# SheetAtlas (https://sheetatlas.com)

> SheetAtlas is an authoritative repository of free, formula-driven Microsoft Excel (.xlsx) spreadsheets, construction takeoff calculators, NEC electrical panel schedules, and CPA audit workpapers with live client-side interactive previews.

## Core Spreadsheet Silos
- [Construction Estimating & Engineering](https://sheetatlas.com/sectors/construction-engineering/): Professional CSI MasterFormat construction estimating workbooks, material takeoff calculators (concrete, drywall, roofing, framing, painting), NEC 1-Phase & 3-Phase electrical panel schedules, voltage drop sheets, and HVAC Manual J load calculators.
- [Accounting, Audit & Business Finance](https://sheetatlas.com/sectors/accounting-finance/): Senior CPA month-end close schedules, US GAAP & IFRS audit workpapers, prepaid expense amortization waterfalls, ASC 842 lease accounting models, Construction WIP schedules, 13-week rolling cash flow forecasts, and 3-way IOLTA trust reconciliations.

## Curated Collections
- [Free Construction Estimating & Material Takeoff Excel Templates](https://sheetatlas.com/collections/construction-estimating-and-takeoff-excel-templates/): CSI MasterFormat construction cost estimators, concrete & drywall takeoff spreadsheets, roofing & painting bid calculators, and contractor schedule of values (.xlsx).
- [Free NEC Electrical Panel Schedules & MEP Engineering Excel Calculators](https://sheetatlas.com/collections/nec-electrical-panel-schedules-and-mep-engineering-excel/): Licensed PE-grade 1-Phase and 3-Phase commercial electrical panel schedules, NEC Article 220 demand load calculators, voltage drop spreadsheets, HVAC Manual J calculators, and rebar bending schedules.
- [Free CPA Audit Workpapers & Month-End Close Schedule Excel Templates](https://sheetatlas.com/collections/cpa-audit-workpapers-and-month-end-close-excel-templates/): US GAAP and IFRS accounting workpapers for controllers and CPAs: prepaid expense amortization waterfalls, ASC 842 lease schedules, Construction WIP over/under billing, and fixed asset MACRS rollforwards.
- [Free 13-Week Cash Flow & 3-Way Trust Reconciliation Excel Models](https://sheetatlas.com/collections/cash-flow-forecasting-and-treasury-reconciliation-excel/): CFO treasury models, 13-week rolling liquidity forecasts, law firm IOLTA and property management 3-way trust account reconciliations, and operational recipe/unit costing calculators.

