Free retail planning calculators
A retail planning calculator runs one piece of retail math — open-to-buy, sell-through, GMROI, markup, cover — on numbers a planner already has, and returns a figure that supports a buy, a markdown or a reorder decision. Every calculator here is free, needs no sign-up, and shows the formula it runs so the answer can be checked by hand.
They are vendor-neutral and they are deliberately single-purpose. Each one answers a question in isolation; a real season answers all of them at once, against one plan, which is the difference between doing the math and running the process.
Start from the question, not the metric
Most planning questions have one formula behind them and one calculator that runs it. Working from the question rather than the metric name is what stops a team reaching for GMROI when the question was really about cover, or for a markdown percentage when the question was how many extra units the markdown has to sell.
| The question | The formula | The calculator |
|---|---|---|
| What should this season or year sell, and how much in each month? | Planned sales = last year × (1 + growth %); each period = planned sales × its share of a profile summing to 100% | Sales plan calculator → |
| How much can I still commit to buy this period? | OTB = planned EOP stock + planned sales + planned markdowns − BOP stock − on order | Open-to-buy calculator → |
| Where does my stock end up if intake and sales land as planned? | Closing stock = opening stock + intake − sales − markdowns; cover = closing ÷ average weekly sales | WSSI calculator → |
| Is this style selling fast enough to chase, or slow enough to mark down? | Sell-through % = units sold ÷ units available (opening stock + receipts) × 100 | Sell-through calculator → |
| What margin am I earning per dollar of inventory I hold? | GMROI = gross margin $ ÷ average inventory at cost | GMROI calculator → |
| What retail price hits the markup my plan needs? | IMU % = (retail − cost) ÷ retail; retail = cost ÷ (1 − target IMU %) | IMU calculator → |
| What markup did the goods actually keep after markdowns, and what IMU does a margin target need? | MMU % = (net sales − cost of goods sold) ÷ net sales; required IMU % = (MMU % + reductions %) ÷ (100% + reductions %) | Maintained markup calculator → |
| What is my inventory worth at cost, and what did the goods I sold cost? | Cost complement = goods available at cost ÷ goods available at retail; ending inventory at cost = ending inventory at retail × cost complement | Retail inventory method calculator → |
| How many times is this inventory turning? | Inventory turn = cost of goods sold ÷ average inventory at cost | Inventory turnover calculator → |
| How long will the stock I am holding last? | Weeks of supply = current stock ÷ average weekly sales | Weeks of supply calculator → |
| How much stock should a period open with? | Stock-to-sales ratio = BOP stock ÷ sales for the period | Stock-to-sales ratio calculator → |
| What does this markdown do to price and to margin? | Markdown % = markdown $ ÷ original retail; new retail = original × (1 − markdown %) | Markdown calculator → |
| How many extra units does a markdown have to sell to stand still? | Required unit lift = original margin $ per unit ÷ reduced margin $ per unit − 1 | Break-even markdown calculator → |
| How do I split a buy across a size run? | Units by size = total units × that size’s share of the size curve | Size curve calculator → |
| What does this product actually cost me once it lands? | Landed cost = FOB + freight + duty + insurance + inbound handling, per unit | Landed cost calculator → |
| How much of my wholesale book am I actually shipping? | Fill rate = units shipped ÷ units booked | Sell-in and bookings calculator → |
| Is my supply chain hitting its dates, and what does a slip cost? | On-time delivery % = deliveries on or before the date ÷ total deliveries | Lead-time and on-time-delivery calculator → |
The full formula reference, with definitions and worked examples for each, is in retail math formulas.
The retail inventory method: a calculator and a guide
One question the other calculators do not answer is what the inventory is worth. The retail inventory method values a pool of stock at its retail ticket and converts it to cost with a single ratio — the cost complement, cost of goods available for sale divided by retail of goods available for sale. The retail inventory method calculator runs a period’s two-column stock ledger and returns the complement, ending inventory at retail and at cost, and cost of goods sold, using the conventional method with the average-cost variant shown beside it.
The calculator does the arithmetic; the method’s judgement calls — which pool one complement can honestly describe, how the shrink provision is tested by a physical count, and why a mixed-margin department is valued wrongly — are worked through in the guide. For a single style, the IMU calculator returns initial markup on retail, and one minus that figure is that style’s cost complement.
