How many active and inactive volcanoes are there in hawaii ?

http://hvo.wr.usgs.gov/ This should be all the info you need...

There are only 2 active volcanoes and several inactive ones. Hualalai is the westernmost shield volcano on the Island of Hawaii. Three rifts radiate to the north, south, and northwest. The shield-building stage was completed by 120,000 years ago. About 105,000 years ago a trachyte cone, Puu Waawaa, formed on the north rift and generated flows that traveled about 6 miles (10 km). Post-shield volcanism began 100,000 years ago and covered the entire surface of the volcano. The most recent eruptions of Hualalai occurred in 1800-1801. Two large flows reached the ocean. The Kona airport is built on the 1801 flow. Kilauea is the youngest of the subaerial volcanoes on the Island of Hawaii and lies at the southeast end of the Hawaiian chain. Much of the bulk of the volcano is below sea level. The present-day caldera formed in 1790 A.D. and contains a pit crater, Halemaumau. Two rift zones extend to the east and southwest. Kilauea is in the shield-building stage and is one of the most active volcanoes on Earth. Over 90 percent of the surface is covered by lava less than 1,000 years old. The current eruption of Kilauea began in 1983 and is located on the East Rift Zone. Loihi is the youngest volcano associated with the Hawaiian chain and is located 15 miles (28 km) southeast of Kilauea volcano. Earthquake swarms indicate that the volcano is active. The summit of the volcano is 3,178 feet (969 m) below sea level and contains a caldera-like depression. Two rift zones extend to the north and southeast. If Loihi erupts at rates comparable to Kilauea and Mauna Loa, it will reach sea level in a few tens of thousands of years. Mauna Loa is the largest volcano on Earth with an estimated volume of 9,600 cubic miles (40,000 cubic kilometers). It makes half of the area of the Island of Hawaii. Mauna Loa began to form nearly a million years ago. There is a caldera, Mokuaweoweo, at the summit and rift zones extend to the northeast and southwest. Mauna Loa is in the shield-building stage and is one of the most active volcanoes on Earth, erupting 15 times since 1900. The last eruption was in 1984 and sent lavas within 4 miles (6.5 km) of Hilo. Mahukona (20.1N, 156.1W)is a submarine volcano on the northwest flank of the Island of Hawaii. A drowned coral reef at about 3,770 feet (-1,150 m) below sea level and a major break in slope at about 4,400 feet (-1,340 m) below sea level represent old shorelines. The summit of the volcano was once 800 feet (250 m) above sea level. It has now subsided 3,600 feet (-1100 m) below sea level. A roughly circular caldera marks the summit of Mahukona. A prominent rift zone extends to the west. A second rift zone probably extended to the east but has been buried by younger volcanoes. The main shield-building stage of volcanism ended about 470,000 years ago. The summit of the volcano subsided below sea level between 435,000 and 365,000 years ago. Kahoolawe, a single shield volcano, consists of a nearly filled caldera and a rift zone that trends to the southwest. Kahoolawe is about 12 miles (20 km) across and the smallest of the major Hawaiian Islands. Kahoolawe is made of tholeiitic and alkalic basalt of the shield and capping stages. A rock from the capping stage has been dated at about 1 million years old. During the rejuvenated stage a small number of eruptions occurred near Kanapou Bay. The age of these rocks are unknown. Kohala is the oldest of the subaerial volcanoes that make the Island Of Hawaii. Kohala is considered to be extinct because it has not erupted for 60,000 years. Deep canyons have been eroded on the north flank of the volcano. A northwest trending graben along the crest of the volcano is marked by cinder cones and domes. Mauna Kea is the tallest volcano on the Island of Hawaii. From sea floor to summit it towers more than 5.6 miles (9 km). It is also the second largest volcano on the island. It began erupting on the sea floor about 800,000 years ago. Most of the volcano is made of shield-building lavas. Post-shield volcanism began about 300,000 years ago, producing cinder cones and lava flows that cover most of the present-day surface of the volcano. The light colored material that blankets the summit of the volcano is glacial till. Mauna Kea is the only Hawaiian volcano known to be glaciated. Mauna Kea has erupted several times in the last 10,000 years. The most recent eruption was about 3,500 years ago. Mauna Kea is considered a dormant volcano. The Island of Maui is made of two volcanoes: West Maui and East Maui. Most of the West Maui shield (20.9N, 156.6W) formed between 2-1.3 million years ago. A central caldera has been identified roughly in the area of the present-day Iao Valley. Alkalic basalts capped the volcano about 1.2 million years ago. Four small eruptions occurred during the rejuvenated stage on West Maui, probably about 1 million years ago. The volcano is deeply dissected by numerous valleys. West Maui has not erupted in historic time and is considered to be extinct. East Maui Volcano, often also (but incorrectly) called Haleakala, is the easternmost of the two shield volcanoes that make the Island of Maui. East Maui Volcano (20.7N, 156.2W) is the third largest Hawaiian shield volcano. Three rift zones can be clearly seen in photographs taken from the Space Shuttle. Most of the volcanic activity has been concentrated along the southwest and east rift zones. The impressive Haleakala Crater is at the summit of the volcano. Haleakala Crater is an erosional caldera, formed by the coalescence of the heads of two large valleys as they eroded into the volcano. The main shield of Haleakala is more than 800,000 years old. Lava flows and pyroclastics of the capping stage range in age from 930,000 to 350,000 years old. Rejuvenated-stage volcanic rocks occur along the rift zones and in the crater. The most recent eruption of Haleakala was in about 1790 at La Perouse Bay. Haleakala is considered an active volcano because this eruption is in historic time for Hawaii. Kahoolawe (20.5N, 156.6W) is one of the smallest shield volcanoes in the Hawaiian Islands. Kahoolawe is the island near the bottom of the slide. The lava flows that make the main shield are 1-2 million years old. Wave erosion has exposed a caldera on the eastside of the island. Kahoolawe has not erupted in historic time and is considered to be extinct. The island of Oahu is made of two volcanoes: Waianae and Koolau (map). Waianae, the older of the two volcanoes, (21.4N, 158.2W) makes up the west part of the island. The shield of Waianae volcano formed between 3.8 and 2.95 million years ago. A caldera is located near the center of the Waianae Range and rift zones extend to the northwest and southeast. Lava flows of the capping-stage are about 1.8 million years ago. Rocks from the renewed volcanism stage are also present but have not been dated. This volcano has been extensively modified by erosion. Koolau is a large basaltic volcano that makes the east side of the island. The main shield is about 2.7 to 1.8 million years old. A caldera is located just south of Kaneohe Bay, the prominent bay on the north side of the island. Numerous dikes mark the location of a rift zone that trends to the northwest. About half a mile (1 km) of the volcano was eroded to expose these dikes. No rocks from the capping stage have been found on Koolau volcano. Some of Hawaii's most famous landmarks (e.g., Diamond Head, Hanauma Bay, and Koko Crater), are tuff rings and cinder and spatter cones from the renewed volcanism stage. These features formed between one million and, possibly, 10,000 years ago. Much of Koolau volcano was also removed by a giant landslide .

There is only one on the Island of Hawaii (a.k.a. The Big Island) Kilauea.