---
title: ConverterBase (v0.46)
description: API reference for qiskit.opflow.converters.ConverterBase in qiskit v0.46
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/0.46/qiskit.opflow.converters.ConverterBase
---

# ConverterBase

*class* `qiskit.opflow.converters.ConverterBase`

[GitHub](https://github.com/qiskit/qiskit/tree/stable/0.46/qiskit/opflow/converters/converter_base.py)

Bases: [`ABC`](https://docs.python.org/3/library/abc.html#abc.ABC)

Deprecated: Converters take an Operator and return a new Operator, generally isomorphic in some way with the first, but with certain desired properties. For example, a converter may accept `CircuitOp` and return a `SummedOp` of `PauliOps` representing the circuit unitary. Converters may not have polynomial space or time scaling in their operations. On the contrary, many converters, such as a `MatrixExpectation` or `MatrixEvolution`, which convert `PauliOps` to `MatrixOps` internally, will require time or space exponential in the number of qubits unless a clever trick is known (such as the use of sparse matrices).

> **Deprecated since version 0.24.0**
>
> The class `qiskit.opflow.converters.converter_base.ConverterBase` is deprecated as of qiskit-terra 0.24.0. It will be removed in the Qiskit 1.0 release. For code migration guidelines, visit [https://qisk.it/opflow\_migration](https://qisk.it/opflow_migration).

## Methods

### convert

*abstract* `convert(operator)`

Accept the Operator and return the converted Operator

**Parameters**

**operator** ([*OperatorBase*](/docs/api/qiskit/0.46/qiskit.opflow.OperatorBase "qiskit.opflow.operator_base.OperatorBase")) – The Operator to convert.

**Returns**

The converted Operator.

**Return type**

[*OperatorBase*](/docs/api/qiskit/0.46/qiskit.opflow.OperatorBase "qiskit.opflow.operator_base.OperatorBase")