From a net amount (what you actually want to receive) and a deduction rate, reverse out the gross amount before deductions and the deducted amount, for 'how much to charge to net X' calculations.
Input Data
Results
At a glance:Given a desired net amount and a deduction rate on the gross, the gross is the net divided by (1 minus the rate), and the deducted amount is the difference.
Formula
gross = net / (1 − deductionRatePct%)
deducted = gross − net
$$Gross = \\dfrac{Net}{1 - DeductionRate}$$$$Deducted = Gross - Net$$How to Use
- Enter the target net amount.
- Enter the deduction rate.
- Review the gross amount and the deducted amount.
FAQ
Why do we reverse with division instead of adding the rate back to the net?
This is the most common mistake. Intuitively one might add 15% back: net × (1 + 15%). But the deduction is calculated on the gross, not the net. The correct relation is net = gross × (1 − rate). To reverse it, solve for gross: gross = net ÷ (1 − rate). With net 25,500 and 15%: gross = 25,500 ÷ 0.85 = 30,000 (check: 30,000 × 15% = 4,500; 30,000 − 4,500 = 25,500 ✓). The wrong way, 25,500 × 1.15 = 29,325, would leave you short. The higher the rate, the bigger the gap, so always use division.
When is this reverse calculation most useful?
The reverse 'net-to-gross' thinking is practical in many situations. First, salary negotiation: if you have a clear take-home target, you can reverse out the pre-tax salary needed to reach it. Second, quoting and pricing: when you know a platform fee or commission will be taken and you want to net a certain amount, you can reverse out the total price to charge. Third, budgeting and target planning: set a net target and reverse out the gross needed. Fourth, checking a statement: use it to verify whether the gross looks right. The key is to reasonably estimate the combined deduction rate and confirm it is based on the gross.
What limits should I watch out for with this calculator?
This is a simplified single-rate model. First, the deduction rate must be under 100%; at 100% the denominator is zero and above it the net cannot be positive, so the calculator returns 0 — check your input. Second, real deductions are often progressive or capped; for example Hong Kong salaries tax is progressive with allowances, and MPF has income caps, so a single fixed rate only approximates the true gross. Third, if deductions are based on different bases or in sequence, a single rate is inaccurate. Rounding is to two decimals. Use this for rough reverse estimates, not a substitute for precise tax or payroll computation.
How do I combine multiple deductions (tax, MPF, others) into one rate?
If all deductions are fixed percentages based on the same gross, simply add the rates: tax 10% + MPF 5% + others 3% = 18% combined, then use gross = net ÷ (1 − 18%). But reality is messier: if deductions are sequential (one deducted after another), involve fixed amounts, or are progressive/capped (like salaries tax or MPF caps), adding rates no longer gives the true figure. For those cases, treat the single-rate result as an approximation and add a buffer, or use a dedicated tax/payroll tool for accurate figures.
How is 'net to gross' different from 'gross to net', and which do I use?
They are the opposite direction of the same idea. 'Gross to net' (forward) takes the known pre-deduction amount and works out what you keep: net = gross × (1 − rate) — used when you have an offer or total and want to know the take-home. 'Net to gross' (this calculator) takes the net you want and works back to the gross you must set: gross = net ÷ (1 − rate) — used when you have a target take-home and want to know the salary to ask for or the price to quote. Remember: forward uses multiplication by (1 − rate), reverse uses division; never use multiplication by (1 + rate) in reverse.
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.