- Definition — Cost complement
- The share of a retail dollar that is cost, for a pool of inventory. One minus the cost complement is the pool’s cumulative markup on retail, and the complement itself is the multiplier that turns a retail stock position into inventory at cost — the denominator of GMROI.
- Cost complement = cost of goods available for sale ÷ retail of goods available for sale
- Used by: Retail finance for the close; planners converting a plan held at retail into inventory at cost
- Related: Initial markup, maintained markup, gross margin, GMROI, retail inventory method
Size the opportunity and pressure-test the buy before you commit.
ROI / Margin Opportunity Calculator →
Size the margin recovered from fewer markdowns and the working capital freed by faster turns — your targets.
- Best for
- Owners and finance leads
- Use when
- You want to size the margin and working capital a connected plan could free up.
Sales Plan Calculator →
A retail sales target from last year and a growth rate or target total — the comp and non-comp split, and the plan phased by month or 4-5-4 period.
- Best for
- Planners and merchandise finance
- Use when
- You are setting the sales target for a season or year and need it phased by period before open-to-buy.
Open-to-Buy (OTB) Calculator →
Retail dollars you can still receive this period — and whether you are overbought.
- Best for
- Buyers and planners
- Use when
- You need to understand how much inventory you can still buy for a period.
WSSI Calculator →
Weekly Sales, Stock & Intake — project closing stock and weeks of cover.
- Best for
- Merchandisers and planners
- Use when
- You need to project closing stock and weeks of cover for a period.
Lead-Time / On-Time-Delivery Calculator →
Project an order’s arrival against the in-store date and see the slip risk.
- Best for
- Sourcing and production teams
- Use when
- You need to check whether an order will land before its in-store date.
Check how the inventory you already own is performing against plan.
Sell-Through Rate Calculator →
The share of received units that have sold — reorder or markdown signal.
- Best for
- Buyers and planners
- Use when
- You want a reorder-or-markdown read on how a style is selling through.
GMROI Calculator →
Gross-margin dollars earned per dollar of inventory at cost.
- Best for
- Planners and finance leads
- Use when
- You want to measure the margin return on each dollar of inventory held.
Initial Markup (IMU) Calculator →
The first markup on a style — and the margin that survives your markdowns.
- Best for
- Buyers, planners, and finance leads
- Use when
- You are setting a price and want to leave room for markdowns and still hit margin.
Maintained Markup (MMU) Calculator →
The markup that survived markdowns, discounts and shrink — MMU in dollars and percent from net sales and cost, the implied IMU, and the IMU a target MMU and planned reductions require.
- Best for
- Planners, buyers and finance leads
- Use when
- You want to measure the markup a class actually kept, or set the first ticket so a target margin survives the reductions you expect.
Retail Inventory Method Calculator →
The cost complement, ending inventory at retail and at cost, and COGS from a period’s stock ledger — conventional retail method.
- Best for
- Planners and retail finance leads
- Use when
- You hold the stock ledger at retail and need inventory at cost and cost of goods sold for the period.
Inventory Turnover Calculator →
How many times inventory sells through and is replaced over a period.
- Best for
- Planners and finance leads
- Use when
- You want to see how quickly inventory cycles relative to plan.
Weeks of Supply Calculator →
How many weeks current stock will last at the recent sales rate.
- Best for
- Merchandisers and planners
- Use when
- You need to know how long current stock will cover demand.
Stock-to-Sales Ratio Calculator →
BOM stock per unit of period sales — the multiplier behind BOM stock targets.
- Best for
- Merchandisers and planners
- Use when
- You are setting BOM stock targets or reading cover against demand.
The apparel-specific math behind a size-aware, margin-aware buy.
Size Curve Calculator →
Turn sales history into the size distribution to buy by.
- Best for
- Buyers and allocators
- Use when
- You need to split a buy across sizes based on demand.
Markdown Calculator →
The markdown percentage, sale price, and margin impact of a price cut.
- Best for
- Buyers and planners
- Use when
- You need to work out the price and margin impact of a markdown.
