gridcraft/docs/function-parity.md

Function parity: worksheet functions and formulas

Last reviewed: 2026-10-31 · Last updated: 2026-10-31 · Change: minor (HARMEAN returns #N/A when its arguments contain no numeric observations; earlier: BETA.DIST density returns #NUM! when an endpoint's corresponding shape parameter is less than or equal to 1; earlier: ECMA.CEILING listed with USDOLLAR as not on Microsoft's list; earlier: IMSQRT reproduces the stray real part Excel gives for negative reals, and the other IM* differences from Excel are listed) · Target: Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4

Excel's worksheet functions, category by category, against GridCraft's function library. Part of target-app-parity.md; gaps feed gaps.md.

How this is measured

• Excel's list (523): Microsoft's "Excel functions (alphabetical)" support page, fetched and parsed on 2026-10-10 (506 rows with their category and the Excel version that introduced them), plus 14 text functions the page lists under combined entries (FIND/FINDB, LEFT/LEFTB, LEN/LENB, MID/MIDB, REPLACE/REPLACEB, RIGHT/RIGHTB, SEARCH/SEARCHB), BETA.INV, and COPILOT and PY (Microsoft 365 functions not on that page when fetched).
• Ours (505): every function spec in crates/functions/src/*.rs (f!("NAME", …)) plus the
• Ours (503): every function spec in crates/functions/src/*.rs (f!("NAME", …)) plus the
• Ours (502): every function spec in crates/functions/src/*.rs (f!("NAME", …)) plus the
• Ours (502): every function spec in crates/functions/src/*.rs (f!("NAME", …)) plus the
• Ours (505): every function spec in crates/functions/src/*.rs (f!("NAME", …)) plus the evaluator's special forms in crates/calc/src/eval.rs (SPECIAL_FUNCTIONS: IF, IFS, CHOOSE, OFFSET, INDIRECT, INDEX, SUBTOTAL, AGGREGATE, TEXT, LET, LAMBDA, MAP, REDUCE, SCAN, BYROW, BYCOL, MAKEARRAY…), excluding the test-only ADD2. Every one is an Excel name.
• Not on Microsoft's list: USDOLLAR and ECMA.CEILING, legacy functions Excel still evaluates (like DOLLAR), are in our library as Compatibility functions for files that use them. They are not counted above.
• Working excludes stubs that return an error by design: the 7 CUBE functions (#N/A, no cube connections) and WEBSERVICE and FILTERXML (#VALUE!). Excel for Mac also lacks WEBSERVICE and FILTERXML; Excel for Windows has them.
• The measurement is presence. Depth (edge cases matching Excel) is estimated below.

Coverage

Measured: 513 / 523 by name (98.1%); 504 / 523 working (96.4%).

Category	Excel	Ours	Working	% working	Missing
Statistical	111	111	111	100%	—
Math and trigonometry	80	79	79	99%	PERCENTOF
Financial	55	55	55	100%	—
Engineering	54	54	54	100%	—
Text	50	48	48	96%	DETECTLANGUAGE, TRANSLATE
Lookup and reference	40	36	36	90%	GETPIVOTDATA, IMAGE, RTD, TRIMRANGE
Compatibility	40	40	40	100%	—
Date and time	25	25	25	100%	—
Information	22	21	21	95%	STOCKHISTORY
Logical	19	19	19	100%	—
Database	12	12	12	100%	—
Cube	7	7	0	0%	(all 7 are #N/A stubs)
Web	3	3	1	33%	(WEBSERVICE, FILTERXML are stubs; ENCODEURL works)
Add-in and Automation	3	1	1	33%	CALL, REGISTER.ID
AI and Python	2	0	0	0%	COPILOT, PY
Total	523	505	496	94.8%	18 missing, 9 stubs

By the Excel version that introduced them (working / total): before 2010 346 / 360, 2010 56 / 56, 2013 49 / 51, 2016 1 / 5, 2019 6 / 6, 2021 11 / 11, 2024 22 / 23, Microsoft 365 5 / 11. Dynamic-array and LAMBDA-era functions (FILTER, SORT, UNIQUE, XLOOKUP, VSTACK, TAKE, GROUPBY, PIVOTBY, REGEXTEST…) are all present.

