> ## Documentation Index
> Fetch the complete documentation index at: https://plivo.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Billing Concepts

> How billing works for voice calls, SMS, MMS, and phone numbers on Plivo

Frequently asked questions about how Plivo charges for voice calls, messaging, and phone numbers.

***

## How does voice call billing work?

Plivo bills voice calls based on per-minute rates with billing increments that depend on the product:

| Product                 | Billing Increment | How It Works                                                                                                                     |
| ----------------------- | ----------------- | -------------------------------------------------------------------------------------------------------------------------------- |
| Voice API               | 60-second (60/60) | Calls are rounded up to the next full minute. A 10-second call is billed as 1 minute.                                            |
| Zentrunk (SIP Trunking) | Varies by country | Per-second (1/1) for US routes, 60-second (60/60) for India routes. Other destinations vary — check your rate sheet for details. |

**Key details:**

* Billing starts when the call is answered, not when it starts ringing.
* Both inbound and outbound call legs are billed separately.
* Rates vary by destination country and number type. See [Voice Pricing](https://www.plivo.com/pricing/voice/) for current rates.

***

## How does SMS and MMS billing work?

SMS and MMS are billed **per message segment**.

**SMS segments:**

* A single SMS segment can contain up to **160 characters** using GSM-7 encoding (standard Latin characters).
* If your message uses **Unicode** characters (such as non-Latin scripts or special symbols), the segment limit drops to **70 characters**.
* Messages longer than one segment are split into multiple segments, each billed separately. For multi-part messages, segment limits are 153 characters (GSM-7) or 67 characters (Unicode) due to concatenation headers.

**MMS:**

* MMS messages are billed per message, regardless of media size.
* MMS is available only for US and Canadian destinations.

See [SMS Pricing](https://www.plivo.com/pricing/sms/) for current per-segment rates.

***

## What are phone number charges?

Plivo charges a **monthly rental fee** for each phone number on your account.

* Rental is charged on a calendar-month basis starting from the date of purchase.
* Rates vary by country and number type (local, toll-free, mobile, national).
* Some countries may have one-time setup charges in addition to the monthly rental.
* Numbers removed mid-month are billed for the full month.

See [Phone Number Pricing](https://www.plivo.com/virtual-phone-numbers/pricing/) for rates by country.

***

## What is CPS and how do I increase it?

**CPS (Calls Per Second)** is the maximum number of concurrent outbound call requests Plivo processes per second for your account.

| Account Type | Default CPS                      |
| ------------ | -------------------------------- |
| Standard     | 2 CPS                            |
| Enterprise   | Custom (higher limits available) |

Voice API and Zentrunk (SIP Trunking) each have their own separate CPS limit per account. For example, a standard account can initiate 2 outbound calls per second via Voice API and 2 outbound calls per second via Zentrunk simultaneously.

If you need higher CPS for large-scale calling campaigns or high-volume applications, contact [Plivo Sales](https://www.plivo.com/contact-sales/) to discuss an Enterprise plan with increased CPS limits.

<Note>
  CPS limits apply to outbound call initiation only. They do not limit the number of concurrent active calls on your account.
</Note>

***

## What do billing increments like 1/1 and 6/6 mean?

These are standard telecom billing increment notations in the format **initial/subsequent**:

| Increment | Meaning                                                                                                |
| --------- | ------------------------------------------------------------------------------------------------------ |
| **1/1**   | Per-second billing — both the first and every subsequent second are billed individually                |
| **6/6**   | Billed in 6-second blocks — the first 6 seconds are billed as a block, then every additional 6 seconds |
| **60/60** | Per-minute billing — the first 60 seconds are billed as a block, then every additional 60 seconds      |
| **30/6**  | First 30 seconds billed as a block, then every additional 6 seconds                                    |

**Example with 60/60 billing:** A call lasting 61 seconds is billed as 120 seconds (2 minutes).

Plivo Voice API uses **60/60** (per-minute) billing. Zentrunk billing increments vary by country — for example, **1/1** (per-second) for US routes and **60/60** (per-minute) for India routes. Check your Zentrunk rate sheet for destination-specific increments.

***

## Related Resources

* [Payments](/faq/billing-and-invoices/payments)
* [Invoices](/faq/billing-and-invoices/invoices)
* [Taxes](/faq/billing-and-invoices/taxes)
* [Voice Pricing](https://www.plivo.com/pricing/voice/)
* [SMS Pricing](https://www.plivo.com/pricing/sms/)
* [Phone Number Pricing](https://www.plivo.com/virtual-phone-numbers/pricing/)