## Published Excel Workbooks (.XLSX)
- [Inventory Valuation Rollforward & Lower of Cost or Net Realizable Value (LCNRV) Calculator Excel Workpaper](https://sheetatlas.com/templates/inventory-valuation-rollforward-and-lcnrv-reserve-excel/): Free professional Inventory Valuation Rollforward & Lower of Cost or Net Realizable Value (LCNRV) Calculator Excel Workpaper (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [CSI MasterFormat 50-Division Construction Budget, Schedule of Values (SOV) & General Contractor Bid Excel Template](https://sheetatlas.com/templates/csi-masterformat-construction-budget-and-bid-summary-excel/): Free professional CSI MasterFormat 50-Division Construction Budget, Schedule of Values (SOV) & General Contractor Bid Excel Template (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Accounts Receivable (AR) Aging Report & CECL Bad Debt Allowance Calculator Excel Workpaper](https://sheetatlas.com/templates/accounts-receivable-aging-and-bad-debt-reserve-excel/): Free professional Accounts Receivable (AR) Aging Report & CECL Bad Debt Allowance Calculator Excel Workpaper (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Rebar Bending Schedule (BBS) & Steel Weight Takeoff Excel Template (ACI / ASTM Bar Sizes #3 to #11)](https://sheetatlas.com/templates/rebar-bending-schedule-bbs-weight-calculator-excel/): Free professional Rebar Bending Schedule (BBS) & Steel Weight Takeoff Excel Template (ACI / ASTM Bar Sizes #3 to #11) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Painting Contractor Takeoff & Bid Calculator Excel Spreadsheet (Interior/Exterior Sq Ft, Gallons & Labor Production)](https://sheetatlas.com/templates/painting-contractor-estimating-and-bid-calculator-excel/): Free professional Painting Contractor Takeoff & Bid Calculator Excel Spreadsheet (Interior/Exterior Sq Ft, Gallons & Labor Production) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Deferred Revenue Rollforward & ASC 606 SaaS Revenue Recognition Waterfall Excel Template](https://sheetatlas.com/templates/deferred-revenue-and-asc-606-waterfall-schedule-excel/): Free professional Deferred Revenue Rollforward & ASC 606 SaaS Revenue Recognition Waterfall Excel Template (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [NEC Voltage Drop & Copper/Aluminum Wire Sizing Calculator Excel Sheet (1-Phase & 3-Phase Feeder & Branch)](https://sheetatlas.com/templates/voltage-drop-and-wire-sizing-calculator-nec-excel/): Free professional NEC Voltage Drop & Copper/Aluminum Wire Sizing Calculator Excel Sheet (1-Phase & 3-Phase Feeder & Branch) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Month-End Close Checklist & Accrued Expenses Rollforward Workpaper Excel Template (Controller & CPA Edition)](https://sheetatlas.com/templates/accrued-expenses-and-month-end-close-checklist-excel/): Free professional Month-End Close Checklist & Accrued Expenses Rollforward Workpaper Excel Template (Controller & CPA Edition) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Restaurant Recipe Costing & Menu Engineering Excel Template (AP/EP Yield %, Plate Cost & Food Cost %)](https://sheetatlas.com/templates/restaurant-recipe-costing-and-menu-pricing-excel/): Free professional Restaurant Recipe Costing & Menu Engineering Excel Template (AP/EP Yield %, Plate Cost & Food Cost %) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Roofing Takeoff & Contractor Bid Estimator Excel Template (Roof Squares, Pitch Multiplier, Bundles & Labor)](https://sheetatlas.com/templates/commercial-and-residential-roofing-estimate-spreadsheet-excel/): Free professional Roofing Takeoff & Contractor Bid Estimator Excel Template (Roof Squares, Pitch Multiplier, Bundles & Labor) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Fixed Asset Rollforward & MACRS / GAAP Depreciation Schedule Excel Template (Straight-Line & Tax Basis)](https://sheetatlas.com/templates/fixed-asset-depreciation-and-macrs-schedule-excel/): Free professional Fixed Asset Rollforward & MACRS / GAAP Depreciation Schedule Excel Template (Straight-Line & Tax Basis) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Three-Way Trust Account Reconciliation Excel Template (Law Firm IOLTA & Property Management Audit Sheet)](https://sheetatlas.com/templates/three-way-trust-account-reconciliation-iolta-excel/): Free professional Three-Way Trust Account Reconciliation Excel Template (Law Firm IOLTA & Property Management Audit Sheet) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [HVAC Heat Load Calculation Excel Spreadsheet (Manual J Block Load, BTU/hr & Tonnage Sizing Calculator)](https://sheetatlas.com/templates/hvac-load-calculation-manual-j-spreadsheet-excel/): Free professional HVAC Heat Load Calculation Excel Spreadsheet (Manual J Block Load, BTU/hr & Tonnage Sizing Calculator) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [200-Amp Single-Phase Residential Panel Schedule Excel Template (120/240V NEC Article 220 Load Calculation)](https://sheetatlas.com/templates/residential-single-phase-panel-schedule-200-amp-excel/): Free professional 200-Amp Single-Phase Residential Panel Schedule Excel Template (120/240V NEC Article 220 Load Calculation) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [ASC 842 & IFRS 16 Operating Lease Accounting Excel Template (ROU Asset & Lease Liability Calculator)](https://sheetatlas.com/templates/asc-842-lease-accounting-amortization-schedule-excel/): Free professional ASC 842 & IFRS 16 Operating Lease Accounting Excel Template (ROU Asset & Lease Liability Calculator) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [13-Week Rolling Cash Flow Forecast Model Excel Template (Weekly Treasury Liquidity & Revolver Tracker)](https://sheetatlas.com/templates/13-week-cash-flow-forecast-model-excel-template/): Free professional 13-Week Rolling Cash Flow Forecast Model Excel Template (Weekly Treasury Liquidity & Revolver Tracker) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Concrete Takeoff & Cost Estimator Excel Template (Slabs, Footings, Columns, Rebar & Cubic Yards)](https://sheetatlas.com/templates/concrete-takeoff-and-cubic-yard-estimator-excel/): Free professional Concrete Takeoff & Cost Estimator Excel Template (Slabs, Footings, Columns, Rebar & Cubic Yards) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Construction WIP Schedule Excel Template (Over/Under Billing & ASC 606 Percentage of Completion)](https://sheetatlas.com/templates/construction-wip-schedule-over-under-billing-excel/): Free professional Construction WIP Schedule Excel Template (Over/Under Billing & ASC 606 Percentage of Completion) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Drywall Takeoff & Material Cost Estimator Excel Spreadsheet (4x8 & 4x12 Sheet Count, Mud, Tape & Labor)](https://sheetatlas.com/templates/drywall-takeoff-and-estimate-spreadsheet-excel/): Free professional Drywall Takeoff & Material Cost Estimator Excel Spreadsheet (4x8 & 4x12 Sheet Count, Mud, Tape & Labor) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [Prepaid Expense Amortization Schedule & Month-End Rollforward Workpaper Excel Template (US GAAP)](https://sheetatlas.com/templates/prepaid-expense-amortization-schedule-excel-template/): Free professional Prepaid Expense Amortization Schedule & Month-End Rollforward Workpaper Excel Template (US GAAP) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.
- [3-Phase Commercial Electrical Panel Schedule Excel Template (208Y/120V & 480Y/277V NEC Load Calculator)](https://sheetatlas.com/templates/3-phase-electrical-panel-schedule-excel-template/): Free professional 3-Phase Commercial Electrical Panel Schedule Excel Template (208Y/120V & 480Y/277V NEC Load Calculator) (.XLSX) with automated formulas, multi-sheet schedules, and interactive calculator preview.