FORECAST.ETS missing-point interpolation walks known points once, so filling a long gap takes linear work in the completed timeline length (#1042). Interpolation values, nearest-value endpoint handling, zero-fill mode and the existing 30% missing-point limit are unchanged. This improves series preparation; it does not change the model-fitting or seasonality algorithms.

Scope of what's missing

Function(s)	In scope?	Estimate	Note
FORECAST.ETS family (4)	yes	4–6 h	AAA exponential smoothing with seasonality detection; needed for Forecast Sheet too
ODDFPRICE, ODDFYIELD, ODDLPRICE, ODDLYIELD	yes	2–4 h	Odd first/last period bond maths
GETPIVOTDATA	yes	2–3 h	Needs the pivot engine's result cache; also the "Generate GetPivotData" option
IMAGE	yes	3–5 h	Pictures in cells (see PR #105); fetching URLs needs a privacy decision
CUBE* (7), WEBSERVICE, FILTERXML	partly	4–8 h	FILTERXML can work offline; CUBE needs an OLAP/data-model source
TRANSLATE, DETECTLANGUAGE, STOCKHISTORY, COPILOT, PY	no (cloud)	—	Microsoft cloud services; open equivalents only by owner decision
CALL, REGISTER.ID, RTD	no	—	Native DLL/COM calls; not portable or safe

