Utah, United States
Mountain Time
11:23 PM
Area Code
435
State / Province
Utah
Country
United States
Time Zone
Mountain Time
Area code 435 covers 111 cities and communities across Utah, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+14355550100">+14355550100</a><a href="tel:+14355550199">+14355550199</a>Look up which exchange in Utah a specific 435 number is homed to, and whether its block is wireline or wireless. See what a reverse lookup can establish before relying on the answer.
496 active prefixes in this area code, assigned as 3,185 thousands-blocks — pooling splits one prefix across several carriers, so each block is listed separately with the rate centre it is homed to, its carrier of record, and the switch that serves it.
Showing blocks 1–100 of 3,185
| NPA-NXX | Block | Rate centre | Type | Carrier (OCN) | Switch | LATA | LIR | Dates |
|---|---|---|---|---|---|---|---|---|
| 435-200 | 0 | Park City | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (7176) | SALT LAKE CITY | 660 | — | — |
| 435-200 | 1 | Park City | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - UT (117F) | SLKCUTMAX9X | 660 | — | — |
| 435-200 | 2 | Park City | Landline or VoIP | FIRSTDIGITAL TELECOM, LLC - UT (5727) | SALT LAKE CITY | 660 | — | — |
| 435-200 | 3 | Park City | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - UT (117F) | SLKCUTMAX9X | 660 | — | — |
| 435-200 | 4 | Park City | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - UT (117F) | SLKCUTMAX9X | 660 | — | — |
| 435-200 | 5 | Park City | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - UT (117F) | SLKCUTMAX9X | 660 | — | — |
| 435-200 | 6 | Park City | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (7176) | SALT LAKE CITY | 660 | — | — |
| 435-200 | 7 | Park City | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-200 | 8 | Park City | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | SLKCUTMAXKY | 660 | — | — |
| 435-200 | 9 | Park City | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-200 | A | Park City | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (7176) | SALT LAKE CITY | 660 | — | — |
| 435-201 | 0 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 1 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 2 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 3 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 4 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 5 | Richfield | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-201 | 6 | Richfield | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-201 | 7 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | 8 | Richfield | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-201 | 9 | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-201 | A | Richfield | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-202 | A | Logan | Wireless | UNION TELEPHONE COMPANY (013B) | SLKCUTMAXJY | 660 | — | — |
| 435-203 | 6 | Mount Pleasant | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-203 | 7 | Mount Pleasant | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-203 | A | Mount Pleasant | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-204 | A | Tooele | Landline or VoIP | SPOK, INC. (6630) | SLKDUTVF0MD | 660 | — | — |
| 435-205 | A | Montezuma Creek-Aneth | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | MNCKUTXC3MD | 981 | — | — |
| 435-207 | A | Tremonton | Landline | CITIZENS TELECOM-UTAH DBA FRONTIER COMM OF UT (4429) | TREMONTON | 660 | — | — |
| 435-209 | 0 | Milford | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-209 | 1 | Milford | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | — | 660 | — | — |
| 435-209 | 7 | Milford | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-209 | 8 | Milford | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-209 | 9 | Milford | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-209 | A | Milford | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-210 | 0 | Moab | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-210 | 1 | Moab | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-210 | 2 | Moab | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-210 | 4 | Moab | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-210 | 5 | Moab | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-210 | 6 | Moab | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-210 | 7 | Moab | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-210 | 8 | Moab | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-210 | 9 | Moab | Landline or VoIP | TELNYX LLC (073H) | WVCYUT145MD | 660 | — | — |
| 435-210 | A | Moab | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-212 | 0 | Hildale | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-212 | 1 | Hildale | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-212 | 2 | Hildale | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | — | 660 | — | — |
| 435-212 | 3 | Hildale | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-212 | 4 | Hildale | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-212 | 6 | Hildale | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | SLKCUT26CMD | 660 | — | — |
