Invoice Total Calculator
Add line items and calculate subtotal, discount, tax, and total
| Item | Quantity | Unit price | Line total |
|---|
Invoice Total Calculator — what it does
Add line items with quantity and unit price and get the subtotal, discount amount, tax amount and grand total as you go. It is the arithmetic half of invoicing without the document: useful when you are checking a supplier's figures or quoting a total over the phone.
When this tool helps
- Checking a received invoice's arithmetic before approving it for payment.
- Quoting a total on a call, with quantities and a discount applied live.
- Working out what to charge before writing the actual invoice.
How to use it
- Add an item with its quantity and unit price.
- Repeat for each line, watching the line totals.
- Set the discount and tax rates.
- Calculate to see subtotal, discount, tax and grand total.
Accuracy, limits, and good practice
- Discount is applied before tax, matching standard invoicing practice — reversing the order changes the total slightly and is usually wrong.
- Line totals are rounded per line; a grand total may differ by a cent from a single calculation on the unrounded figures.
- For a document to send, the invoice generator produces the same arithmetic with a printable layout around it.
Frequently asked questions
Can I use different tax rates per line?
One rate applies to the whole invoice here. For mixed rates, calculate each group separately and add the results.
Is the discount per item or on the total?
On the subtotal. To discount a single line, adjust that line's unit price instead.
Does it round the way accounting software does?
Standard rounding is applied per line and to totals; a difference of a cent against another system's rules is possible and normal.
Related tools on this site
- Work Hours Calculator — Calculate paid hours, break time, and estimated pay
- CAGR Calculator — Calculate compound annual growth rate over a period
- Inventory EOQ & Reorder Calculator — Calculate EOQ, reorder point, annual orders, and order cycle
Everything above runs inside this page. Invoice Total Calculator needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
發票總額計算器能做什麼
逐項加入數量與單價，即時得到小計、折扣金額、稅額與總計。它是請款的算術部分、沒有文件外殼：核對供應商的數字，或在電話上口頭報總價時特別好用。
什麼時候用得上
- 在核准付款前，先驗算收到的請款單。
- 在通話中報總價，數量與折扣即時套用。
- 在正式開單之前先算清楚該收多少。
使用步驟
- 加入一個品項，填上數量與單價。
- 逐行重複，同時檢視各行小計。
- 設定折扣率與稅率。
- 計算後查看小計、折扣、稅額與總計。
精確度、限制與實務建議
- 折扣先於稅額套用，符合標準開票實務——順序反過來總額會略有差異，通常是錯的。
- 各行小計會逐行四捨五入，總計可能與「以未捨入數字一次計算」的結果差一分錢。
- 需要可寄出的文件時，發票生成器提供相同算術，外加可列印的排版。
常見問題
每一行可以用不同稅率嗎？
此處整張單套用單一稅率。稅率混雜時，請分組各自計算後再加總。
折扣是逐項還是總額？
作用在小計上。若只想折某一行，請直接調整該行單價。
四捨五入方式與會計軟體一樣嗎？
逐行與總額都採標準捨入；與其他系統規則相差一分錢是可能且正常的。
本站相關工具
- 工時計算器 — 計算實際工時、休息時間與預估薪資
- CAGR 年複合成長率 — 計算一段期間內的年複合成長率
- 庫存 EOQ 與補貨點計算器 — 計算經濟訂購量、補貨點、年度訂購次數與週期
以上步驟全部在這個頁面內完成，發票總額計算器 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。