Formula language

Feature	Status
A1 and R1C1 references, absolute/relative/mixed, F4 cycling	done
3-D references (Sheet1:Sheet3!A1)	done; deleting a span's end sheet keeps the rest (#140)
Structured references (Table1[Col], [#Totals], @; the unbracketed [[#This Row],Col] some writers emit)	done
Defined names (workbook and sheet scope), Create from Selection	done
Dynamic arrays, spill, #SPILL!, spill operator A1#	done; stale spills after a structural edit or a cleared blocker fixed (#133, #139; PRs #148, #157)
Recalculation after clearing large sparse ranges	every stored cell changed by Clear is reported to recalculation, without a million-coordinate cutoff; removed formula spills are cleared, and removing empty merges still unblocks spills (#1032)
SUBTOTAL / AGGREGATE input size	references trim to the used range; all areas, arrays and values of one call are charged against the 16-million-cell limit before any cell is read (skipped hidden, nested and error cells count), and #NUM! past it (#2175)
Implicit intersection @, legacy CSE array formulas	done; legacy array range fill (PR #156)
Implicit intersection @, legacy CSE array formulas	done, the entered range filled (PR #156)
Array lifting: an array in a scalar argument evaluates the function per element	done. The Analysis ToolPak functions (EOMONTH, EDATE, WORKDAY(.INTL), NETWORKDAYS(.INTL), YEARFRAC, WEEKNUM, the COUP*, PRICE*, YIELD*, ODD*, TBILL*, ACCRINT*, AMOR*, DISC, DURATION, CUMIPMT/CUMPRINC, EFFECT, NOMINAL, DOLLARDE/FR, XNPV/XIRR rate and guess, FVSCHEDULE principal, ISEVEN/ISODD, QUOTIENT, MROUND, FACTDOUBLE, SQRTPI, RANDBETWEEN, SERIESSUM, the base conversions, CONVERT, DELTA, GESTEP, ERF/ERFC, BESSEL*, COMPLEX and IM* except IMSUM/IMPRODUCT) give #VALUE! for a reference to more than one cell in a value argument, as Excel 365 does in both dynamic-array and legacy formulas; array constants and computed arrays (A1:A3+0) still lift, and range arguments (holidays, schedule, cash flows) and the .INTL weekend accept ranges. Difference: BYROW/BYCOL pass their row or column to the LAMBDA as values, so BYROW(A1:B3,LAMBDA(r,EOMONTH(r,0))) lifts where Excel gives #VALUE!
Trim references A1:.E10 (trailing), A1.:E10 (leading), A1.:.E10 (both), also on whole rows/columns (A:.A)	done; evaluated as TRIMRANGE(range, code, code), adjusted on insert/delete; files store _xlfn.TRIMRANGE(range,code,code) (Excel's own file spelling unconfirmed in public docs), _xlfn._TRO_ALL/_TRO_LEADING/_TRO_TRAILING(...) read too
LET, LAMBDA, named LAMBDAs, ISOMITTED, MAP/REDUCE/SCAN/BYROW/BYCOL/MAKEARRAY	done. A LAMBDA that calls itself more than 140 times, or a formula nested past the depth limit, gives #NUM! (the target app allows deeper recursion, #1581). Calling a defined name that holds an error value gives that error, not #NAME?
Iterative calculation for circular references	done: with Enable Iterative Calculation on (formulas.calculationOptions {iterative, maxIterations, maxChange}, saved as <calcPr iterate iterateCount iterateDelta>), loops are evaluated again from their previous values (blank = 0) until no cell on a loop changes by Maximum Change or Maximum Iterations is reached; off, cycles give #CIRC!. Set in File › Options › Formulas (Enable iterative calculation, Maximum Iterations 1 to 32767, Maximum Change 0 or more; the two fields are disabled while iteration is off). Differences: GridCraft recalculates on open, so a loop that never settles (=A1+1) advances again each time the file is opened
15-significant-digit comparison semantics	done (#57): =0.1+0.2=0.3 is TRUE, and MATCH and COUNTIF compare the same way. Arithmetic keeps full precision, as Excel does — =(0.1+0.2)-0.3 is 5.55E-17
IMSQRT and the other IM* functions against Excel's text	IMSQRT follows Excel's polar route, so a negative real gives Excel's stray real part: IMSQRT("-4") is 1.22514845490862E-16+2i (checked in Excel 16.0 on 79 inputs). Differences kept: IMSQRT of a number with a part above about 1E154 or below about 1E-155 gives the exact root (Excel gives #NUM! or 0); IMPOWER, IMEXP, IMSIN, IMCOS, IMSINH and IMCOSH keep exact results where Excel shows the same kind of noise (IMPOWER("-4",2) is 16-3.92047505570758E-15i) or different trailing digits near multiples of pi/2; IMCSC and IMCSCH differ by one unit in the 15th digit; IMARGUMENT returns 16–17 digits where Excel returns 15; the text of IM* and COMPLEX results differs for some magnitudes (Excel writes COMPLEX(1E-10,1) as 0.0000000001+i but COMPLEX(0.000000123456789012345,1) as 1.23456789012345E-07+i, and an integer past 15 digits rounded and zero-padded)
External workbook references ([Book.xlsx]Sheet1!A1)	parsed; links dropped on open, no update
Localized function names and ; separators	missing (#45); en-US only
Long flat operator chains (=A1+A2+…, -, *, /, ^, &, comparisons)	done: no operand limit below Excel's 8,192-character formula limit (Excel, observed: =1+1+… with 4,096 operands is exactly 8,192 characters with the = and calculates; one more character is refused). Evaluated (#484), printed (#628), stored, copied, adjusted, saved and reopened without recursing once per operand, on a 1 MiB stack (#916); written to XLSX as plain formulas, not dynamic arrays; Spanish entry accepts them
Error values	the seven classic errors plus #SPILL!, #CALC!, #GETTING_DATA done; #FIELD!, #BLOCKED!, #CONNECT!, #BUSY!, #UNKNOWN!, #PYTHON! missing (minor: they come from data types, cloud and Python features)

Depth (estimated)

Function	Excel parity note
BINOM.DIST / BINOM.DIST.RANGE	Trial count is truncated, then must be at most 2,147,483,646; larger trials return #NUM!.

