To call to a BTTB phone, dial Like this:
IDD Prefix of the country FROM which you are calling - Country Code of Bangladesh (880) - Area Code without the leading zero - Phone number.
DO NOT press the leading zero of the area code. For example the area code of Dhaka is 02. But when you call from overseas to Dhaka, do not press the zero (0), just press 2. So, if you want to call 8151234 at Dhaka, press: (IDD prefix)88028151234

List of the IDD prefix for most of the countries of the world is given in a table below. Press the IDD prefix of the country FROM which you are calling. If you are using a Prepaid Telephone Card or VOIP, you may not need to dial an IDD prefix or you may have to dial a different IDD prefix. Please read the instruction of the Telephone Card or VOIP provider that you are using.

List of the Country Code for most of the countries of the world is given in a table below. Use the Country Code for the country TO which you are calling.

To call to a Mobile phone in Bangladesh, dial Like this:
IDD Prefix of the country FROM which you are calling - Country Code of Bangladesh (880) - Mobile phone number without the leading zero (1721251234).
DO NOT press the leading zero of the mobile phone number.
If you want to call 01721251234 at Grameen Phone, press: (IDD prefix)8801721251234
If you want to call 01552512345 at Tele Talk, press: (IDD prefix)8801552512345

To make an international call from Bangladesh:

To call to a Fixed line phone or Home phone in another country dial like this:
IDD Prefix of Bangladesh - Country Code of the country TO which you are calling - Area Code without the leading zero - Phone number

The IDD Prefix for the countries included in the EISD (Economy International Subscribers' Dialing) list is: 012

If you are calling to Australia, in the Sydney area and the phone number is 92661234 , then you should dial: 012-61-2-92661234 [IDD Prefix for EISD country is: 012 - Country Code of Australia is: 61 - Area Code of Sydney is: 02 - Phone number is: 92661234]. The City Code of Sydney is: 02. But you should NOT press the leading zero (0) of the city code.

If you are calling to a country that is NOT in the EISD list, you should use the normal IDD prefix of Bangladesh, which is: 00 (and in this case do not press 012).

For the EISD list, please visit the BTTB website: http://www.bttb.net/    OR    http://www.bttb.gov.bd/home/main/rates/EISDrate.htm

To call to a Mobile phone or Cell Phone dial like this:
IDD Prefix of the country FROM which you are calling - Country Code of the country TO which you are calling - Mobile or cell phone number without the leading zero.

To make an international call from any country of the world:
Follow the same system mentioned above.
 
To call to a Land Phone or Home Phone dial like this:
IDD Prefix of the country FROM which you are calling - Country Code of the country TO which you are calling - Area Code without the leading zero - Phone number

To call to a Mobile Phone or Cell Phone dial like this:
IDD Prefix of the country FROM which you are calling - Country Code of the country TO which you are calling - Mobile or Cell Phone number without the leading zero.

You just need to know the IDD Prefix of the country FROM which you are calling and the Country Code of the Destination country TO which you are calling. International Country Codes and IDD Prefixes of most of the countries of the world are given below:

 

Country Name (With satellite systems)	Country Code (look for the country TO which you are calling)	IDD Prefix (look for the country FROM which you are calling)
Afghanistan	93	00
Albania	355	00
Algeria	213	00
American Samoa	1-684	011
Andorra	376	00
Angola	244	00
Anguilla	1-264	011
Antarctica	672
Antigua	1-268	011
Argentina	54	00
Armenia	374	00
Aruba	297	00
Ascension	247	00
Australia	61	0011 (Voice calls) 0015 (Fax calls - Telstra) 0018 (Telstra special rates) 0019 (Fax calls - Singtel Optus)
Australian External Territories	672	00
Austria	43	00
Azerbaijan	994	00
Bahamas	1-242	011
Bahrain	973	00
Bangladesh	880	00 012 for EISD countries
Barbados	1-246	011
Barbuda	1-268	011
Belarus	375	8~10
Belgium	32	00
Belize	501	00
Benin	229	00
Bermuda	1-441	011
Bhutan	975	00
Bolivia	591	0010 (ENTEL) 0011 (AES COMMUNICATIONS BOLIVIA) 0012 (TELEDATA) 0013 (BOLIVIATEL)
Bosnia & Herzegovina	387	00
Botswana	267	00
Brazil	55	0014 (Brasil Telecom) 0015 (Telefonica) 0021 (Embratel) 0023 (Intelig) 0031 (Telemar)
British Virgin Islands	1-284	011
Brunei Darussalam	673	00
Bulgaria	359	00
Burkina Faso	226	00
Burundi	257	00
Cambodia	855	001
Cameroon	237	00
Canada	1	011
Cape Verde Islands	238	0
Cayman Islands	1-345	011
Central African Republic	236	00
Chad	235	15
Chatham Island (New Zealand)	64	00
Chile	56	00
China (PRC)	86	00
Christmas Island	61-8	0011 (Telstra)
Cocos-Keeling Islands	61	0011
Colombia	57	005?? Orbitel 007?? ETB 009?? Telecom #555?? Bellsouth #999?? Comcel
Comoros	269	00
Congo	242	00
Congo, Dem. Rep. of  (former Zaire)	243	00
Cook Islands	682	00
Costa Rica	506	00
C? d'Ivoire (Ivory Coast)	225	00
Croatia	385	00
Cuba	53	119
Cuba (Guantanamo Bay)	5399	00
Cura缯font>ao	599	00
Cyprus	357	00
Czech Republic	420	00 95200 (Discount carrier)
Denmark	45	00
Diego Garcia	246	00
Djibouti	253	00
Dominica	1-767	011
Dominican Republic	1-809 and 1-829	011
East Timor	670	00
Easter Island	56	00
Ecuador	593	00
Egypt	20	00
El Salvador	503	00 144+00 Telefonica
Ellipso (Mobile Satellite service)	8812, 8813	00
EMSAT (Mobile Satellite service)	88213
Equatorial Guinea	240	00
Eritrea	291	00
Estonia	372	00
Ethiopia	251	00
Falkland Islands (Malvinas)	500	00
Faroe Islands	298	00
Fiji Islands	679	00
Finland	358	00, 990, 994, 999
France	33	00 (France Telecom) 40 (TELE 2) 50 (OMNICOM) 70 (LE 7 CEGETEL) 90 (9 TELECOM)
French Antilles	596	00