List what the project needs: labour in days or hours, purchases and expenses. Add an overhead rate, a contingency and a profit margin if you use them. You get the total project cost, the price that gives your margin and, when labour is in days, the full cost and the price per person-day. Amounts are rounded to the nearest penny, and your estimate stays on this device unless you save it.
Enter the lines
One line per item: a role for a number of days or hours, a purchase, a trip. The quantity times the unit cost gives the line amount. A line without a quantity or a unit cost is not counted, and the calculator tells you so.
Add overheads and contingency
Overheads are the costs no single project carries on its own, such as rent, software and accounting, applied as a percentage of direct costs. Contingency is money set aside for the risks you have identified, applied to direct costs plus overheads. Leave either empty if your unit costs already include it.
Set the margin
Choose whether your margin is on cost (a markup) or on the selling price. A 20% markup gives a price of cost × 1.2; a 20% margin on price gives cost ÷ 0.8. The result shows both rates side by side. Leave the margin empty to see the cost only.
Line amount = quantity × unit cost.
Direct costs = labour + purchases and expenses.
Overheads = direct costs × overhead rate.
Contingency = (direct costs + overheads) × contingency rate.
Total cost = direct costs + overheads + contingency.
Price = total cost × (1 + rate) for a markup on cost, or total cost ÷ (1 − rate) for a margin on price.
Each amount is rounded once, to the nearest penny; a half penny rounds up.
Example: a 15 person-day website build
15 days at £480.00 is £7,200.00 of labour; with £900.00 of hosting and licences, direct costs come to £8,100.00. Overheads at 12% add £972.00, and a 10% contingency on £8,100.00 + £972.00 adds £907.20, so the project costs £9,979.20, or £665.28 per person-day. A 25% markup gives a price of £12,474.00 before VAT and a profit of £2,494.80, which is a 20% margin on price.
