The price of a campaign depends on the number of contacts selected, the length of the message, and the country you are sending to. A standard SMS is 160 chars long. If your message exceeds that limit, it will count for 2 or more SMS (depending on the length of the message).
While sending a campaign, you can see the length of the message above the "compose message" box and the estimated price on the "campaign review" page.
Note:
We also provide a "**Pricing Estimator**" on the billing page to calculate the balance you need to add to your account based on the number of messages you want to send to each country.