SIN function

SIN returns the sine of an angle in radians, a decimal value between -1 and 1 representing the trigonometric sine ratio.

=SIN(number)

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How to get a better answer
  • Name your columns by letter and by header: "column F (Net Value)" beats "the amount column".
  • State every condition, including the negatives — "not cancelled" changes the formula's shape.
  • Say where the data starts if it is not row 1, and whether it will grow.
  • Check the settings above match your spreadsheet: the wrong argument separator is a syntax error on your machine.

Arguments

How SIN reads its arguments
numberrequiredSIN →
ArgumentRequiredDescription
numberRequiredRequired. The angle in radians for which to calculate the sine. Accepts any real number; SIN is defined for all inputs.

Returns

A decimal number between -1 and 1.

Availability

Excel: All · Google Sheets: Supported

Worked examples

1. Create seasonal budget adjustment factors by month

CategoryMonthBudgetedActualVariance
UtilitiesJanuary1501455
UtilitiesApril150162-12
UtilitiesJuly150175-25
UtilitiesOctober150158-8
=ROUND(SIN(RADIANS(ROW()*30)), 3)

Result: 0.5, 0.866, 1.0, 0.866 (multipliers cycling through seasons)

SIN maps month positions (1, 4, 7, 10) to angles (30°, 120°, 210°, 300°), producing a wave that peaks midsummer. This models how utility costs oscillate seasonally without manually entering each month's adjustment.

2. Normalize variance into a periodic pattern score

CategoryMonthBudgetedActualVariance
GroceriesJan400420-20
GroceriesFeb400410-10
GroceriesMar4003955
GroceriesApr400405-5
=ROUND(ABS(SIN(RADIANS(COLUMN()*45))), 2)

Result: 0.71, 1.0, 0.71, 0 (pattern intensity by quarter)

Takes the absolute sine value at 45° increments (columns represent quarters), creating a score from 0–1. High values indicate quarters where spending variance is most pronounced; low values identify flat periods. Useful for detecting whether variances follow a predictable rhythm.

3. Smooth expense ratios into a wave-based forecast model

CategoryMonthBudgetedActualVariance
TransportMonth1200210-10
TransportMonth2200215-15
TransportMonth52002000
TransportMonth10200205-5
=ROUND(1.2 + 0.3*SIN(RADIANS(ROW()*36)), 2)

Result: 1.36, 1.46, 1.20, 1.05 (cyclical multipliers)

Scales SIN output (–1 to 1) by ±0.3 and offsets by 1.2, producing budget multipliers that cycle between 0.9 and 1.5. This model forecasts that transport costs oscillate over a 10-month period, enabling proactive budget planning without assuming flat spending.

Common errors

Which SIN error are you seeing?
SIN returned an error#VALUE!
Convert text to a number using VALUE(): =SIN(RADIANS(VALUE(A1))). Or ensure the cell contains only a number, not a label.
#NAME?
Correct the function name to exactly =SIN(number) with matching parentheses. Verify no extra spaces or typographical errors.
#VALUE!
Use a single cell reference: =SIN(A1). To process a range, use BYROW or BYCOL in newer versions, or apply SIN to individual rows.
ErrorWhy it happensHow to fix it
#VALUE!SIN receives text or a cell containing non-numeric text, such as =SIN("45") or =SIN(A1) where A1 contains "January".Convert text to a number using VALUE(): =SIN(RADIANS(VALUE(A1))). Or ensure the cell contains only a number, not a label.
#NAME?The function name is misspelled or unrecognized, such as =SINE(45), =SIN45, or =Sin (case sensitivity issues in some contexts).Correct the function name to exactly =SIN(number) with matching parentheses. Verify no extra spaces or typographical errors.
#VALUE!SIN is applied to a range instead of a single value, such as =SIN(A1:A10), or to a cell containing a formula that returns an error.Use a single cell reference: =SIN(A1). To process a range, use BYROW or BYCOL in newer versions, or apply SIN to individual rows.

Tips and when to use something else

  • SIN expects radians, not degrees. If your data is in degrees, use =SIN(RADIANS(90)) which returns 1.0, not 0.0157.
  • SIN output is always between −1 and 1. To shift and scale, try =0.5 + SIN(x)/2 for a range of 0–1, or =1 + SIN(x) for 0–2.
  • For aggregating budget data (summing categories, filtering by month), use SUM or SUMIF instead of SIN—they're designed for totaling, not mathematics.
  • SIN is useful for modeling cyclical patterns (seasonal expenses, repeating schedules), but not for financial calculations like interest or amortization; use PMT or SUMPRODUCT for those.

Related functions

ABSABS returns the absolute value of any number, removing the sign to show only magnitude, useful for comparing distances regardless of direction.ROUNDROUND returns a number rounded to a specified number of decimal places, using standard rounding rules (0.5 rounds up).IFThe IF function returns one value if a condition is true and another (or nothing) if it is false, letting you branch logic in a cell.MROUNDMROUND rounds a number to the nearest multiple of a specified value, useful for rounding to standard increments like 5, 10, or 100.

Frequently asked questions

Why does =SIN(45) give 0.8509 instead of 1?
Because SIN interprets 45 as 45 radians (≈2,578°), not 45 degrees. To calculate the sine of 45°, use =SIN(RADIANS(45)), which returns ≈0.707. Radians are the standard angle unit in spreadsheets; 1 radian ≈ 57.3°, and 2π radians = 360°.
What's the relationship between SIN and other trigonometric functions?
SIN calculates sine; related functions include COS (cosine) and TAN (tangent). To reverse SIN and recover the original angle, use ASIN (arcsine), though ASIN only returns values between −π/2 and π/2 radians. These are pure mathematical functions, not available in the 'related' list but often used together.
Can I use SIN to model expense trends in a budget?
Yes, if expenses follow a predictable cyclical pattern (e.g., seasonal utility costs or monthly transportation spikes). Wrap SIN in ROUND and scale it to your expected range. However, if your actual data doesn't follow a sine wave, your model will diverge; in that case, use AVERAGE, FORECAST, or SUMIF to analyze actual trends instead.
How do I use SIN output in conditional logic?
Nest SIN inside IF or IFS. For example, =IF(SIN(RADIANS(A1))>0.5, "High", "Low") flags months where the sine value exceeds 0.5. This pairs well with budget variance analysis to highlight periods of expected high volatility.

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Reviewed 2026-09-17