| BETA.DIST | Density mode returns #NUM! at the lower or upper interval endpoint when the corresponding shape parameter is less than or equal to 1; cumulative endpoint results remain 0 and 1. | | HARMEAN | Returns #N/A when arrays and references contain no numeric observations; zero and negative numeric observations still return #NUM!. | ~82% ready. The library is broad and has 96 test functions in crates/functions with many assertions each, but there is no conformance suite against Excel-computed results, and user reports keep finding edge cases: MIN() with no arguments (#138), COUNTBLANK past the used range (#137, and past 16,384 cells #1010, fixed 10-14 for bounded references), ROUND at 15 digits and DATE(1900,2,29) (fixed 10-09), SUMIF sum-range sizing (fixed 10-09). Statistical distributions and financial functions with iterative solvers (RATE, IRR, XIRR, YIELD) are the highest-risk for last-digit differences.

TEXT() and cell display share crates/numfmt; checked against Excel-cached results in number- and text-format test workbooks (352 TEXT cells), all match: fraction sections with literal text (#\:#=/=#, #_#/#), zero fractions, zero-padded denominators, ? placeholders padding the thousands separator, and booleans through the text section (TEXT(TRUE,";;;\@@\@") = @TRUE@).

MEDIAN and AGGREGATE function number 12 use an overflow-safe midpoint for even-sized inputs, so large finite middle values do not become #NUM! merely because their sum overflows (#1579). Sorting, argument coercion and error propagation are unchanged; this is a numerical correction under the documented median rule, not an extreme-value comparison against desktop Excel.

Work to close (16–26 h in total): the in-scope missing functions (10–16 h with the table above), an oracle corpus of Excel-computed results per function (owner runs Excel on generated workbooks; results checked in as data, not Excel files) and fixing what it finds (6–10 h).

