Decorating calculators

Quick planning tools for holiday lights and Halloween décor — from eave strand counts and circuit headroom to specialty helpers like luminaria candle packs, gift-box stack stability, blow-mold driveway lines, nutcracker porch fit, pumpkin pillar height, porch mitten clips, tombstone LED pack nights, present-bow diagonals, eave ornament hooks, cauldron dry-ice pounds, mailbox swag bow fit, skull path markers, projector window coverage, silhouette stakes, porch lantern chain, reindeer antler wraps, ladder clip rung moves, graveyard fog-fan CFM, wreath S-hooks, candy-chute slope, spider-web corners, cobweb spray cans, spotlight stake depth, village street length, hanging-ghost clearance, light storage reels, tomato-cage trees, light balls, coffin plywood, graveyard fence panels, prop motion-sensor reach, roof star size, garland adhesive hooks, wreath storage boxes, and snowflake tree hangs. All math runs in your browser — nothing is uploaded. Each calculator shows the formula, a when-to-use note, a worked example, and limits/assumptions.

These are decorating planning aids for Prince William County homeowners — measure once, buy closer to the right quantity, then confirm against product labels and outdoor GFCI ratings. Browse by job (power, clips, Halloween props, porch fit) and keep a spare pack of clips or candles on the list when the tool suggests it. Not an electrical-code stamp or install quote. Questions? About · Contact.

Not sure where to start? Measure first, then pick by the question you are asking. “How many?” questions (strands, clips, hooks, panels, snowflakes) use your measured feet and a spacing. “Will it fit or clear?” questions (wreath boxes, hanging ghosts, porch urn inserts) compare two measurements with a margin. “Is it safe to plug in?” questions (amp draw, circuit headroom, cord gauge) compare nameplate watts with a rating — when those disagree with a product label, the label wins. Most pages also show a second example so you can see which measurement moves the answer the most.

