RADIANS(degree-angle) converts an angle from degrees to radians. It is particularly useful because Apple’s SIN and COS take radians, not degree inputs. For instance, =RADIANS(90) is approximately 1.570796.

This guide is based on Apple’s published function documentation and independently evaluated mathematical examples, not native Apple Numbers test output. Apple’s individual function documentation was consulted on 2026-10-11, using Formulas and Functions Help 15.4. That help version does not prove when the function first appeared in Numbers or whether an older iPhone, iPad, Mac or web release implements it identically. This guide deliberately separates Apple’s documented behaviour from independently calculated, mathematically expected values.

Apple defines RADIANS(degree-angle) as converting a number value from degrees to radians; customary ±360° range is advisory, not a strict limit. This is useful in calculated tables because you can retain numerical expressions instead of storing a formatted text label. For input values, choose units explicitly; an angle of 30 degrees is not the same numeric angle as 30 radians. The worked table below is intentionally small, allowing every row to be checked before applying the formula to large datasets.

=RADIANS(degree-angle)

The argument name and order above follow Apple’s official RADIANS function reference. No optional parameters were documented for this function in the reviewed edition. A numeric argument can be a typed number, numeric expression, or reference to a cell containing a number according to Apple’s value-type definitions. Do not assume the application will convert text containing units or arbitrary imported strings to valid numeric input: that behaviour was not tested here.

Locale and formula punctuation: The formulas below show English-style decimal points (0.5) and use Apple’s standard function names. Apple says functions are case-insensitive and that hand-typed multi-argument formulas use a semicolon instead of a comma when the decimal symbol is a comma. The basic RADIANS call has one argument, so its syntax does not need an argument delimiter. Nested formulas with multiple arguments still follow the user’s region. The documented rule appears in Functions overview; do not confuse it with CSV import/export delimiters.

Numbers table references: In a single table, B2 denotes B2 in that context; for another table, Numbers uses a qualified reference such as Angle Signals::B2. When typing a formula that pulls from a different table, select the intended cell and let Numbers construct the reference. Apple’s reference-type section documents the double-colon :: convention. A column name or a header may change how the editor displays an inserted reference.

Create a table called Angle Converter. Set B1 to Degrees and C1 to Radians. Enter the degree values below in B2:B8. Enter =RADIANS(B2) in C2 and fill through C8. Format C2:C8 as Number with six decimal places. This is an ordinary per-row numeric formula; it does not require an array or additional arguments.

The table shows expected, rounded mathematical results. The accompanying evidence JSON stores independently computed underlying values and formula-by-formula checks. Minor last-digit differences in displayed decimals are possible across spreadsheet engines; none of the outputs above were observed in an Apple Numbers runtime.

A quick hand-entry check

Enter =RADIANS(0) in an unused cell and check whether a numerical result appears consistent with 0.000000 when formatted to six decimals. If your application reports an error or a noticeably different value, verify the function, data type, argument units, locale and table references before proceeding.

Convert a bearing and feed it into SIN

For an angle of 30 degrees stored in B11, =SIN(RADIANS(B11)) has expected value 0.500000. Using =SIN(B11) instead treats 30 as 30 radians, which is a very different value. When the source column says degrees, wrap it in RADIANS before the trigonometric calculation.

Arc length of a circle sector

A circular arc length equals radius × central angle in radians. With radius 10 in B12 and central angle 60 degrees in C12, =B12*RADIANS(C12) yields approximately 10.471976 length units. Do not apply another factor of PI() to this formula: RADIANS already performs the π/180 conversion.

Verify the inverse conversion

=DEGREES(RADIANS(270)) is mathematically 270 degrees. Large angles, negative turns and values outside one full revolution can be converted; the function is not an angle-normalization or modulo-360 operation. A formatted result may show tiny floating-point differences for round-trips.

• Sending degrees directly to SIN or COS: SIN(30) means 30 radians, not 30°. Convert the 30 first.
• Applying PI twice: RADIANS(90)*PI()/180 performs a second conversion. Use =RADIANS(90) or =90*PI()/180, not both.
• Expecting a value between 0 and 2π: the documentation allows any numeric degree angle. For example, RADIANS(720) is approximately 12.566371; it is not reduced to zero.
• Degrees symbol in input: type a numeric value such as 90 in B2, not a text string like 90 degrees, unless a separate conversion process extracts a number.
• Unexpected decimal punctuation: a locale that uses a decimal comma displays/enters numeric decimals differently. See Apple’s formula-punctuation guidance.
• Small differences in final digits: Python and Numbers can use different floating-point evaluation/formatting; compare results at a sensible precision.

What’s verified and what isn’t: Apple’s documentation supports the function definition, its argument types and the specific documented examples. The numeric table and advanced formula results are independently calculated mathematical expectations. We did not check an app-specific error-message spelling, text-to-number coercion, huge-input floating-point limit, first-supported Numbers version, or behaviour on every device. Errors or unexpected results on very old or locale-customized installations should be investigated with the current in-app Functions Browser.

Microsoft Excel documents RADIANS(angle) for the same degrees-to-radians conversion, and its usual number results agree with the math illustrated here. No equivalence claim is made about imported text angles, error labels, locale parsing, exact precision or historical releases in Excel, Google Sheets or Numbers.

The corresponding Microsoft Excel documentation was opened at Microsoft RADIANS function on 2026-10-11. Apple and Microsoft share these familiar function spellings for the documented scalar inputs; that does not establish every edge case or feature’s version history. Google Sheets was not run and its 2026 function release coverage was not individually revalidated in this batch. Test imported models in the actual destination app rather than relying on common names alone.

• DEGREES — Apple official help (link opened and verified 2026-10-11)
• SIN — Apple official help (link opened and verified 2026-10-11)
• COS — Apple official help (link opened and verified 2026-10-11)
• PI — Apple official help (link opened and verified 2026-10-11)

The links above point directly to Apple’s official function documentation. For a companion guide on this website, use the relevant function name in the Apple Numbers directory. These links do not imply that unverified cross-software behaviour has been tested.

• Apple Numbers — function documentation
• Apple’s value-type definitions
• Functions overview
• DEGREES — Apple official help
• SIN — Apple official help
• COS — Apple official help
• PI — Apple official help

Verification status: Official documentation checked; example outcomes were independently reasoned or arithmetically checked where applicable. Not executed in Apple Numbers.

• No genuine Apple Numbers screenshots are included; this guide does not use mock application images.