Formula sheet
The formulas behind our calculators, each with a worked example. The examples are worked out by the same code the tools use.
Typing speed (WPM)
Gross WPM = (characters typed ÷ 5) ÷ minutes · Net WPM = (characters ÷ 5 − mistakes) ÷ minutes
One “word” is 5 key depressions, spaces included. Example: 1,750 characters in 10 minutes is 35 gross WPM; with 12 mistakes it is 33.8 net WPM.
Key depressions per hour (KDPH)
KDPH = WPM × 5 × 60 = WPM × 300
35 WPM = 10,500 KDPH and 30 WPM = 9,000 KDPH, the figures the SSC CHSL 2026 notice gives. An 8,000 KDPH DEO test is 26.67 WPM.
SSC error percentage
Error % = (full mistakes + ½ × half mistakes) ÷ words in the passage you covered × 100
Full mistakes: a word missed, added or wrong. Half mistakes: spacing, capitals, punctuation, swapped words. Example: 6 full + 4 half over 350 words = 2.29%.
Marks with negative marking
Marks = right × marks per question − wrong × negative mark (unattempted = 0)
SSC Tier-I (+2, −0.5): 70 right and 20 wrong = 140 − 10 = 130.
Age limit as birth dates
Born not earlier than (crucial date − upper limit) + 1 day, and not later than crucial date − lower limit. Relaxation adds years to the upper limit.
18–27 years on 01-08-2026: born from 02-08-1999 to 01-08-2008. With OBC relaxation (+3, so 30): from 02-08-1996.
CGPA to percentage
Percentage = CGPA × 9.5 (CBSE’s formula; your university may use its own)
CGPA 8.2 × 9.5 = 77.9%.
Central government salary
Gross = basic pay + DA (basic × DA%) + HRA (basic × city rate) + TA (+ DA on TA)
Level 4 in a Y city: ₹25,500 + DA 63% ₹16,065 + HRA 20% ₹5,100 + TA ₹2,934 = ₹49,599 a month before deductions. DA changes twice a year.
Photo size: cm to pixels
Pixels = cm ÷ 2.54 × DPI · KB = bytes ÷ 1024 (some portals use 1000)
3.5 cm × 4.5 cm at 200 DPI = 276 × 354 px.
Sources: SSC “Revised Guidelines for Evaluation of Typing Test/DEST Scripts” (mistakes), SSC CHSL 2026 notice para 13.9.13.7 (WPM and KDPH), CCS (Revised Pay) Rules, 2016, G.S.R. 721(E), 25.07.2016, Schedule Part A (Gazette of India copy), Department of Expenditure OM No. 1/2(i)/2026-E.II(B), 29.10.2026 (DA 63% from 01.07.2026).