• Bush net count Bush height × width → how many light nets given net size.
• Icicle light count Eave length ÷ set length → icicle strands (plus clip spacing estimate).
• C9 / C7 bulb count Linear feet ÷ socket spacing → C9 or C7 bulb/socket count.
• Roof clip count Eave + ridge feet ÷ clip spacing → gutter/shingle clips.
• Tree strand count Tree height × wrap density → mini-light strands.
• LED watt savings Incandescent vs LED watts × hours × your $/kWh → savings.
• Outdoor cord voltage drop 120V light load + cord AWG + feet → approximate voltage drop.
• Garland length Stairs, mantel, and door openings × drape factor → garland feet.
• Inflatable amp draw Nameplate watts → amps and remaining headroom on a 15A circuit.
• Window candle count Windows × candles per window → candle order quantity.
• Display kWh cost Total watts × hours × nights × your rate → season kWh and cost.
• Extension cord gauge picker Watts + cord feet → suggested outdoor AWG for light runs.
• GFI circuit headroom Existing watts vs 15A/20A GFCI limit → leftover amps.
• Roof peak strand count Peak/ridge length × pitch factor → strands needed.
• Wreath bow ribbon length Wreath diameter + loops + tails → ribbon feet.
• Pumpkin carving time Pumpkins × minutes ÷ carvers → party wall-clock time.
• Halloween costume budget Costumes × budget + accessories + contingency → total.
• Pathway light stake count Walkway length ÷ spacing → stake quantity (+ spares).
• Power strip outlet derate Strip amps × volts × continuous derate % vs light watts.
• C9 wire length Sockets × spacing → socket-wire feet (+ lead/spare).
• Mesh net overlap waste Coverage area vs net size with overlap % → nets + waste.
• Stake light run length Path length ÷ spacing → stakes + cord feet.
• Timer on-hours per season Hours/night × nights → season hours (optional kWh).
• Gingerbread house candy count Wall/roof panel area × density → candy pieces.
• Halloween bag candy pieces Bags × pieces/bag ÷ kids (or bags to buy).
• Projection mapping distance Throw ratio × image width → projector distance.
• Outdoor receptacle count Yard run length ÷ spacing → outlet count.
• LED controller channel load Channels × watts/channel vs PSU rating (+ headroom %).
• Inflatable tie-down stake count Perimeter ÷ spacing → stakes + guy lines.
• Curtain light drop count Width × drops/ft → vertical strands (+ height feet).
• Mailbox swag garland Post wraps + top swag drape → garland feet.
• Porch column wrap length Circumference × turns from pitch → strand feet.
• Battery pack runtime for LEDs mAh × V × usable% ÷ LED watts → hours.
• Lighted deer spacing Frontage ÷ spacing × rows → yard deer count.
• Yard maze stake count Wall edge length ÷ spacing + corners → stakes.
• Extension reel capacity check Holiday watts vs reel amps with continuous derate.
• Rope light channel length Channel path × fill factor (+ spare) → rope feet; optional cut-interval round-up.
• Balloon column base weight Column height → sandbag lbs (indoor + outdoor ×2).
• Scarecrow pole height Display height + bury depth (fixed or 1/3) → pole length.
• Hay bale stack count Wall L×H ÷ bale face → bales for a display wall.
• Christmas village shelf length Buildings × footprint + gaps → shelf feet.
• Outdoor speaker cable run One-way feet + impedance/power → suggested AWG.
• Wreath hanger door clearance Door top gap vs hanger hook thickness → pass/fail.
• Icicle drip tier count Eave × drip density ÷ drips-per-set → sets.
• Net light bush volume Bush H×W×D ÷ net coverage volume → nets.
• Porch railing bow count Rail sections × bows/section (or length ÷ spacing).
• Timer astronomical offset Season nights × evening window (sunset ± offset).
• Fence picket light spacing Pickets × wrap turns × height → light feet / clips.
• Snow blanket roll coverage Area ÷ roll coverage (+ waste %) → rolls.
• Halloween fog low-lying mix Chest qt × ice density → ice lb, melt water, runtime hint.
• Christmas tree stand water days Reservoir qt ÷ daily qt → days until empty.
• Outdoor ribbon tree wrap length Wrap height ÷ pitch × circumference → ribbon feet.
• Halloween spider web coverage Area ÷ package coverage (or corners × webs) → packs.
• Window silhouette panel count Windows × panels/window (or sheet vs pane grid).
• Garland stair banister length Banister path × drape factor + end drops → garland ft.
• Inflatable anchor sandbag weight Anchor points × lbs/point (height/wind tier) → ballast.
• LED icicle amp per set Sets × W/set ÷ 120 → amps vs end-to-end limit.
• Garland mantel swag bow count Swag dips × bows (or mantel ÷ spacing).
• Net light overlap bush face Face area ÷ panel (with overlap) → nets.
• Inflatable cord amp budget Blowers × W ÷ 120 vs 80% circuit headroom.
• Outdoor bow ribbon yardage Bows × yd/bow × waste% → yards & spools.
• Tree topper spike clearance Ceiling − tree − stand − topper → clearance pass/fail.
• Mantel candle cluster count Usable mantel ÷ spacing → clusters × candles.
• Halloween bat window cling count Window ft² × density → bat clings.
• Porch urn insert height fit Max height − urn − insert → clearance pass/fail.
• Halloween hanging spider drop Mount − drop vs walker height → walk clearance.
• Halloween tombstone foam paint ounces Stones × face ft² × coats × oz/ft² × accent% → paint oz.
• Outdoor lighted present stack count Run ÷ (stack width + gap) → pre-lit gift stacks.
• Christmas village platform area Buildings × padded base ÷ 144 → platform ft².
• LED curtain width panel count Opening width ÷ panel width (with overlap) → panels.
• Halloween fog hose run length Horizontal + rise×factor + spare → hose feet.
• Halloween witch hat tree count Hang height ÷ spacing × trees → witch hats.
• Outdoor candle lantern fuel nights Fuel oz ÷ (oz/hr × hours × lanterns) → nights.
• Pathway luminaria candle hours Bags × hours × nights ÷ burn → candle packs.
• Lighted gift box stack stability Base width × ratio ÷ box height → max tiers.
• Outdoor blow mold driveway count Driveway run ÷ spacing → blow-mold figures.
• Outdoor nutcracker porch fit Porch depth/width/height vs figure → fit.
• Halloween pumpkin pillar max height Base diameter × ratio vs stack height.
• Porch mitten clip count Rail ÷ mitten spacing → clips.
• Halloween tombstone LED nights Stones × LED W × hours → battery pack nights.
• Christmas present bow diagonal Box face diagonal → bow span / ribbon loops.
• Outdoor ornament hook eave count Eave run ÷ hook spacing → ornament hooks.
• Halloween cauldron dry ice (lb) Fog hours × lb/hour → dry ice pounds.
• Christmas mailbox swag bow fit Mailbox width vs bow span → fit check.
• Halloween yard skull path count Path × sides ÷ spacing → skull markers.
• Outdoor projector window count Windows ÷ coverage width → projectors.
• Spooky silhouette stake count Frontage × rows ÷ spacing → silhouette stakes.
• Porch lantern chain length Ceiling − body − target bottom → chain.
• Reindeer antler wrap feet Antler path × turns → ribbon/garland feet.
• Christmas ladder light clip rung count Rungs × clips/rung → ladder moves for an eave.
• Halloween graveyard fog fan CFM Path volume × gentle factor → assist fan CFM.
• Outdoor wreath S-hook door count Mounts × wreaths × hooks → S-hook pack.
• Halloween candy chute slope Rise/run → angle; pass vs candy target°.
• Halloween spider web corner count Corners × kits; radials × rings → weave points.
• Halloween cobweb spray cans Area × coats ÷ label coverage → cans.
• Outdoor spotlight stake depth Stem × soil × wind → embed inches.
• Christmas village street length Buildings × width + gaps → street inches.
• Halloween hanging ghost clearance Ghost length + clearance → mount height.
• Christmas light storage reel capacity Flange, hub, width → feet per reel and reels needed.
• Tomato cage tree light count Cage height × ring diameter × wrap spacing → lights and strands.
• Christmas light ball strand length Ball diameter × row spacing → feet, lights, strands per ball.
• Halloween coffin prop plywood sheets Coffin outline + depth → side lengths, area, 4×8 sheets.
• Halloween graveyard fence panel count Run − openings ÷ panel width → panels, posts, pickets.
• Halloween prop motion sensor walkway coverage Setback, range, angle → walkway coverage and trigger point.
• Roof star size for street view Viewing distance + height → apparent size and target star diameter.
• Garland adhesive hook count Garland length + weight ÷ hook rating → hook count and load each.
• Wreath storage box fit Wreath diameter + depth + clearance → box fit and size to buy.
• Outdoor snowflake tree hang count Canopy width + spacing + tiers → snowflake count, drops, clearance.

Estimates only — always follow manufacturer ratings and local electrical safety practices.