| 435-212 | 8 | Hildale | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-212 | A | Hildale | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-213 | 0 | Logan | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-213 | 1 | Logan | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-213 | 2 | Logan | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | SALT LAKE CITY | 660 | — | — |
| 435-213 | 3 | Logan | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | SLKCUTMAXKY | 660 | — | — |
| 435-213 | 4 | Logan | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-213 | 5 | Logan | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-213 | 6 | Logan | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-213 | 7 | Logan | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-213 | 8 | Logan | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-213 | 9 | Logan | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | SLKCUTMAXKY | 660 | — | — |
| 435-213 | A | Logan | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-214 | 0 | Park City | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-214 | 1 | Park City | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-214 | 2 | Park City | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | SALT LAKE CITY | 660 | — | — |
| 435-214 | 3 | Park City | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | SALT LAKE CITY | 660 | — | — |
| 435-214 | 4 | Park City | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-214 | 5 | Park City | Landline or VoIP | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM (7176) | SALT LAKE CITY | 660 | — | — |
| 435-214 | 6 | Park City | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-214 | 7 | Park City | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | SLKCUTMAXKY | 660 | — | — |
| 435-214 | 8 | Park City | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-214 | 9 | Park City | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-214 | A | Park City | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-215 | 0 | St George | Landline or VoIP | FIRSTDIGITAL TELECOM, LLC - UT (5727) | SALT LAKE CITY | 660 | — | — |
| 435-215 | 1 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-215 | 2 | St George | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | SALT LAKE CITY | 660 | — | — |
| 435-215 | 3 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-215 | 4 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-215 | 5 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-215 | 6 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-215 | 7 | St George | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC (7229) | SALT LAKE CITY | 660 | — | — |
| 435-215 | 8 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-215 | 9 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-215 | A | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | 0 | St George | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - UT (117F) | SLKCUTMAX9X | 660 | — | — |
| 435-216 | 1 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | 2 | St George | Wireless | T-MOBILE USA, INC. (6529) | DRPRUTKJ0MD | 660 | — | — |
| 435-216 | 3 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | 4 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | 5 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | 6 | St George | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-216 | 7 | St George | Landline or VoIP | ONVOY, LLC - UT (871E) | WEST VALLEY CITY | 660 | — | — |
| 435-216 | 8 | St George | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT (6571) | SLKDUTBTAMD | 660 | — | — |
| 435-216 | 9 | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-216 | A | St George | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - UT (3231) | SLKDUTYI3MD | 660 | — | — |
| 435-217 | 9 | Randolph | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | SLKCUTJC4MD | 660 | — | — |
| 435-217 | A | Randolph | Wireless | NEW CINGULAR WIRELESS PCS, LLC (6010) | — | 660 | — | — |
| 435-218 | 0 | St George | Landline or VoIP | CENTRAL TELCOM SVCS DBA CENTRACOM INTERACTIVE - NV (791D) | FOUNTAIN GREEN | 660 | — | — |
Block-level assignments from the North American Numbering Plan administrator, via localcallingguide.com.
Assigned Prefixes
496
Assignment Blocks
3,185
Rate Centers
111
Carriers of Record
61
| Type | Blocks | Share |
|---|---|---|
| Landline | 433 | 14% |
| Landline or VoIP | 1,307 | 41% |
| Wireless | 1,445 | 45% |
| Carrier | Blocks |
|---|---|
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT | 554 |
| ONVOY, LLC - UT | 501 |
| T-MOBILE USA, INC. | 454 |
| NEW CINGULAR WIRELESS PCS, LLC | 338 |
| QWEST CORPORATION | 231 |
| BANDWIDTH.COM CLEC, LLC - UT | 143 |
| LEVEL 3 COMMUNICATIONS, LLC - UT | 95 |
| CITIZENS TELECOM-UTAH DBA FRONTIER COMM OF UT | 75 |
| TELEPORT COMMUNICATIONS AMERICA, LLC - UT | 54 |
| PEERLESS NETWORK OF UTAH, LLC - UT | 51 |
| 51 other carriers | 689 |
Carrier of record for each block. Numbers ported to another carrier keep their original block assignment, so this is not a lookup of who serves a given number today.