Revision history

Date	Change	Summary
2026-10-31	minor	BIN2*, HEX2* and OCT2* reject surrounding spaces and tabs in source strings with #NUM!, matching Excel; plain unpadded values remain valid
2026-10-31	minor	DEC2BIN, DEC2HEX and DEC2OCT validate places before returning negative two's-complement output, and Boolean places return #VALUE!, matching Excel
2026-10-31	minor	BITLSHIFT and BITRSHIFT return 0 for zero operands shifted beyond 53 bits in either direction; nonzero operands retain the #NUM! limit, matching Excel
2026-10-31	minor	UNICHAR returns #N/A for U+FDD0–U+FDEF and U+FFFE/U+FFFF on every plane; adjacent valid characters and existing invalid-range/surrogate errors remain unchanged, matching Excel
2026-10-31	minor	UPPER, LOWER and PROPER use single-character casing: UPPER("Straße") keeps ß, LOWER("İ") returns i, and PROPER("İSTANBUL") returns Istanbul, matching Windows Excel 16.0 build 20527 in LCID 1033
2026-10-31	minor	FIXED and DOLLAR format the rounded number's shortest decimal representation before padding requested fractional zeroes, so 1.1 at 16 places and 1.005 at 20 places do not expose binary noise; measured in Windows Excel 16.0 build 20527, LCID 1033
2026-10-31	minor	FIXED accepts output through 255 characters; DOLLAR accepts output through 254. Windows Excel 16.0 build 20527 (LCID 1033) confirmed the distinct cutoffs with grouped and ungrouped values, signs, currency layout and decimal places
2026-10-31	minor	DOLLAR uses the input sign for negative amounts that round to zero at nonnegative decimal places (DOLLAR(-0.0001,0) is ($0)); when negative decimal places round to zero, Excel returns $0. Exact zero and negative zero stay unsigned; FIXED still returns 0 for FIXED(-0.0001,0)
2026-10-31	minor	F.DIST, F.DIST.RT, F.INV and F.INV.RT accept degrees of freedom at the 10-billion boundary; F.INV uses the complementary tail, with a gamma-tail limit when numerator degrees dominate, to preserve inverse accuracy; values above the limit remain invalid
2026-10-31	minor	T.DIST returns #DIV/0! in density mode and #NUM! in cumulative mode when degrees truncate to zero; negative integer degrees remain #NUM!
2026-10-31	minor	Student-t density uses an asymptotic log-gamma ratio for large degrees of freedom, avoiding cancellation while preserving bounded work; checked against Excel at 100 million and 10 billion degrees
2026-10-31	minor	T.INV probability zero returns #DIV/0!, while other out-of-range probabilities and invalid degrees remain #NUM!; T.INV.2T keeps its separate boundary behavior
2026-10-31	minor	GAMMA.DIST density at x=0 and shape 1 returns #NUM! for all positive scales; the cumulative branch and other shape boundaries are unchanged
2026-10-31	minor	WEIBULL.DIST returns zero at x=0 in both density and cumulative modes, including shape below one; negative x remains #NUM!
2026-10-31	minor	BINOM.DIST and BINOM.DIST.RANGE reject trial counts above 2,147,483,646 after truncation
2026-10-31	minor	BETA.DIST density returns #NUM! at the lower endpoint with alpha less than or equal to 1 and upper endpoint with beta less than or equal to 1; cumulative behavior is unchanged
2026-10-31	minor	HARMEAN returns #N/A when array or reference inputs contain no numbers; nonpositive numeric observations remain #NUM!
2026-10-27	minor	ECMA.CEILING added to the functions that are in our library but not on Microsoft's list (with USDOLLAR), so the counts don't change
2026-10-26	minor	IMSQRT uses Excel's polar route with its cosine reduction, so IMSQRT("-4") is 1.22514845490862E-16+2i as in Excel (exact 2i before); the rows list the IM* differences still open
2026-10-25	minor	LAMBDA row: a LAMBDA that calls itself more than 140 times, and a formula nested past the depth limit, give #NUM! (#1809; nesting gave #CALC! before). =Foo(1) where the defined name Foo holds #N/A gives #N/A, not #NAME?
2026-10-23	minor	Number text coercion (VALUE, arithmetic, typed entry): a dollar sign before accounting parentheses ($(1,234), $ (5)) and a percent sign after them ((5)%) read as negatives; (-5), ((5)), ($-5), $5%, $(5)% and dates or times in parentheses are #VALUE!, as observed in Excel 365
2026-10-23	minor	INDEX with only a row index on a reference of several rows and columns (INDEX(A1:C3,2), INDEX(A1:C3,0)) is #REF!, as observed in Excel, so it also fails as a range endpoint and inside other functions; an empty column argument (INDEX(A1:C3,2,)) still gives the row. Checked that a column array with one index stays a 1×1 array (TYPE 64), which is what Excel returns
2026-10-21	minor	SUBTOTAL and AGGREGATE charge every argument against the evaluator's 16-million-cell limit before scanning; a value in XFD1048576 no longer makes SUBTOTAL(9,A:XFD) read the whole sheet (#2175)