Break-Even Markdown Calculator →
The markdown depth where margin per unit hits zero — and the unit lift a markdown needs to hold margin dollars flat.
- Best for
- Buyers and planners
- Use when
- You are deciding how deep a markdown can go, or what volume it has to earn back.
Sell-In & Bookings Calculator →
Wholesale booking attainment (booked vs. plan) and fill rate (shipped vs. booked).
- Best for
- Wholesale and sales teams
- Use when
- You need to track booking attainment and fill rate against plan.
Landed Cost & Margin Calculator →
True landed cost from FOB + freight + duty, and the gross margin at a target retail price.
- Best for
- Sourcing and finance leads
- Use when
- You need true landed cost and the margin at a target retail price.
These are merchandise planning calculators. They work on inventory, margin, intake and delivery — not on property, fit-out, payroll or store operating costs, and none of them estimates the cost of opening or running a store. The nearest thing on this page is the landed cost calculator, which builds a per-unit product cost from FOB, freight, duty, insurance and inbound handling; that is a cost-of-goods figure rather than a cost-of-occupancy one.
They also each answer one question at a time. The directional ranges a planner reads these figures against are in planning benchmarks, the step-by-step method behind each one is in the guides, the terms are defined in the glossary, and the formula-driven Excel versions are in the templates.
Frequently asked questions
- What is a retail calculator?
- A retail calculator runs one piece of retail math on numbers you already have — sales, receipts, stock, cost and ticket price — and returns a figure a planner can act on. The calculators on this page cover the retail math that sits behind a merchandise plan: the sales plan, open-to-buy, weekly sales stock and intake, sell-through, GMROI, initial markup, the retail inventory method, inventory turn, weeks of supply, stock-to-sales, markdown depth, size curves, landed cost, fill rate and on-time delivery. Each shows the formula it runs, so the answer is checkable rather than a black box.
- Which retail calculator should I use for which question?
- Work from the question rather than the metric. What should the season sell, and in which months — the sales plan. How much can I still buy — open-to-buy. Where does stock land if intake and sales go to plan — WSSI. Is this selling fast enough to chase — sell-through. What am I earning per dollar of inventory — GMROI. What price hits my markup — IMU. What is the stock worth at cost, and what did the goods sold cost — retail inventory method. How long will this stock last — weeks of supply. What does a markdown do to margin — markdown, then break-even markdown for the unit lift it needs. The table on this page maps every question to its formula and its calculator.
- Is there a retail inventory method calculator?
- Yes. The retail inventory method calculator takes a period’s stock ledger — beginning inventory and purchases at cost and at retail, freight-in, additional markups and markup cancellations, net sales, markdowns, employee discounts and estimated shrink — and returns goods available for sale, the cost complement (cost of goods available ÷ retail of goods available), ending inventory at retail and at cost, and cost of goods sold. It uses the conventional, lower-of-cost-or-market method, which does not deduct markdowns from the complement’s retail base, and shows the average-cost variant beside it. The guide to the retail inventory method covers choosing the pool, the physical-count restatement and where the method breaks.
- Is there a sales target or sales goal calculator?
- Yes. The sales plan calculator sets a retail sales target from last year’s sales for the period and a planned growth rate — planned sales = last year × (1 + growth %) — or back-solves the growth from a target total you have been given. It splits the change into comp growth from the doors and channels that traded last year and non-comp growth from new doors and channels, and phases the total across twelve months or 4-5-4 periods with a seasonality profile it checks sums to 100%. The guide to setting a sales plan covers the top-down and bottom-up builds and how to reconcile them.
- Do these calculators estimate the cost of opening or running a store?
- No. These are merchandise planning calculators: they work on inventory, margin and intake, not on property, fit-out, payroll or store operating costs. The closest thing here is the landed cost calculator, which builds a per-unit product cost from FOB, freight, duty, insurance and inbound handling — a cost-of-goods figure rather than a cost-of-occupancy one.
- Are these calculators free, and is anything gated?
- Every calculator on this page is free and runs in the browser with no sign-up. The downloadable Excel templates are a separate section, and some of those ask for a work email. The calculators themselves ask for nothing.
These do the math one figure at a time. RetailNorthstar runs it across every style, channel, and season — connected to one plan.
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