| Rate Center | Prefixes | Blocks |
|---|---|---|
| St George | 52 | 442 |
| Logan | 45 | 332 |
| Park City | 32 | 251 |
| Tooele | 30 | 252 |
| Brigham City | 23 | 225 |
| Cedar City | 22 | 169 |
| Heber City | 13 | 136 |
| Richfield | 10 | 94 |
| Price | 9 | 36 |
| Castle Dale | 8 | 26 |
| Kamas | 8 | 64 |
| Nephi | 8 | 68 |
| Vernal | 8 | 38 |
| Beaver | 7 | 67 |
| Moab | 7 | 47 |
| Coalville | 6 | 52 |
| Bear River City | 5 | 53 |
| Duchesne | 5 | 12 |
| Howell | 5 | 18 |
| Roosevelt | 5 | 32 |
| Salina | 5 | 43 |
| Tremonton | 5 | 30 |
| Blanding | 4 | 22 |
| Brian Head | 4 | 32 |
| Delta | 4 | 39 |
| Fillmore | 4 | 29 |
| Glen Canyon City | 4 | 34 |
| Kanab | 4 | 18 |
| Manti | 4 | 16 |
| Monroe | 4 | 35 |
| Montezuma Creek-Aneth | 4 | 4 |
| Monticello | 4 | 23 |
| Panguitch | 4 | 21 |
| Parowan | 4 | 38 |
| Enterprise (Washington) | 3 | 22 |
| Ephraim | 3 | 16 |
| Garden City | 3 | 3 |
| Ibapah | 3 | 4 |
| Manila | 3 | 5 |
| Monument Valley | 3 | 5 |
| Mount Pleasant | 3 | 9 |
| Thompson | 3 | 7 |
| Altamont | 2 | 12 |
| Bicknell | 2 | 7 |
| Bluff | 2 | 9 |
| Boulder | 2 | 3 |
| Cannonville | 2 | 4 |
| Dangling Rope | 2 | 3 |
| Duck Creek | 2 | 4 |
| Dutch John | 2 | 2 |
| Eureka | 2 | 3 |
| Fairview | 2 | 9 |
| Fielding | 2 | 12 |
| Flattop | 2 | 12 |
| Green River | 2 | 7 |
| Halchita | 2 | 2 |
| Hanksville | 2 | 4 |
| Hildale | 2 | 19 |
| Holden | 2 | 7 |
| Jordanelle | 2 | 3 |
| Kanosh | 2 | 6 |
| La Sal | 2 | 7 |
| Lake Powell | 2 | 7 |
| Lynndyl | 2 | 12 |
| Meadow | 2 | 7 |
| Mexican Hat | 2 | 6 |
| Milford | 2 | 7 |
| Natural Bridges | 2 | 12 |
| Neola | 2 | 2 |
| Oak City | 2 | 5 |
| Park Valley | 2 | 5 |
| Portage | 2 | 22 |
| Randlett | 2 | 12 |
| Randolph | 2 | 3 |
| Scipio | 2 | 6 |
| Snowville | 2 | 13 |
| Tabiona | 2 | 12 |
| Thatcher | 2 | 13 |
| Wendover | 2 | 5 |
| Almo | 1 | 1 |
| Antimony | 1 | 1 |
| Apple Valley | 1 | 1 |
| Beryl | 1 | 1 |
| Bryce Canyon | 1 | 1 |
| Cainville | 1 | 1 |
| Christmas Meadows | 1 | 1 |
| Circleville | 1 | 1 |
| Dugway | 1 | 1 |
| Escalante | 1 | 1 |
| Fountain Green | 1 | 1 |
| Fruitland | 1 | 1 |
| Garrison | 1 | 1 |
| Greendale | 1 | 1 |
| Grouse Creek | 1 | 1 |
| Gunnison | 1 | 1 |
| Hatch | 1 | 1 |
| Kolob | 1 | 1 |
| Koosharem | 1 | 1 |
| Lapoint | 1 | 1 |
| Loa | 1 | 1 |
| Marysvale | 1 | 1 |
| Minersville | 1 | 1 |
| Moroni | 1 | 1 |
| Orderville | 1 | 1 |
| Partoun | 1 | 1 |
| Rush Valley | 1 | 1 |
| Scofield | 1 | 1 |
| Soldier Summit | 1 | 1 |
| Ticaboo | 1 | 1 |
| Timber Lakes | 1 | 1 |
| Vernon | 1 | 1 |
A rate center is the telephone exchange area a number is homed to. It sets local calling boundaries, and is not the caller's current location.
Area code 435 is a North American Numbering Plan (NANP) telephone area code assigned to Utah, United States. It is one of 3 area codes serving Utah. As population and demand for phone numbers grew, the region was divided into multiple numbering plan areas to avoid exhausting the available 7-digit number pool.
Yes. 435 is an active North American Numbering Plan (NANP) area code, currently assigned to Utah, United States. It is safe to answer or dial calls using this area code.
Area code 435 covers 111 cities and communities in Utah, including Almo, Altamont, Antimony, Apple Valley, Bear River City, and 106 more localities. This is based on telephone company rate center data — the geographic areas carriers use to determine local calling boundaries and to assign numbers when a business or individual requests a phone number in a specific city.
All numbers in the 435 area code observe Mountain Time (IANA timezone: America/Denver). Mountain Time is UTC−7 in winter (MST) and UTC−6 in summer (MDT). When placing a call to a 435 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Utah, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 435 + 7-digit number for long-distance calls within North America. From outside the US or Canada, dial your country's international exit code followed by 1 435 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 435 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +14355550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.