Crescentrating website and input their departure airport, time of flight and destination.

The calculator then comes up with the prayer times set either in the local time of the airport of origin, the destination city or the country that the aircraft is flying over, which the traveller can then email to themselves to access later.