2026-10-19	minor	LET and LAMBDA names compare case-insensitively in any script, as in Excel: =LET(dług,100,DŁUG*2) is 200 (was #NAME?); also LET-bound lambdas called or passed by name (żar(2), MAP(…,Λ)), ISOMITTED, and formula-bar alias translation (one shared gridcraft_formula::same_name, which matches ß with ẞ and keeps dotless ı apart from i)
2026-10-19	minor	Long flat operator chains (#916): 4,096 operands (Excel's 8,192-character limit) no longer overflow the stack when entered, filled, adjusted or saved; chains past 64 operands are no longer saved as dynamic-array formulas; Spanish entry no longer refuses chains past 256 operands
2026-10-17	minor	15-significant-digit comparison moved from missing to done (#57), and the resolved caveats on the 3-D reference, dynamic-array and legacy-array rows cleared (#140, #133, #139, #156)
2026-10-16	minor	FORECAST.ETS gap interpolation uses a forward-only known-point scan instead of rescanning each gap for every missing value; numerical behavior and missing-point limits are preserved (#1042)
2026-10-15	minor	Iterative calculation: Maximum Iterations and Maximum Change are set in File › Options › Formulas (dropped "no Options dialog yet")
2026-10-15	minor	MEDIAN and AGGREGATE median use an overflow-safe midpoint (#1579); regressions cover finite extremes, tiny values and dependent recalculation
2026-10-15	minor	ADDRESS quotes a sheet name the way Excel does: names that read as an A1 cell (A1) or an R1C1 reference (R1C1, RC) and names starting with . get quotes; TRUE / FALSE stay bare (#1458)
2026-10-14	minor	MATCH, XMATCH, VLOOKUP, HLOOKUP, XLOOKUP and LOOKUP compare numbers exactly in every match and search mode, as Excel 365 does: MATCH(0.1+0.2,{0.3},0) is #N/A and 0.3 sorts below 0.30000000000000004 in approximate and binary search. =, SWITCH and the criteria functions (COUNTIF(S), SUMIF(S), AVERAGEIF(S), MAXIFS…) keep comparing at 15 significant digits, also as observed
2026-10-14	minor	Analysis ToolPak value arguments (EOMONTH, WORKDAY, YEARFRAC, COUPDAYS, DISC, BIN2DEC, IM* and the rest, observed in Excel 365) give #VALUE! for a multi-cell reference instead of lifting it
2026-10-13	minor	Clear reports changed stored cells sparsely, including those beyond the first million coordinates; dependent formulas and removed spills update, while clearing empty merges still unblocks spills (#1032)
2026-10-14	minor	Bounded references up to 1,048,576 cells (D3:AZ400) keep their full shape instead of stopping at the used range, so SUMPRODUCT(D3:AZ400*B3:B400,(A3:A400=x)*(D1:AZ1=y)) broadcasts like Excel and ROWS, COUNTBLANK and --(r="") count the blanks; references that run to the edge of the sheet (A:A) still stop at the used range (#1010)
2026-10-12	minor	USDOLLAR added as a Compatibility function (not on Microsoft's list, so the counts don't change); MIRR with no positive flow is -1, COUNTIF's bare "<=" / ">=" skip empty strings, INDIRECT with a1 = FALSE gives #REF! for A1-style text (#738)
2026-10-11	minor	TEXT / number formats fixed against Excel-cached results: fraction literals and zero fractions, 0 denominators zero padded, ? pads the thousands separator, booleans use the text section (226 mismatches → 0 in 352 TEXT cells)
2026-10-11	minor	Iterative calculation: circular references iterate up to Maximum Iterations / Maximum Change when enabled
2026-10-11	minor	Trim-reference operators (:., .:, .:.) and unbracketed [[#This Row],Col] done; dropped the stale "Scope of what's missing" rows for TRIMRANGE, PERCENTOF, BAHTTEXT and the trim references
2026-10-11	minor	Fixes from the cached-value oracle (gridcraft-cli check): MODE / MODE.SNGL / MODE.MULT give #VALUE! for text in a direct argument or single-cell reference; VALUE("") is #VALUE!; SUMPRODUCT with a text scalar argument is #VALUE!; ADDRESS leaves [Book]Sheet unquoted; VLOOKUP / HLOOKUP / LOOKUP / MATCH approximate match bisect like Excel on unsorted mixed-type data; XLOOKUP / XMATCH binary search compares across types in sort order; SUBTOTAL leaves out filtered rows for every function number (table and sheet AutoFilters)
2026-10-11	minor	ODDFPRICE, ODDFYIELD, ODDLPRICE, ODDLYIELD added: Financial 55 / 55; 505 / 523 by name, 496 working
2026-10-11	minor	PERCENTOF and EUROCONVERT added: 503 / 523 by name, 494 working
2026-10-11	minor	BAHTTEXT added: 502 / 523 by name, 493 working
2026-10-11	minor	TRIMRANGE added (the trim-reference operators not yet): 502 / 523 by name, 493 working
2026-10-11	minor	FORECAST.ETS, .CONFINT, .SEASONALITY, .STAT added (AAA exponential smoothing; Excel's optimiser is undocumented, so last digits on noisy data may differ): 505 / 523 by name, 496 working
2026-10-10	major	Created: 501 / 523 by name, 492 working, per category, against Microsoft's published list